Connectors and APIs - MariaDB - Databases - Software - Computers


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Connectors and APIs

Table of Contents

MySQL Connector/ODBC
Connector/ODBC Versions
Connector/ODBC Introduction
Connector/ODBC Installation
Connector/ODBC Configuration
Connector/ODBC Examples
Connector/ODBC Reference
Connector/ODBC Notes and Tips
Connector/ODBC Support
MySQL Connector/Net
Connector/Net Versions
Connector/Net Installation
Connector/Net Visual Studio Integration
Connector/Net Tutorials
Connector/Net Programming
Connector/Net Connection String Options Reference
Connector/Net API Reference
Connector/Net Support
Connector/Net FAQ
MySQL Connector/J
Overview of MariaDB Connector/J
Connector/J Versions
Connector/J Installation
Connector/J Examples
Connector/J (JDBC) Reference
JDBC Concepts
J2EE Concepts
Using Connector/J with Tomcat
Using Connector/J with JBoss
Using Connector/J with Spring
Using Connector/J with GlassFish
Troubleshooting Connector/J
Connector/J Support
MySQL Connector/MXJ
Overview of Connector/MXJ
Connector/MXJ Versions
Connector/MXJ Installation
Connector/MXJ Configuration
Connector/MXJ Reference
Connector/MXJ Notes and Tips
Connector/MXJ Samples
Connector/MXJ Support
MySQL Connector/C++
Installing the MariaDB Connector/C++ Binary
Installing MariaDB Connector/C++ from Source
MySQL Connector/C++ Building Windows Applications with Microsoft Visual Studio
MySQL Connector/C++ Building Linux Applications with NetBeans
MySQL Connector/C++ Getting Started: Usage Examples
MySQL Connector/C++ Tutorials
MySQL Connector/C++ Debug Tracing
MySQL Connector/C++ Usage Notes
MySQL Connector/C++ Known Bugs and Issues
MySQL Connector/C++ Feature requests
MySQL Connector/C++ Support
MySQL Connector/C++ FAQ
MySQL Connector/C
Building MariaDB Connector/C from the Source Code
Testing MariaDB Connector/C
MySQL Connector/C FAQ
MySQL Connector/OpenOffice.org
Installation
Getting Started: Connecting to MySQL
Getting Started: Usage Examples
References
Known Bugs
Contact
libmysqld, the Embedded MariaDB Server Library
Compiling Programs with libmysqld
Restrictions When Using the Embedded MariaDB Server
Options with the Embedded Server
Embedded Server Examples
Licensing the Embedded Server
MySQL C API
C API Data Structures
C API Function Overview
C API Function Descriptions
C API Prepared Statements
C API Prepared Statement Data Structures
C API Prepared Statement Function Overview
C API Prepared Statement Function Descriptions
C API Threaded Function Descriptions
C API Embedded Server Function Descriptions
C API Client Plugin Functions
Common Questions and Problems When Using the C API
Controlling Automatic Reconnection Behavior
C API Support for Multiple Statement Execution
C API Prepared Statement Problems
C API Prepared Statement Handling of Date and Time Values
C API Support for Prepared CALL Statements
Building Client Programs
MySQL PHP API
Original MariaDB API (MariaDB)
MySQL Improved Extension (Mysqli)
MySQL Native Driver (Mysqlnd)
MySQL Functions (PDO_MYSQL) (MySQL (PDO))
Connector/PHP
Common Problems with MariaDB and PHP
Enabling Both MariaDB and mysqli in PHP
MySQL Perl API
MySQL Python API
MySQL Ruby APIs
The MySQL/Ruby API
The Ruby/MySQL API
MySQL Tcl API
MySQL Eiffel Wrapper

MySQL Connectors provide connectivity to the MariaDB server for client programs. APIs provide low-level access to the MariaDB protocol and MariaDB resources. Both Connectors and the APIs enable you to connect and execute MariaDB statements from another language or environment, including Java (JDBC), ODBC, Perl, Python, PHP, Ruby, and native C and embedded MariaDB instances.Note

Connector version numbers do not correlate with MariaDB Server version numbers. See also Table 20.2, "MySQL Connector Versions and MariaDB Server Versions".

A number of connectors are developed by MySQL:

There are two direct access methods for using MariaDB natively within a C application:

If you need to access MariaDB from a C application, or build an interface to MariaDB for a language not supported by the Connectors or APIs in this chapter, the C API is where you would start. A number of programmers utilities are available to help with the process, and also covered in this section.

The remaining APIs provide an interface to MariaDB from specific application languages. These solutions are not developed or supported by MySQL. Basic information on their usage and abilities is provided here for reference purposes only.

All the language APIs are developed using one of two methods, using libmysql or by building a native driver. The two solutions offer different benefits:

A list of many of the libraries and interfaces available for MariaDB are shown in the table. See Table 20.1, "MySQL APIs and Interfaces".

Table 20.1. MariaDB APIs and Interfaces

Environment API Type Notes
Ada MySQL Bindings for GNU Ada libmysql See MySQL Bindings for GNU Ada
C Connector/C Replacement for libmysql See , "MySQL Connector/C".
C++ Connector/C++ libmysql See , "MySQL Connector/C++".
MySQL++ libmysql See MySQL++ Web site.
MySQL wrapped libmysql See MySQL wrapped.
Cocoa MySQL-Cocoa libmysql Compatible with the Objective-C Cocoa environment. See http://mysql-cocoa.sourceforge.net/
D MySQL for D libmysql See MySQL for D.
Eiffel Eiffel MySQL libmysql See , "MySQL Eiffel Wrapper".
Erlang erlang-mysql-driver libmysql See erlang-mysql-driver.
Haskell Haskell MariaDB Bindings Native Driver See Brian O'Sullivan's pure Haskell MariaDB bindings.
hsql-mysql libmysql See MySQL driver for Haskell .
Java/JDBC Connector/J Native Driver See , "MySQL Connector/J".
Kaya MyDB libmysql See MyDB.
Lua LuaSQL libmysql See LuaSQL.
.NET/Mono Connector/Net Native Driver See , "MySQL Connector/Net".
Objective Caml MySQL Bindings for OBjective Caml libmysql See MySQL Bindings for Objective Caml.
Octave Database bindings for GNU Octave libmysql See Database bindings for GNU Octave.
ODBC Connector/ODBC libmysql See , "MySQL Connector/ODBC".
OpenOffice MySQL Connector/OpenOffice.org libmysql Direct connectivity, without using JDBC/ODBC. See , "MySQL Connector/OpenOffice.org".
Perl DBI/DBD::mysql libmysql See , "MySQL Perl API".
Net::MySQL Native Driver See Net::MySQL at CPAN
PHP MariaDB, ext/mysql interface (deprecated) libmysql See , "Original MariaDB API (MariaDB)".
mysqli, ext/mysqli interface libmysql See , "MySQL Improved Extension (Mysqli)".
PDO_MYSQL libmysql See , "MySQL Functions (PDO_MYSQL) (MySQL (PDO))".
PDO mysqlnd Native Driver See PHP PDO mysqlnd.
Python MySQLdb libmysql See , "MySQL Python API".
Ruby MySQL/Ruby libmysql Uses libmysql. See , "The MySQL/Ruby API".
Ruby/MySQL Native Driver See , "The Ruby/MySQL API".
Scheme Myscsh libmysql See Myscsh.
SPL sql_mysql libmysql See sql_mysql for SPL.
Tcl MySQLtcl libmysql See , "MySQL Tcl API".

Table 20.2. MariaDB Connector Versions and MariaDB Server Versions

Connector Connector version MySQL Server version
Connector/C++ GA 5.6, 5.5, 5.4, 5.1
Connector/J 5.1.8 5.6, 5.5, 5.4, 5.1, 5.0, 4.1
Connector/Net 6.5 5.6, 5.5, 5.4, 5.1, 5.0
Connector/Net 6.4 5.6, 5.5, 5.4, 5.1, 5.0
Connector/Net 6.3 5.6, 5.5, 5.4, 5.1, 5.0
Connector/Net (No longer supported) 5.6, 5.5, 5.4, 5.1, 5.0
Connector/Net (No longer supported) 5.6, 5.5, 5.4, 5.1, 5.0
Connector/Net (No longer supported) 5.6, 5.5, 5.4, 5.1, 5.0
Connector/Net (No longer supported) 5.6, 5.5, 5.4, 5.1, 5.0
Connector/Net (No longer supported) 5.0, 4.0
Connector/ODBC 5.1 5.6, 5.5, 5.4, 5.1, 5.0, 4.1.1+
Connector/ODBC (Unicode not supported) 5.6, 5.5, 5.4, 5.1, 5.0, 4.1
Connector/OpenOffice.org GA 5.6, 5.5, 5.4, 5.1, 5.0

MySQL Connector/ODBC

Connector/ODBC Versions
Connector/ODBC Introduction
Connector/ODBC Installation
Connector/ODBC Configuration
Connector/ODBC Examples
Connector/ODBC Reference
Connector/ODBC Notes and Tips
Connector/ODBC Support

The MariaDB Connector/ODBC is the name for the family of MariaDB ODBC drivers (previously called MyODBC drivers) that provide access to a MariaDB database using the industry standard Open Database Connectivity (ODBC) API. This reference covers Connector/ODBC 3.51 and Connector/ODBC 5.1. Both releases provide an ODBC compliant interface to MariaDB Server.

MySQL Connector/ODBC provides both driver-manager based and native interfaces to the MariaDB database, with full support for MariaDB functionality, including stored procedures, transactions and, with Connector/ODBC 5.1, full Unicode compliance.

For more information on the ODBC API standard and how to use it, refer to http://support.microsoft.com/kb/110093.

The application development section of the ODBC API reference assumes a good working knowledge of C, general DBMS, and a familiarity with MySQL. For more information about MariaDB functionality and its syntax, refer to http://dev.mysql.com/doc/.

Typically, you need to install Connector/ODBC only on Windows machines. For Unix and Mac OS X, you can use the native MariaDB network or named pipe to communicate with your MariaDB database. You may need Connector/ODBC for Unix or Mac OS X if you have an application that requires an ODBC interface to communicate with the database. Applications that require ODBC to communicate with MariaDB include ColdFusion, Microsoft Office, and Filemaker Pro.

Key connector/ODBC topics include:

Connector/ODBC Versions

There are currently two version of Connector/ODBC available:

The manual for versions of Connector/ODBC older than 3.51 can be located in the corresponding binary or source distribution. Please note that versions of Connector/ODBC earlier than the 3.51 revision were not fully compliant with the ODBC specification.Note

From this section onward, the primary focus of this guide is the Connector/ODBC 3.51 and Connector/ODBC 5.1 drivers.Note

Version numbers for MariaDB products are formatted as X.X.X. However, Windows tools (Control Panel, properties display) may show the version numbers as XX.XX.XX. For example, the official MariaDB formatted version number 5.0.9 may be displayed by Windows tools as 5.00.09. The two versions are the same; only the number display format is different.

Connector/ODBC Introduction

General Information About ODBC and Connector/ODBC

ODBC (Open Database Connectivity) provides a way for client programs to access a wide range of databases or data sources. ODBC is a standardized API that enables connections to SQL database servers. It was developed according to the specifications of the SQL Access Group and defines a set of function calls, error codes, and data types that can be used to develop database-independent applications. ODBC usually is used when database independence or simultaneous access to different data sources is required.

For more information about ODBC, refer to http://support.microsoft.com/kb/110093.

General Information About ODBC and Connector/ODBC

Connector/ODBC Architecture
ODBC Driver Managers

Open Database Connectivity (ODBC) is a widely accepted application-programming interface (API) for database access. It is based on the Call-Level Interface (CLI) specifications from X/Open and ISO/IEC for database APIs and uses Structured Query Language (SQL) as its database access language.

A survey of ODBC functions supported by Connector/ODBC is given at , "Connector/ODBC API Reference". For general information about ODBC, see http://support.microsoft.com/kb/110093.

Connector/ODBC Architecture

The Connector/ODBC architecture is based on five components, as shown in the following diagram:Connector/ODBC Architecture

ODBC Driver Managers

An ODBC Driver Manager is a library that manages communication between the ODBC-aware application and any drivers. Its main functionality includes:

Both Windows and Mac OS X include ODBC driver managers with the operating system. Most ODBC Driver Manager implementations also include an administration application that makes the configuration of DSN and drivers easier. Examples and information on these managers, including Unix ODBC driver managers are listed below:

Connector/ODBC Installation

Installing Connector/ODBC from a Binary Distribution on Windows
Installing Connector/ODBC from a Binary Distribution on Unix
Installing Connector/ODBC from a Binary Distribution on Mac OS X
Installing Connector/ODBC from a Source Distribution on Windows
Installing Connector/ODBC from a Source Distribution on Unix
Installing Connector/ODBC from the Development Source Tree

You can install the Connector/ODBC drivers using two different methods, a binary installation and a source installation. The binary installation is the easiest and most straightforward method of installation. Use the source installation methods on platforms where a binary installation package is not available, or in situations where you want to customize or modify the installation process or Connector/ODBC drivers before installation.

Where to Get Connector/ODBC

You can get a copy of the latest version of Connector/ODBC binaries and sources from our Web site at http://dev.mysql.com/downloads/connector/odbc/.

For more information about Connector/ODBC, visit http://www.mysql.com/products/myodbc/.

For more information about licensing, visit http://www.mysql.com/company/legal/licensing/.

Supported Platforms

Connector/ODBC can be used on all major platforms supported by MySQL. You can install it on:

Using a binary distribution offers the most straightforward method for installing Connector/ODBC. If you want more control over the driver, the installation location and or to customize elements of the driver you will need to build and install from the source.

If a binary distribution is not available for a particular platform build the driver from the original source code. You can contribute the binaries you create to MariaDB by sending a mail message to <myodbc@lists.mysql.com>, so that it becomes available for other users.Note

On all non-Windows platforms except Mac OS X, the driver is built against unixODBC and is expecting a 2-byte SQLWCHAR, not 4 bytes as iODBC is using. For this reason, the binaries are only compatible with unixODBC and you will need to recompile the driver against iODBC to use them together. For further information see , "ODBC Driver Managers".

For further instructions:

Platform Binary Source
Windows Installation Instructions Build Instructions
Unix/Linux Installation Instructions Build Instructions
Mac OS X Installation Instructions

Installing Connector/ODBC from a Binary Distribution on Windows

Installing the Windows Connector/ODBC Driver using an installer
Installing the Windows Connector/ODBC Driver using the Zipped DLL package

Before installing the Connector/ODBC drivers on Windows, ensure that your Microsoft Data Access Components (MDAC) are up to date. You can obtain the latest version from the Microsoft Data Access and Storage Web site.

There are three available distribution types to use when installing for Windows. The contents in each case are identical, it is only the installation method which is different.

Note

An OLEDB/ODBC driver for Windows 64-bit is available from Microsoft Downloads.

Installing the Windows Connector/ODBC Driver using an installer

The installer packages offer a very simple method for installing the Connector/ODBC drivers. If you have downloaded the zipped installer then you must extract the installer application. The basic installation process is identical for both installers.

Follow these steps to complete the installation:

  1. Double-click the standalone installer that you extracted, or the MSI file you downloaded.
  2. The MariaDB Connector/ODBC 3.51 - Setup Wizard will start. Click the Next button to begin the installation process.Connector/ODBC Windows Installer - Welcome
  3. You will need to choose the installation type. The Typical installation provides the standard files you will need to connect to a MariaDB database using ODBC. The Complete option installs all the available files, including debug and utility components. It is recommended you choose one of these two options to complete the installation. If choose one of these methods, click Next and then proceed to step 5.

    You can also choose a Custom installation, which enables you to select the individual components to install. You have chosen this method, click Next and then proceed to step 4.Connector/ODBC Windows Installer - Choosing a Setup type welcome

  4. If you have chosen a custom installation, use the pop-ups to select which components to install and then click Next to install the necessary files.Connector/ODBC Windows Installer - Custom Installation welcome
  5. Once the files have copied to your machine, the installation is complete. Click Finish to exit the installer.Connector/ODBC Windows Installer - Completion welcome

Now the installation is complete, you can continue to configure your ODBC connections using , "Connector/ODBC Configuration".

Installing the Windows Connector/ODBC Driver using the Zipped DLL package

If you have downloaded the Zipped DLL package then you must install the individual files required for Connector/ODBC operation manually. Once you have unzipped the installation files, you can either perform this operation by hand, executing each statement individually, or you can use the included Batch file to perform an installation to the default locations.Note

The following instructions will only work for 32-bit Windows systems. If you have a 64-bit Windows system you are advised to use the MSI installer, which will install both the 32-bit and 64-bit drivers to the correct locations.

To install using the Batch file:

  1. Unzip the Connector/ODBC Zipped DLL package.
  2. Open a Command Prompt.
  3. Change to the directory created when you unzipped the Connector/ODBC Zipped DLL package.
  4. Run Install.bat: 
    C:\> Install.bat

    This will copy the necessary files into the default location, and then register the Connector/ODBC driver with the Windows ODBC manager.

Note

Changing or adding a new DSN (data source name) may be accomplished using either the GUI, or from the command-line using myodbc3i.exe with Connector/ODBC 3.51, or myodbc-installer.exe with Connector/ODBC 5.1.

To copy the files to an alternative location - for example, to run or test different versions of the Connector/ODBC driver on the same machine, then you must copy the files by hand. It is however not recommended to install these files in a nonstandard location. To copy the files by hand to the default installation location, use the following steps:

  1. Unzip the Connector/ODBC Zipped DLL package.
  2. Open a Command Prompt.
  3. Change to the directory created when you unzipped the Connector/ODBC Zipped DLL package.
  4. Copy the library files to a suitable directory. The default is to copy them into the default Windows system directory \Windows\System32: 
    C:\> copy lib\myodbc3S.dll \Windows\System32
C:\> copy lib\myodbc3S.lib \Windows\System32
C:\> copy lib\myodbc3.dll \Windows\System32
C:\> copy lib\myodbc3.lib \Windows\System32
  5. Copy the Connector/ODBC tools. These must be placed into a directory that is in the system PATH. The default is to install these into the Windows system directory \Windows\System32: 
    C:\> copy bin\myodbc3i.exe \Windows\System32
C:\> copy bin\myodbc3m.exe \Windows\System32
C:\> copy bin\myodbc3c.exe \Windows\System32
  6. Optionally copy the help files. For these files to be accessible through the help system, they must be installed in the Windows system directory: 
    C:\> copy doc\*.hlp \Windows\System32
  7. Finally, you must register the Connector/ODBC driver with the ODBC manager: 
    C:\> myodbc3i -a -d -t'MySQL ODBC 3.51 Driver;\
 DRIVER=myodbc3.dll;SETUP=myodbc3S.dll'

    You must change the references to the DLL files and command location in the above statement if you have not installed these files into the default location.

Installing Connector/ODBC from a Binary Distribution on Unix

Installing Connector/ODBC from a Binary Tarball Distribution
Installing Connector/ODBC from an RPM Distribution

There are two methods available for installing Connector/ODBC on Unix from a binary distribution. For most Unix environments you will need to use the tarball distribution. For Linux systems, there is also an RPM distribution available.Note

To install Connector/ODBC 5.1 on Unix you require unixODBC 2.2.12 or later to be installed.

Installing Connector/ODBC from a Binary Tarball Distribution

To install the driver from a tarball distribution (.tar.gz file), download the latest version of the driver for your operating system and follow these steps that demonstrate the process using the Linux version of the tarball: 

shell> su root
shell> gunzip mysql-connector-odbc-3.51.11-i686-pc-linux.tar.gz
shell> tar xvf mysql-connector-odbc-3.51.11-i686-pc-linux.tar
shell> cd mysql-connector-odbc-3.51.11-i686-pc-linux

Read the installation instructions in the INSTALL file and execute these commands.

Then proceed on to , "Configuring a Connector/ODBC DSN on Unix", to configure the DSN for Connector/ODBC. For more information, refer to the INSTALL file that comes with your distribution.

Installing Connector/ODBC from an RPM Distribution

To install or upgrade Connector/ODBC from an RPM distribution on Linux, simply download the RPM distribution of the latest version of Connector/ODBC and follow the instructions below. Use su root to become root, then install the RPM file.

If you are installing for the first time: 

shell> su root
 shell> rpm -ivh mysql-connector-odbc-3.51.12.i386.rpm

If the driver exists, upgrade it like this: 

shell> su root
shell> rpm -Uvh mysql-connector-odbc-3.51.12.i386.rpm

If there is any dependency error for MariaDB client library, libmysqlclient, simply ignore it by supplying the --nodeps option, and then make sure the MariaDB client shared library is in the path or set through LD_LIBRARY_PATH.

This installs the driver libraries and related documents to /usr/local/lib and /usr/share/doc/MyODBC, respectively. Proceed onto , "Configuring a Connector/ODBC DSN on Unix".

To uninstall the driver, become root and execute an rpm command: 

shell> su root
shell> rpm -e mysql-connector-odbc

Installing Connector/ODBC from a Binary Distribution on Mac OS X

Mac OS X is based on the FreeBSD operating system, and you can normally use the MariaDB network port for connecting to MariaDB servers on other hosts. Installing the Connector/ODBC driver lets you connect to MariaDB databases on any platform through the ODBC interface. If your application requires an ODBC interface, install the Connector/ODBC driver. Applications that require or can use ODBC (and therefore the Connector/ODBC driver) include ColdFusion, Filemaker Pro, 4th Dimension and many other applications.

Mac OS X includes its own ODBC manager, based on the iODBC manager. Mac OS X includes an administration tool that provides easier administration of ODBC drivers and configuration, updating the underlying iODBC configuration files.

The method for installing Connector/ODBC on Mac OS X depends on the version on Connector/ODBC you are using. For Connector/ODBC 3.51.14 and later, the package is provided as a compressed tar archive that you must manually install. For Connector/ODBC 3.51.13 and earlier the software was provided on a compressed disk image (.dmg) file and included an installer.

In either case, the driver is designed to work with the iODBC driver manager included with Mac OS X.

To install Connector/ODBC 3.51.14 and later:

  1. Download the installation file. Note that versions are available for both PowerPC and Intel platforms.
  2. Extract the archive: 
    shell> tar zxf mysql-connector-odbc-3.51.16-osx10.4-x86-32bit.tar.gz
  3. The directory created will contain two subdirectories, lib and bin. You need to copy these to a suitable location such as /usr/local: 
    shell> cp bin/* /usr/local/bin shell> cp lib/* /usr/local/lib
  4. Finally, you must register the driver with iODBC using the myodbc3i tool you just installed: 
    shell> myodbc3i -a -d -t'MySQL ODBC 3.51 Driver;Driver=/usr/local/lib/libmyodbc3.so;Setup=/usr/local/lib/libmyodbc3S.so'

You can verify the installed drivers either by using the ODBC Administrator application or the myodbc3i utility: 

shell> myodbc3i -q -d

To install Connector/ODBC 3.51.13 and earlier, follow these steps:

  1. Download the file to your computer and double-click the downloaded image file.
  2. Within the disk image you will find an installer package (with the .pkg extension). Double-click on this file to start the Mac OS X installer.
  3. You will be presented with the installer welcome message. Click the Continue button to begin the installation process.Connector/ODBC Mac OS X Installer - Installer welcome
  4. Please take the time to read the Important Information as it contains guidance on how to complete the installation process. Once you have read the notice and collected the necessary information, click Continue.Connector/ODBC Mac OS X Installer - Important Information
  5. Connector/ODBC drivers are made available under the GNU General Public License. Please read the license if you are not familiar with it before continuing installation. Click Continue to approve the license (you will be asked to confirm that decision) and continue the installation.Connector/ODBC Mac OS X Installer - License
  6. Choose a location to install the Connector/ODBC drivers and the ODBC Administrator application. You must install the files onto a drive with an operating system and you may be limited in the choices available. Select the drive you want to use, and then click Continue.Connector/ODBC Mac OS X Installer - Choosing a destination
  7. The installer will automatically select the files that need to be installed on your machine. Click Install to continue. The installer will copy the necessary files to your machine. A progress bar will be shown indicating the installation progress.Connector/ODBC Mac OS X Installer - Installation type
  8. When installation has been completed you will get a window like the one shown below. Click Close to close and quit the installer.Connector/ODBC Mac OS X Installer - Installation complete

Installing Connector/ODBC from a Source Distribution on Windows

Building Connector/ODBC 5.1
Building Connector/ODBC 3.51

You only need to install Connector/ODBC from source on Windows to change or modify the source or installation. If you are unsure whether to install from source, please use the binary installation detailed in , "Installing Connector/ODBC from a Binary Distribution on Windows".

Installing Connector/ODBC from source on Windows requires a number of different tools and packages:

Building Connector/ODBC 5.1

You need to have the environment variables set for the Visual Studio toolchain. Visual Studio includes a batch file to set these for you, and installs a Start menu shortcut that opens a command prompt with these variables set.

You need to set MYSQL_DIR to the MariaDB server installation path, while using the short-style file names. For example: 

C:\> set MYSQL_DIR=C:\PROGRA~1\MySQL\MYSQLS~1.0

Build Connector/ODBC using the 'cmake' command-line tool by executing the following from the source root directory (in a command prompt window): 

C:\> cmake -G 'Visual Studio 8 2005'

This produces a project file that you can open with Visual Studio, or build from the command line with either of the following commands: 

C:\> devenv.com MySQL_Connector_ODBC.sln /build Release
C:\> devenv.com MySQL_Connector_ODBC.sln /build RelWithDebInfo

To compile the 'Debug' build, you must set the cmake build type so that the correct version of the MariaDB client libraries are used: 

C:\> cmake -G 'Visual Studio 8 2005' -DCMAKE_BUILD_TYPE=Debug
C:\> devenv.com MySQL_Connector_ODBC.sln /build Debug

Upon completion, you will find the executables in the bin/ and lib/ sub-directories.

See , "Installing the Windows Connector/ODBC Driver using the Zipped DLL package" to complete the installation.

Building Connector/ODBC 3.51

Connector/ODBC source distributions include Makefiles that require the nmake or other make utility. In the distribution, you can find Makefile for building the release version and Makefile_debug for building debugging versions of the driver libraries and DLLs.

To build the driver, use this procedure:

  1. Download and extract the sources to a folder, then change directory into that folder. The following command assumes the folder is named myodbc3-src: 

    C:\> cd myodbc3-src
  2. Edit Makefile to specify the correct path for the MariaDB client libraries and header files. Then use the following commands to build and install the release version: 
    C:\> nmake -f Makefile
C:\> nmake -f Makefile install

    nmake -f Makefile builds the release version of the driver and places the binaries in subdirectory called Release.

    nmake -f Makefile install installs (copies) the driver DLLs and libraries (myodbc3.dll, myodbc3.lib) to your system directory.

  3. To build the debug version, use Makefile_Debug rather than Makefile, as shown below: 
    C:\> nmake -f Makefile_debug
C:\> nmake -f Makefile_debug install
  4. You can clean and rebuild the driver by using: 
    C:\> nmake -f Makefile clean
C:\> nmake -f Makefile install
Note

After the driver libraries are copied/installed to the system directory, you can test whether the libraries are properly built by using the samples provided in the samples subdirectory: 

C:\> cd samples
C:\> nmake -f Makefile all

Installing Connector/ODBC from a Source Distribution on Unix

Typical cmake Options
Typical configure Options
Additional configure Options
Building and Compilation
Building Shared Libraries
Installing Driver Libraries
Testing Connector/ODBC on Unix
Building Connector/ODBC from Source on Mac OS X
Building Connector/ODBC from Source on HP-UX
Building Connector/ODBC from Source on AIX
Note

As of Connector/5.1.9, the build system on Linux changed, and now uses CMake instead of autoconf (configure). The manual refers to both methods.

You need the following tools to build MariaDB from source on Unix:

Once you have all the required files, unpack the source files to a separate directory, you then have to run configure and build the library using make.

Typical cmake Options

CMake support on Unix exists as of Connector/ODBC 5.1.9.

iODBC is the default ODBC library used by Connector/ODBC. Alternatively, unixODBC may be used by passing in the appropriate option to CMake. For example: 

shell> cmake -G 'Unix Makefiles' -DWITH_UNIXODBC=1

When you run cmake, you might add options to the command line. Here are some examples:

Typical configure Options

autoconf (configure) is supported on Unix in Connector/ODBC 5.1.8 and below.

The configure script gives you a great deal of control over how you configure your Connector/ODBC build. Typically you do this using options on the configure command line. You can also affect configure using certain environment variables. For a list of options and environment variables supported by configure, run this command: 

shell> ./configure --help

Some of the more commonly used configure options are described here:

  1. To compile Connector/ODBC, you need to supply the MariaDB client include and library files path using the --with-mysql-path=DIR option, where DIR is the directory where MariaDB is installed.

    MySQL compile options can be determined by running DIR/bin/mysql_config.

  2. Supply the standard header and library files path for your ODBC Driver Manager (iODBC or unixODBC).
    • If you are using iODBC and iODBC is not installed in its default location (/usr/local), you might have to use the --with-iodbc=DIR option, where DIR is the directory where iODBC is installed.

      If the iODBC headers do not reside in DIR/include, you can use the --with-iodbc-includes=INCDIR option to specify their location.

      The applies to libraries. If they are not in DIR/lib, you can use the --with-iodbc-libs=LIBDIR option.

    • If you are using unixODBC, use the --with-unixODBC=DIR option (case sensitive) to make configure look for unixODBC instead of iODBC by default, DIR is the directory where unixODBC is installed.

      If the unixODBC headers and libraries aren't located in DIR/include and DIR/lib, use the --with-unixODBC-includes=INCDIR and --with-unixODBC-libs=LIBDIR options.

  3. You might specify an installation prefix other than /usr/local. For example, to install the Connector/ODBC drivers in /usr/local/odbc/lib, use the --prefix=/usr/local/odbc option.

The final configuration command looks something like this: 

shell> ./configure --prefix=/usr/local \
 --with-iodbc=/usr/local \
 --with-mysql-path=/usr/local/mysql
Additional configure Options

There are a number of other options that you need, or want, to set when configuring the Connector/ODBC driver before it is built.

Building and Compilation

To build the driver libraries, you have to just execute make. 

shell> make

If any errors occur, correct them and continue the build process. If you aren't able to build, then send a detailed email to <myodbc@lists.mysql.com> for further assistance.

Building Shared Libraries

On most platforms, MariaDB does not build or support .so (shared) client libraries by default. This is based on our experience of problems when building shared libraries.

In cases like this, you have to download the MariaDB distribution and configure it with these options: 

--without-server --enable-shared

To build shared driver libraries, you must specify the --enable-shared option for configure. By default, configure does not enable this option.

If you have configured with the --disable-shared option, you can build the .so file from the static libraries using the following commands: 

shell> cd mysql-connector-odbc-3.51.01
shell> make
shell> cd driver
shell> CC=/usr/bin/gcc \
 $CC -bundle -flat_namespace -undefined error \
 -o .libs/libmyodbc3-3.51.01.so \
 catalog.o connect.o cursor.o dll.o error.o execute.o \
 handle.o info.o misc.o myodbc3.o options.o prepare.o \
 results.o transact.o utility.o \
 -L/usr/local/mysql/lib/mysql/ \
 -L/usr/local/iodbc/lib/ \
 -lz -lc -lmysqlclient -liodbcinst

Make sure to change -liodbcinst to -lodbcinst if you are using unixODBC instead of iODBC, and configure the library paths accordingly.

This builds and places the libmyodbc3-3.51.01.so file in the .libs directory. Copy this file to the Connector/ODBC library installation directory (/usr/local/lib (or the lib directory under the installation directory that you supplied with the --prefix). 

shell> cd .libs
shell> cp libmyodbc3-3.51.01.so /usr/local/lib
shell> cd /usr/local/lib
shell> ln -s libmyodbc3-3.51.01.so libmyodbc3.so

To build the thread-safe driver library: 

shell> CC=/usr/bin/gcc \
 $CC -bundle -flat_namespace -undefined error
 -o .libs/libmyodbc3_r-3.51.01.so
 catalog.o connect.o cursor.o dll.o error.o execute.o
 handle.o info.o misc.o myodbc3.o options.o prepare.o
 results.o transact.o utility.o
 -L/usr/local/mysql/lib/mysql/
 -L/usr/local/iodbc/lib/
 -lz -lc -lmysqlclient_r -liodbcinst
Installing Driver Libraries

To install the driver libraries, execute the following command: 

shell> make install

That command installs one of the following sets of libraries:

For Connector/ODBC 3.51:

For thread-safe Connector/ODBC 3.51:

For more information on build process, refer to the INSTALL file that comes with the source distribution. Note that if you are trying to use the make from Sun, you may end up with errors. On the other hand, GNU gmake should work fine on all platforms.

Testing Connector/ODBC on Unix

To run the basic samples provided in the distribution with the libraries that you built, use the following command: 

shell> make test

Before running the tests, create the DSN 'myodbc3' in odbc.ini and set the environment variable ODBCINI to the correct odbc.ini file; and MariaDB server is running. You can find a sample odbc.ini with the driver distribution.

You can even modify the samples/run-samples script to pass the desired DSN, UID, and PASSWORD values as the command-line arguments to each sample.

Building Connector/ODBC from Source on Mac OS X

To build the driver on Mac OS X (Darwin), make use of the following configure example: 

shell> ./configure --prefix=/usr/local
 --with-unixODBC=/usr/local
 --with-mysql-path=/usr/local/mysql
 --disable-shared
 --enable-gui=no
 --host=powerpc-apple

The command assumes that the unixODBC and MariaDB are installed in the default locations. If not, configure accordingly.

On Mac OS X, --enable-shared builds .dylib files by default. You can build .so files like this: 

shell> make
shell> cd driver
shell> CC=/usr/bin/gcc \
 $CC -bundle -flat_namespace -undefined error
 -o .libs/libmyodbc3-3.51.01.so *.o
 -L/usr/local/mysql/lib/
 -L/usr/local/iodbc/lib
 -liodbcinst -lmysqlclient -lz -lc

To build the thread-safe driver library: 

shell> CC=/usr/bin/gcc \
 $CC -bundle -flat_namespace -undefined error
 -o .libs/libmyodbc3-3.51.01.so *.o
 -L/usr/local/mysql/lib/
 -L/usr/local/iodbc/lib
 -liodbcinst -lmysqlclienti_r -lz -lc -lpthread

Make sure to change the -liodbcinst to -lodbcinst in case of using unixODBC instead of iODBC and configure the libraries path accordingly.

In Apple's version of GCC, both cc and gcc are actually symbolic links to gcc3.

Copy this library to the $prefix/lib directory and symlink to libmyodbc3.so.

You can cross-check the output shared-library properties using this command: 

shell> otool -LD .libs/libmyodbc3-3.51.01.so
Building Connector/ODBC from Source on HP-UX

To build the driver on HP-UX 10.x or 11.x, make use of the following configure example:

If using cc: 

shell> CC='cc' \
 CFLAGS='+z' \
 LDFLAGS='-Wl,+b:-Wl,+s' \
 ./configure --prefix=/usr/local
 --with-unixodbc=/usr/local
 --with-mysql-path=/usr/local/mysql/lib/mysql
 --enable-shared
 --enable-thread-safe

If using gcc: 

shell> CC='gcc' \
 LDFLAGS='-Wl,+b:-Wl,+s' \
 ./configure --prefix=/usr/local
 --with-unixodbc=/usr/local
 --with-mysql-path=/usr/local/mysql
 --enable-shared
 --enable-thread-safe

Once the driver is built, cross-check its attributes using chatr .libs/libmyodbc3.sl to determine whether you need to have set the MariaDB client library path using the SHLIB_PATH environment variable. For static versions, ignore all shared-library options and run configure with the --disable-shared option.

Building Connector/ODBC from Source on AIX

To build the driver on AIX, make use of the following configure example: 

shell> ./configure --prefix=/usr/local
 --with-unixodbc=/usr/local
 --with-mysql-path=/usr/local/mysql
 --disable-shared
 --enable-thread-safe
Note

For more information about how to build and set up the static and shared libraries across the different platforms refer to ' Using static and shared libraries across platforms'.

Installing Connector/ODBC from the Development Source Tree

Caution

Read this section only if you are interested in helping us test our new code. To just get MariaDB Connector/ODBC up and running on your system, use a standard release distribution.

To obtain the most recent development source tree, first download and install Bazaar from the Bazaar VCS Web site. Bazaar is supported by any platform that supports Python, and is therefore compatible with any Linux, Unix, Windows or Mac OS X host. Instructions for downloading and installing Bazaar on the different platforms are available on the Bazaar Web site.

Build from the source trees requires the following tools:

The most recent development source tree is available from our public Subversion trees at http://dev.mysql.com/tech-resources/sources.html.

To check out out the Connector/ODBC sources, change to the directory where you want the copy of the Connector/ODBC tree to be stored, then use the following command: 

shell> bzr branch lp:myodbc

You should now have a copy of the entire Connector/ODBC source tree in the directory connector-odbc3. To build from this source tree on Unix or Linux, follow these steps: 

shell> cd myodbc
shell> aclocal
shell> autoheader
shell> libtoolize -c -f
shell> autoconf
shell> automake;
shell> ./configure # Add your favorite options here
shell> make

For more information on how to build, refer to the INSTALL file located in the same directory. For more information on options to configure, see , "Typical configure Options"

When the build is done, run make install to install the Connector/ODBC 3.51 driver on your system.

If you have gotten to the make stage and the distribution does not compile, please report it to <myodbc@lists.mysql.com>.

On Windows, make use of Windows Makefiles WIN-Makefile and WIN-Makefile_debug in building the driver. For more information, see , "Installing Connector/ODBC from a Source Distribution on Windows".

After the initial checkout operation to get the source tree, run bzr pull periodically to update your source according to the latest version.

Connector/ODBC Configuration

Data Source Names
Connector/ODBC Connection Parameters
Configuring a Connector/ODBC DSN on Windows
Configuring a Connector/ODBC DSN on Mac OS X
Configuring a Connector/ODBC DSN on Unix
Connecting Without a Predefined DSN
ODBC Connection Pooling
Getting an ODBC Trace File

Before you connect to a MariaDB database using the Connector/ODBC driver you must configure an ODBC Data Source Name. The DSN associates the various configuration parameters required to communicate with a database to a specific name. You use the DSN in an application to communicate with the database, rather than specifying individual parameters within the application itself. DSN information can be user specific, system specific, or provided in a special file. ODBC data source names are configured in different ways, depending on your platform and ODBC driver.

Data Source Names

A Data Source Name associates the configuration parameters for communicating with a specific database. Generally a DSN consists of the following parameters:

In addition, different ODBC drivers, including Connector/ODBC, may accept additional driver-specific options and parameters.

There are three types of DSN:

DSN information is stored in different locations depending on your platform and environment.

Connector/ODBC Connection Parameters

You can specify the parameters in the following tables for Connector/ODBC when configuring a DSN:

Users on Windows can use the Options and Advanced panels when configuring a DSN to set these parameters; see the table for information on which options relate to which fields and check boxes. On Unix and Mac OS X, use the parameter name and value as the keyword/value pair in the DSN configuration. Alternatively, you can set these parameters within the InConnectionString argument in the SQLDriverConnect() call.

Table 20.3. Connector/ODBC DSN Configuration Options

Parameter Default Value Comment
user ODBC The user name used to connect to MariaDB.
uid ODBC Synonymous with user. Added in 3.51.16.
server localhost The host name of the MariaDB server.
database The default database.
option 0 Options that specify how Connector/ODBC works. See below.
port 3306 The TCP/IP port to use if server is not localhost.
initstmt Initial statement. A statement to execute when connecting to MariaDB. In version 3.51 the parameter is called stmt. Note, the driver supports the initial statement being executed only at the time of the initial connection.
password The password for the user account on server.
pwd Synonymous with password. Added in 3.51.16.
socket The Unix socket file or Windows named pipe to connect to if server is localhost.
sslca The path to a file with a list of trust SSL CAs. Added in 3.51.16.
sslcapath The path to a directory that contains trusted SSL CA certificates in PEM format. Added in 3.51.16.
sslcert The name of the SSL certificate file to use for establishing a secure connection. Added in 3.51.16.
sslcipher A list of permissible ciphers to use for SSL encryption. The cipher list has the same format as the openssl ciphers command Added in 3.51.16.
sslkey The name of the SSL key file to use for establishing a secure connection. Added in 3.51.16.
charset The character set to use for the connection. Added in 3.51.17.
sslverify If set to 1, the SSL certificate will be verified when used with the MariaDB connection. If not set, then the default behavior is to ignore SSL certificate verification.
readtimeout The timeout in seconds for attempts to read from the server. Each attempt uses this timeout value and there are retries if necessary, so the total effective timeout value is three times the option value. You can set the value so that a lost connection can be detected earlier than the TCP/IP Close_Wait_Timeout value of 10 minutes. This option works only for TCP/IP connections, and only for Windows prior to MariaDB 5.1.12. Corresponds to the MYSQL_OPT_READ_TIMEOUT option of the MariaDB Client Library. This option was added in Connector/ODBC 3.51.27.
writetimeout The timeout in seconds for attempts to write to the server. Each attempt uses this timeout value and there are net_retry_count retries if necessary, so the total effective timeout value is net_retry_count times the option value. This option works only for TCP/IP connections, and only for Windows prior to MariaDB 5.1.12. Corresponds to the MYSQL_OPT_WRITE_TIMEOUT option of the MariaDB Client Library. This option was added in Connector/ODBC 3.51.27.
interactive Enables the CLIENT_INTERACTIVE connection option of mysql_real_connect.
Note

The SSL configuration parameters can also be automatically loaded from a my.ini or my.cnf file.

The option argument is used to tell Connector/ODBC that the client isn't 100% ODBC compliant. On Windows, you normally select options by toggling the check boxes in the connection screen, but you can also select them in the option argument. The following options are listed in the order in which they appear in the Connector/ODBC connect screen.

Table 20.4. Connector/ODBC Option Flags

Flag Name GUI Option Constant Value Description
FLAG_FIELD_LENGTH Do not Optimize Column Width The client cannot handle that Connector/ODBC returns the real width of a column. This option was removed in 3.51.18.
FLAG_FOUND_ROWS Return Matching Rows 2 The client cannot handle that MariaDB returns the true value of affected rows. If this flag is set, MariaDB returns "found rows" instead. You must have MariaDB 3.21.14 or newer to get this to work.
FLAG_DEBUG Trace Driver Calls To myodbc.log Make a debug log in C:\myodbc.log on Windows, or /tmp/myodbc.log on Unix variants. This option was removed in Connector/ODBC 3.51.18.
FLAG_BIG_PACKETS Allow Big Results 8 Do not set any packet limit for results and bind parameters. Without this option, parameter binding will be truncated to 255 characters.
FLAG_NO_PROMPT Do not Prompt Upon Connect 16 Do not prompt for questions even if driver would like to prompt.
FLAG_DYNAMIC_CURSOR Enable Dynamic Cursor 32 Enable or disable the dynamic cursor support.
FLAG_NO_SCHEMA Ignore # in Table Name 64 Ignore use of database name in db_name.tbl_name.col_name.
FLAG_NO_DEFAULT_CURSOR User Manager Cursors 128 Force use of ODBC manager cursors (experimental).
FLAG_NO_LOCALE Do not Use Set Locale 256 Disable the use of extended fetch (experimental).
FLAG_PAD_SPACE Pad Char To Full Length 512 Pad CHAR columns to full column length.
FLAG_FULL_COLUMN_NAMES Return Table Names for SQLDescribeCol 1024 SQLDescribeCol() returns fully qualified column names.
FLAG_COMPRESSED_PROTO Use Compressed Protocol 2048 Use the compressed client/server protocol.
FLAG_IGNORE_SPACE Ignore Space After Function Names 4096 Tell server to ignore space after function name and before "(" (needed by PowerBuilder). This makes all function names keywords.
FLAG_NAMED_PIPE Force Use of Named Pipes 8192 Connect with named pipes to a mysqld server running on NT.
FLAG_NO_BIGINT Change BIGINT Columns to Int 16384 Change BIGINT columns to INT columns (some applications cannot handle BIGINT).
FLAG_NO_CATALOG No Catalog 32768 Forces results from the catalog functions, such as SQLTables, to always return NULL and the driver to report that catalogs are not supported.
FLAG_USE_MYCNF Read Options From my.cnf 65536 Read parameters from the [client] and [odbc] groups from my.cnf.
FLAG_SAFE Safe 131072 Add some extra safety checks.
FLAG_NO_TRANSACTIONS Disable transactions 262144 Disable transactions.
FLAG_LOG_QUERY Save queries to myodbc.sql 524288 Enable query logging to c:\myodbc.sql(/tmp/myodbc.sql) file. (Enabled only in debug mode.)
FLAG_NO_CACHE Do not Cache Result (forward only cursors) 1048576 Do not cache the results locally in the driver, instead read from server (mysql_use_result()). This works only for forward-only cursors. This option is very important in dealing with large tables when you do not want the driver to cache the entire result set.
FLAG_FORWARD_CURSOR Force Use Of Forward Only Cursors 2097152 Force the use of Forward-only cursor type. In case of applications setting the default static/dynamic cursor type, and one wants the driver to use noncache result sets, then this option ensures the forward-only cursor behavior.
FLAG_AUTO_RECONNECT Enable auto-reconnect. 4194304 Enables auto-reconnection functionality. Do not use this option with transactions, since a auto reconnection during a incomplete transaction may cause corruption. Note that an auto-reconnected connection will not inherit the same settings and environment as the original. This option was added in Connector/ODBC 3.51.13.
FLAG_AUTO_IS_NULL Flag Auto Is Null 8388608 When FLAG_AUTO_IS_NULL is set, the driver does not change the default value of sql_auto_is_null, leaving it at 1, so you get the MariaDB default, not the SQL standard behavior.

When FLAG_AUTO_IS_NULL is not set, the driver changes the default value of SQL_AUTO_IS_NULL to 0 after connecting, so you get the SQL standard, not the MariaDB default behavior.

Thus, omitting the flag disables the compatibility option and forces SQL standard behavior.

See IS NULL. This option was added in Connector/ODBC 3.51.13.

FLAG_ZERO_DATE_TO_MIN Return SQL_NULL_DATA for zero date 16777216 Translates zero dates (XXXX-00-00) into the minimum date values supported by ODBC, XXXX-01-01. This resolves an issue where some statements will not work because the date returned and the minimum ODBC date value are incompatible. This option was added in Connector/ODBC 3.51.17.
FLAG_MIN_DATE_TO_ZERO Bind minimal date as zero date 33554432 Translates the minimum ODBC date value (XXXX-01-01) to the zero date format supported by MariaDB (XXXX-00-00). This resolves an issue where some statements will not work because the date returned and the minimum ODBC date value are incompatible. This option was added in Connector/ODBC 3.51.17.
FLAG_MULTI_STATEMENTS Allow multiple statements 67108864 Enables support for batched statements. This option was added in Connector/ODBC 3.51.18.
FLAG_COLUMN_SIZE_S32 Limit column size to 32-bit value 134217728 Limits the column size to a signed 32-bit value to prevent problems with larger column sizes in applications that do not support them. This option is automatically enabled when working with ADO applications. This option was added in Connector/ODBC 3.51.22.
FLAG_NO_BINARY_RESULT Always handle binary function results as character data 268435456 When set this option disables charset 63 for columns with an empty org_table. This option was added in Connector/ODBC 3.51.26.
FLAG_DFLT_BIGINT_BIND_STR 536870912 Causes BIGINT parameters to be bound as strings. Microsoft Access treats BIGINT as a string on linked tables. The value is read correctly, but bound as a string. This option is used automatically if the driver is used by Microsoft Access.
FLAG_NO_INFORMATION_SCHEMA 1073741824 Tells catalog functions not to use INFORMATION_SCHEMA, but rather use legacy algorithms. The trade-off here is usually speed for information quality. Using INFORMATION_SCHEMA is often slow, but the information obtained is more complete.

To select multiple options, add together their values, using the numbers from the Constant Value column in the table.Note

From version of MariaDB Connector/ODBC 5.1.6 onwards, you can use the flag name directly as a parameter in the connection string, by specifying the flag name without the FLAG_ prefix. So, in addition to using the options parameter with various flags set, it is now possible to use the flags directly as parameters. For example, FIELD_LENGTH, FOUND_ROWS and DEBUG could all be used as parameters.

The following table shows some recommended option values for various configurations.

Configuration Option Value
Microsoft Access, Visual Basic 3
Driver trace generation (Debug mode) 4
Microsoft Access (with improved DELETE queries) 35
Large tables with too many rows 2049
Sybase PowerBuilder 135168
Query log generation (Debug mode) 524288
Generate driver trace as well as query log (Debug mode) 524292
Large tables with no-cache results 3145731

Configuring a Connector/ODBC DSN on Windows

Configuring a Connector/ODBC 3.51 DSN on Windows
Configuring a Connector/ODBC 3.51 DSN on Windows, using the command-line
Configuring a Connector/ODBC 5.1 DSN on Windows
Configuring a Connector/ODBC 5.1 DSN on Windows, using the command-line
Troubleshooting ODBC Connection Problems

The ODBC Data Source Administrator within Windows lets you create DSNs, check driver installation and configure ODBC systems such as tracing (used for debugging) and connection pooling.

Different editions and versions of Windows store the ODBC Data Source Administrator in different locations depending on the version of Windows that you are using.

To open the ODBC Data Source Administrator in Windows Server 2003:Tip

Because it is possible to create DSN using either the 32-bit or 64-bit driver, but using the same DNS identifier, it is advisable to include the driver being used within the DSN identifier. This will help you to identify the DSN when using it from applications such as Excel that are only compatible with the 32-bit driver. For example, you might add Using32bitCODBC to the DSN identifier for the 32-bit interface and Using64bitCODBC for those using the 64-bit Connector/ODBC driver.

  1. On the Start menu, choose Administrative Tools, and then click Data Sources (ODBC).

To open the ODBC Data Source Administrator in Windows 2000 Server or Windows 2000 Professional:

  1. On the Start menu, choose Settings, and then click Control Panel.
  2. In Control Panel, click Administrative Tools.
  3. In Administrative Tools, click Data Sources (ODBC).

To open the ODBC Data Source Administrator on Windows XP:

  1. On the Start menu, click Control Panel.
  2. In the Control Panel when in Category View click Performance and Maintenance and then click Administrative Tools.. If you are viewing the Control Panel in Classic View, click Administrative Tools.
  3. In Administrative Tools, click Data Sources (ODBC).

Irrespective of your Windows version, you should be presented the ODBC Data Source Administrator window:ODBC Data Source Administrator Dialog

Within Windows XP, you can add the Administrative Tools folder to your Start menu to make it easier to locate the ODBC Data Source Administrator. To do this:

  1. Right-click the Start menu.
  2. Select Properties.
  3. Click Customize....
  4. Select the Advanced tab.
  5. Within Start menu items, within the System Administrative Tools section, select Display on the All Programs menu.

Within both Windows Server 2003 and Windows XP, consider permanently adding the ODBC Data Source Administrator to your Start menu. To do this, locate the Data Sources (ODBC) icon using the methods shown, then right-click on the icon and then choose Pin to Start Menu.

The interfaces for the 3.51 and 5.1 versions of the Connector/ODBC driver are different, although the fields and information that you need to enter remain the same.

To configure a DSN using Connector/ODBC 3.51.x or Connector/ODBC 5.1.0, see , "Configuring a Connector/ODBC 3.51 DSN on Windows".

To configure a DSN using Connector/ODBC 5.1.1 or later, see , "Configuring a Connector/ODBC 5.1 DSN on Windows".

Configuring a Connector/ODBC 3.51 DSN on Windows

To add or configure a Connector/ODBC 3.51 DSN on Windows, use either the command-line, or the ODBC Data Source Administrator GUI.

  1. Open the ODBC Data Source Administrator.
  2. To create a System DSN (which will be available to all users) , select the System DSN tab. To create a User DSN, which will be unique only to the current user, click the Add... button.
  3. You will need to select the ODBC driver for this DSN.MySQL ODBC Driver Selection Dialog

    Select MySQL ODBC 3.51 Driver, then click Finish.

  4. You now need to configure the specific fields for the DSN you are creating through the Add Data Source Name dialog.Add Data Source Name Dialog for Connector/ODBC 3.51.x

    In the Data Source Name box, enter the name of the data source to access. It can be any valid name that you choose.

  5. In the Description box, enter some text to help identify the connection.
  6. In the Server field, enter the name of the MariaDB server host to access. By default, it is localhost.
  7. In the User field, enter the user name to use for this connection.
  8. In the Password field, enter the corresponding password for this connection.
  9. The Database pop-up should automatically populate with the list of databases that the user has permissions to access.
  10. Click OK to save the DSN.

A completed DSN configuration may look like this:SampleMySQL ODBC DSN Configuration Dialog

You can verify the connection using the parameters you have entered by clicking the Test button. If the connection could be made successfully, you will be notified with a Success; connection was made! dialog.

If the connection failed, you can obtain more information on the test and why it may have failed by clicking the Diagnostics... button to show additional error messages.

You can configure a number of options for a specific DSN by using either the Connect Options or Advanced tabs in the DSN configuration dialog.Connector/ODBC Connect Options Dialog

The three options you can configure are:

The Advanced tab lets you configure Connector/ODBC connection parameters. Refer to , "Connector/ODBC Connection Parameters", for information about the meaning of these options.Connector/ODBC Connection Advanced Dialog

Configuring a Connector/ODBC 3.51 DSN on Windows, using the command-line

Use myodbc3i.exe when configuring Connector/ODBC 3.51 from the command-line.

Execute myodbc3i.exe without arguments to view a list of available options.

Configuring a Connector/ODBC 5.1 DSN on Windows

The DSN configuration when using Connector/ODBC 5.1.1 and later has a slightly different layout. Also, due to the native Unicode support within Connector/ODBC 5.1, you no longer need to specify the initial character set to be used with your connection.

To add or configure a Connector/ODBC 5.1 DSN on Windows, use either the command-line, or the ODBC Data Source Administrator GUI.

  1. Open the ODBC Data Source Administrator.
  2. To create a System DSN (which will be available to all users) , select the System DSN tab. To create a User DSN, which will be unique only to the current user, click the Add... button.
  3. You will need to select the ODBC driver for this DSN.MySQL ODBC Driver Selection Dialog

    Select MySQL ODBC 5.1 Driver, then click Finish.

  4. You now need to configure the specific fields for the DSN you are creating through the Connection Parameters dialog.Add Data Source Name Dialog for Connector/ODBC 5.1

    In the Data Source Name box, enter the name of the data source to access. It can be any valid name that you choose.

  5. In the Description box, enter some text to help identify the connection.
  6. In the Server field, enter the name of the MariaDB server host to access. By default, it is localhost.
  7. In the User field, enter the user name to use for this connection.
  8. In the Password field, enter the corresponding password for this connection.
  9. The Database pop-up should automatically populate with the list of databases that the user has permissions to access.
  10. To communicate over a different TCP/IP port than the default (3306), change the value of the Port.
  11. Click OK to save the DSN.

You can verify the connection using the parameters you have entered by clicking the Test button. If the connection could be made successfully, you will be notified with a Success; connection was made! dialog.

You can configure a number of options for a specific DSN by using the Details button.Connector/ODBC Connect Options Dialog

The Details button opens a tabbed display where you set additional options:

The Advanced tab lets you configure Connector/ODBC connection parameters. Refer to , "Connector/ODBC Connection Parameters", for information about the meaning of these options.

Configuring a Connector/ODBC 5.1 DSN on Windows, using the command-line

Use myodbc-installer.exe when configuring Connector/ODBC 5.1 or later from the command-line.

Execute myodbc-installer.exe without arguments to view a list of available options.

Troubleshooting ODBC Connection Problems

This section answers Connector/ODBC connection-related questions.

Configuring a Connector/ODBC DSN on Mac OS X

To configure a DSN on Mac OS X, you can either use the command-line utility (myodbc3i with connector/OCBC 3.51, or myodbc-installer with connector/ODBC 5.1), edit the odbc.ini file within the Library/ODBC directory of the user, or use the ODBC Administrator GUI. If you have Mac OS X 10.2 or earlier, refer to , "Configuring a Connector/ODBC DSN on Unix". Select whether to create a User DSN or a System DSN. When adding a System DSN, you might need to authenticate with the system. Click the padlock and enter a user and password with administrator privileges.

For correct operation of ODBC Administrator, ensure that the /Library/ODBC/odbc.ini file used to set up ODBC connectivity and DSNs are writable by the admin group. If this file is not writable by this group, then the ODBC Administrator may fail, or may appear to work but not generate the correct entry.Warning

There are known issues with the OS X ODBC Administrator and Connector/ODBC that may prevent you from creating a DSN using this method. In this case, use the command-line or edit the odbc.ini file directly. Note that existing DSNs or those that you create using the myodbc3i or myodbc-installer tool can still be checked and edited using ODBC Administrator.

To create a DSN using the myodbc3i utility, you need only specify the DSN type and the DSN connection string. For example: 

shell> myodbc3i -a -s -t'DSN=mydb;DRIVER=MySQL ODBC 3.51 Driver;SERVER=mysql;USER=username;PASSWORD=pass'

To use ODBC Administrator:

  1. Open the ODBC Administrator from the Utilities folder in the Applications folder.

    ODBC Administrator Main Panel Dialog
  2. On the User DSN or System DSN panel, click Add.
  3. Select the Connector/ODBC driver and click OK.
  4. You will be presented with the Data Source Name dialog. Enter The Data Source Name and an optional Description for the DSN.ODBC Administrator Add DSN Dialog
  5. Click Add to add a new keyword/value pair to the panel. Configure at least four pairs to specify the server, username, password and database connection parameters. See , "Connector/ODBC Connection Parameters".
  6. Click OK to add the DSN to the list of configured data source names.

A completed DSN configuration may look like this:ODBC Administrator Sample DSN Dialog

You can configure other ODBC options in your DSN by adding further keyword/value pairs and setting the corresponding values. See , "Connector/ODBC Connection Parameters".

Configuring a Connector/ODBC DSN on Unix

On Unix, you configure DSN entries directly in the odbc.ini file. Here is a typical odbc.ini file that configures myodbc3 as the DSN name for Connector/ODBC 3.51: 

;
; odbc.ini configuration for Connector/ODBC and Connector/ODBC 3.51 drivers
;
[ODBC Data Sources]
myodbc3 = MyODBC 3.51 Driver DSN
[myodbc3]
Driver = /usr/local/lib/libmyodbc3.so Description = Connector/ODBC 3.51 Driver DSN SERVER = localhost PORT =
USER = root Password =
Database = test OPTION = 3
SOCKET =
[Default]
Driver = /usr/local/lib/libmyodbc3.so Description = Connector/ODBC 3.51 Driver DSN SERVER = localhost PORT =
USER = root Password =
Database = test OPTION = 3
SOCKET =

Refer to the , "Connector/ODBC Connection Parameters", for the list of connection parameters that can be supplied.Note

If you are using unixODBC, you can use the following tools to set up the DSN:

In some cases when using unixODBC, you might get this error: 

Data source name not found and no default driver specified

If this happens, make sure the ODBCINI and ODBCSYSINI environment variables are pointing to the right odbc.ini file. For example, if your odbc.ini file is located in /usr/local/etc, set the environment variables like this: 

export ODBCINI=/usr/local/etc/odbc.ini export ODBCSYSINI=/usr/local/etc

Connecting Without a Predefined DSN

You can connect to the MariaDB server using SQLDriverConnect, by specifying the DRIVER name field. Here are the connection strings for Connector/ODBC using DSN-Less connections:

For Connector/ODBC 3.51:

ConnectionString = 'DRIVER={MySQL ODBC 3.51 Driver};\
 SERVER=localhost;\
 DATABASE=test;\
 USER=venu;\
 PASSWORD=venu;\
 OPTION=3;'

If your programming language converts backslash followed by whitespace to a space, it is preferable to specify the connection string as a single long string, or to use a concatenation of multiple strings that does not add spaces in between. For example: 

ConnectionString = 'DRIVER={MySQL ODBC 3.51 Driver};'
 'SERVER=localhost;'
 'DATABASE=test;'
 'USER=venu;'
 'PASSWORD=venu;'
 'OPTION=3;'

Note. Note that on Mac OS X you may need to specify the full path to the Connector/ODBC driver library.

Refer to the , "Connector/ODBC Connection Parameters", for the list of connection parameters that can be supplied.

ODBC Connection Pooling

Connection pooling enables the ODBC driver to re-use existing connections to a given database from a pool of connections, instead of opening a new connection each time the database is accessed. By enabling connection pooling you can improve the overall performance of your application by lowering the time taken to open a connection to a database in the connection pool.

For more information about connection pooling: http://support.microsoft.com/default.aspx?scid=kb;EN-US;q169470.

Getting an ODBC Trace File

Enabling ODBC Tracing on Windows
Enabling ODBC Tracing on Mac OS X
Enabling ODBC Tracing on Unix
Enabling a Connector/ODBC Log

If you encounter difficulties or problems with Connector/ODBC, start by making a log file from the ODBC Manager and Connector/ODBC. This is called tracing, and is enabled through the ODBC Manager. The procedure for this differs for Windows, Mac OS X and Unix.

Enabling ODBC Tracing on Windows

To enable the trace option on Windows:

  1. The Tracing tab of the ODBC Data Source Administrator dialog box lets you configure the way ODBC function calls are traced.

    ODBC Data Source Administrator Tracing Dialog
  2. When you activate tracing from the Tracing tab, the Driver Manager logs all ODBC function calls for all subsequently run applications.
  3. ODBC function calls from applications running before tracing is activated are not logged. ODBC function calls are recorded in a log file you specify.
  4. Tracing ceases only after you click Stop Tracing Now. Remember that while tracing is on, the log file continues to increase in size and that tracing affects the performance of all your ODBC applications.
Enabling ODBC Tracing on Mac OS X

To enable the trace option on Mac OS X 10.3 or later, use the Tracing tab within ODBC Administrator .

  1. Open the ODBC Administrator.
  2. Select the Tracing tab.ODBC Administrator Tracing Dialog
  3. Select the Enable Tracing check box.
  4. Enter the location to save the Tracing log. To append information to an existing log file, click the Choose... button.
Enabling ODBC Tracing on Unix

To enable the trace option on Mac OS X 10.2 (or earlier) or Unix you must add the trace option to the ODBC configuration:

  1. On Unix, you need to explicitly set the Trace option in the ODBC.INI file.

    Set the tracing ON or OFF by using TraceFile and Trace parameters in odbc.ini as shown below: 

    TraceFile = /tmp/odbc.trace Trace = 1

    TraceFile specifies the name and full path of the trace file and Trace is set to ON or OFF. You can also use 1 or YES for ON and 0 or NO for OFF. If you are using ODBCConfig from unixODBC, then follow the instructions for tracing unixODBC calls at HOWTO-ODBCConfig.

Enabling a Connector/ODBC Log

To generate a Connector/ODBC log, do the following:

  1. Within Windows, enable the Trace Connector/ODBC option flag in the Connector/ODBC connect/configure screen. The log is written to file C:\myodbc.log. If the trace option is not remembered when you are going back to the above screen, it means that you are not using the myodbcd.dll driver, see , "Troubleshooting ODBC Connection Problems".

    On Mac OS X, Unix, or if you are using DSN-Less connection, then you need to supply OPTION=4 in the connection string or set the corresponding keyword/value pair in the DSN.

  2. Start your application and try to get it to fail. Then check the Connector/ODBC trace file to find out what could be wrong.

If you need help determining what is wrong, see , "Connector/ODBC Community Support".

Connector/ODBC Examples

Basic Connector/ODBC Application Steps
Step-by-step Guide to Connecting to a MariaDB Database through Connector/ODBC
Connector/ODBC and Third-Party ODBC Tools
Using Connector/ODBC with Microsoft Access
Using Connector/ODBC with Microsoft Word or Excel
Using Connector/ODBC with Crystal Reports
Connector/ODBC Programming

Once you have configured a DSN to provide access to a database, how you access and use that connection is dependent on the application or programming language. As ODBC is a standardized interface, any application or language that supports ODBC can use the DSN and connect to the configured database.

Basic Connector/ODBC Application Steps

Interacting with a MariaDB server from an applications using the Connector/ODBC typically involves the following operations:

Most applications use some variation of these steps. The basic application steps are shown in the following diagram:Connector/ODBC Programming Flowchart

Step-by-step Guide to Connecting to a MariaDB Database through Connector/ODBC

A typical situation where you would install Connector/ODBC is to access a database on a Linux or Unix host from a Windows machine.

As an example of the process required to set up access between two machines, the steps below take you through the basic steps. These instructions assume that you connect to system ALPHA from system BETA with a user name and password of myuser and mypassword.

On system ALPHA (the MariaDB server) follow these steps:

  1. Start the MariaDB server.
  2. Use GRANT to set up an account with a user name of myuser that can connect from system BETA using a password of myuser to the database test: 
    GRANT ALL ON test.* to 'myuser'@'BETA' IDENTIFIED BY 'mypassword';

    For more information about MariaDB privileges, refer to , "MySQL User Account Management".

On system BETA (the Connector/ODBC client), follow these steps:

  1. Configure a Connector/ODBC DSN using parameters that match the server, database and authentication information that you have just configured on system ALPHA.

    Parameter Value Comment
    DSN remote_test A name to identify the connection.
    SERVER ALPHA The address of the remote server.
    DATABASE test The name of the default database.
    USER myuser The user name configured for access to this database.
    PASSWORD mypassword The password for myuser.
  2. Using an ODBC-capable application, such as Microsoft Office, connect to the MariaDB server using the DSN you have just created. If the connection fails, use tracing to examine the connection process. See , "Getting an ODBC Trace File", for more information.

Connector/ODBC and Third-Party ODBC Tools

Once you have configured your Connector/ODBC DSN, you can access your MariaDB database through any application that supports the ODBC interface, including programming languages and third-party applications. This section contains guides and help on using Connector/ODBC with various ODBC-compatible tools and applications, including Microsoft Word, Microsoft Excel and Adobe/Macromedia ColdFusion.

Connector/ODBC has been tested with the following applications.

Publisher Application Notes
Adobe ColdFusion Formerly Macromedia ColdFusion
Borland C++ Builder
Builder 4
Delphi
Business Objects Crystal Reports
Claris Filemaker Pro
Corel Paradox
Computer Associates Visual Objects Also known as CAVO
AllFusion ERwin Data Modeler
Gupta Team Developer Previously known as Centura Team Developer; Gupta SQL/Windows
Gensym G2-ODBC Bridge
Inline iHTML
Lotus Notes Versions 4.5 and 4.6
Microsoft Access
Excel
Visio Enterprise
Visual C++
Visual Basic
ODBC.NET Using C#, Visual Basic, C++
FoxPro
Visual Interdev
OpenOffice.org OpenOffice.org
Perl DBD::ODBC
Pervasive Software DataJunction
Sambar Technologies Sambar Server
SPSS SPSS
SoftVelocity Clarion
SQLExpress SQLExpress for Xbase++
Sun StarOffice
SunSystems Vision
Sybase PowerBuilder
PowerDesigner
theKompany.com Data Architect

If you know of any other applications that work with Connector/ODBC, please send mail to <myodbc@lists.mysql.com> about them.

Using Connector/ODBC with Microsoft Access

Exporting Access Data to MySQL
Importing MariaDB Data to Access
Using Microsoft Access as a Front-end to MySQL

You can use MariaDB database with Microsoft Access using Connector/ODBC. The MariaDB database can be used as an import source, an export source, or as a linked table for direct use within an Access application, so you can use Access as the front-end interface to a MariaDB database.

Exporting Access Data to MariaDB

To export a table of data from an Access database to MySQL, follow these instructions:

  1. When you open an Access database or an Access project, a Database window appears. It displays shortcuts for creating new database objects and opening existing objects.

    Access Database
  2. Click the name of the table or query to export, and then in the File menu, select Export.
  3. In the Export Object Type Object name To dialog box, in the Save As Type box, select ODBC Databases () as shown here:Selecting an ODBC Database
  4. In the Export dialog box, enter a name for the file (or use the suggested name), and then select OK.
  5. The Select Data Source dialog box is displayed; it lists the defined data sources for any ODBC drivers installed on your computer. Click either the File Data Source or Machine Data Source tab, and then double-click the Connector/ODBC or Connector/ODBC 3.51 data source to export to. To define a new data source for Connector/ODBC, please , "Configuring a Connector/ODBC DSN on Windows".
Note

Ensure that the information that you are exporting to the MariaDB table is valid for the corresponding MariaDB data types. Values that are outside of the supported range of the MariaDB data type but valid within Access may trigger an "overflow" error during the export.

Microsoft Access connects to the MariaDB Server through this data source and exports new tables and or data.

Importing MariaDB Data to Access

To import a table or tables from MariaDB to Access, follow these instructions:

  1. Open a database, or switch to the Database window for the open database.
  2. To import tables, on the File menu, point to Get External Data, and then click Import.
  3. In the Import dialog box, in the Files Of Type box, select ODBC Databases (). The Select Data Source dialog box lists the defined data sources The Select Data Source dialog box is displayed; it lists the defined data source names.
  4. If the ODBC data source that you selected requires you to log on, enter your login ID and password (additional information might also be required), and then click OK.
  5. Microsoft Access connects to the MariaDB server through ODBC data source and displays the list of tables that you can import.
  6. Click each table to import, and then click OK.
Using Microsoft Access as a Front-end to MariaDB

You can use Microsoft Access as a front end to a MariaDB database by linking tables within your Microsoft Access database to tables that exist within your MariaDB database. When a query is requested on a table within Access, ODBC is used to execute the queries on the MariaDB database instead.

To create a linked table:

  1. Open the Access database that you want to link to MariaDB.
  2. From the File, choose Get External Data->Link Tables.Linking Microsoft Access tables to MariaDB tables
  3. From the browser, choose ODBC Databases () from the Files of type pop-up.
  4. In the Select Data Source window, choose an existing DSN, either from a File Data Source or Machine Data Source.You can also create a new DSN using the New... button. For more information on creating a DSN see , "Configuring a Connector/ODBC DSN on Windows".Linking Microsoft Access tables to MariaDB tables, choosing a DSN
  5. In the Link Tables dialog, select one or more tables from the MariaDB database. A link will be created to each table that you select from this list.Linking Microsoft Access tables to MariaDB tables, table selection
  6. If Microsoft Access is unable to determine the unique record identifier for a table automatically then it may ask you to confirm the column, or combination of columns, to be used to uniquely identify each row from the source table. Select the columns to use and click OK.Linking Microsoft Access tables to MariaDB tables, choosing unique record identifier

Once the process has been completed, you can now build interfaces and queries to the linked tables just as you would for any Access database.

Use the following procedure to view or to refresh links when the structure or location of a linked table has changed. The Linked Table Manager lists the paths to all currently linked tables.

To view or refresh links:

  1. Open the database that contains links to MariaDB tables.
  2. On the Tools menu, point to Add-ins (Database Utilities in Access 2000 or newer), and then click Linked Table Manager.
  3. Select the check box for the tables whose links you want to refresh.
  4. Click OK to refresh the links.

Microsoft Access confirms a successful refresh or, if the table wasn't found, displays the Select New Location of <table name> dialog box in which you can specify its the table's new location. If several selected tables have moved to the new location that you specify, the Linked Table Manager searches that location for all selected tables, and updates all links in one step.

To change the path for a set of linked tables:

  1. Open the database that contains links to tables.
  2. On the Tools menu, point to Add-ins (Database Utilities in Access 2000 or newer), and then click Linked Table Manager.
  3. Select the Always Prompt For A New Location check box.
  4. Select the check box for the tables whose links you want to change, and then click OK.
  5. In the Select New Location of <table name> dialog box, specify the new location, click Open, and then click OK.

Using Connector/ODBC with Microsoft Word or Excel

You can use Microsoft Word and Microsoft Excel to access information from a MariaDB database using Connector/ODBC. Within Microsoft Word, this facility is most useful when importing data for mailmerge, or for tables and data to be included in reports. Within Microsoft Excel, you can execute queries on your MariaDB server and import the data directly into an Excel Worksheet, presenting the data as a series of rows and columns.

With both applications, data is accessed and imported into the application using Microsoft Query, which lets you execute a query though an ODBC source. You use Microsoft Query to build the SQL statement to be executed, selecting the tables, fields, selection criteria and sort order. For example, to insert information from a table in the World test database into an Excel spreadsheet, using the DSN samples shown in , "Connector/ODBC Configuration":

  1. Create a new Worksheet.
  2. From the Data menu, choose Import External Data, and then select New Database Query.
  3. Microsoft Query will start. First, you need to choose the data source, by selecting an existing Data Source Name.Microsoft Query, Choose Data Source
  4. Within the Query Wizard, you must choose the columns to import. The list of tables available to the user configured through the DSN is shown on the left, the columns that will be added to your query are shown on the right. The columns you choose are equivalent to those in the first section of a SELECT query. Click Next to continue.Microsoft Query, Choose Columns
  5. You can filter rows from the query (the equivalent of a WHERE clause) using the Filter Data dialog. Click Next to continue.Microsoft Query, Filter Data
  6. Select an (optional) sort order for the data. This is equivalent to using a ORDER BY clause in your SQL query. You can select up to three fields for sorting the information returned by the query. Click Next to continue.Microsoft Query, Sort Order
  7. Select the destination for your query. You can select to return the data Microsoft Excel, where you can choose a worksheet and cell where the data will be inserted; you can continue to view the query and results within Microsoft Query, where you can edit the SQL query and further filter and sort the information returned; or you can create an OLAP Cube from the query, which can then be used directly within Microsoft Excel. Click Finish.Microsoft Query, Selecting a destination

The same process can be used to import data into a Word document, where the data will be inserted as a table. This can be used for mail merge purposes (where the field data is read from a Word table), or where you want to include data and reports within a report or other document.

Using Connector/ODBC with Crystal Reports

Crystal Reports can use an ODBC DSN to connect to a database from which you to extract data and information for reporting purposes.Note

There is a known issue with certain versions of Crystal Reports where the application is unable to open and browse tables and fields through an ODBC connection. Before using Crystal Reports with MySQL, please ensure that you have update to the latest version, including any outstanding service packs and hotfixes. For more information on this issue, see the Business) Objects Knowledgebase for more information.

For example, to create a simple crosstab report within Crystal Reports XI, follow these steps:

  1. Create a DSN using the Data Sources (ODBC) tool. You can either specify a complete database, including user name and password, or you can build a basic DSN and use Crystal Reports to set the user name and password.

    For the purposes of this example, a DSN that provides a connection to an instance of the MariaDB Sakila sample database has been created.

  2. Open Crystal Reports and create a new project, or an open an existing reporting project into which you want to insert data from your MariaDB data source.
  3. Start the Cross-Tab Report Wizard, either by clicking the option on the Start Page. Expand the Create New Connection folder, then expand the ODBC (RDO) folder to obtain a list of ODBC data sources.

    You will be asked to select a data source.Selecting an Data Source in Crystal Reports

  4. When you first expand the ODBC (RDO) folder you will be presented the Data Source Selection screen. From here you can select either a pre-configured DSN, open a file-based DSN or enter and manual connection string. For this example, the Sakila DSN will be used.

    If the DSN contains a user name/password combination, or you want to use different authentication credentials, click Next to enter the user name and password that you want to use. Otherwise, click Finish to continue the data source selection wizard.Selecting an ODBC Data Source in Crystal Reports

  5. You will be returned the Cross-Tab Report Creation Wizard. You now need to select the database and tables that you want to include in your report. For our example, we will expand the selected Sakila database. Click the city table and use the > button to add the table to the report. Then repeat the action with the country table. Alternatively you can select multiple tables and add them to the report.

    Finally, you can select the parent Sakila resource and add of the tables to the report.

    Once you have selected the tables you want to include, click Next to continue.Selecting an tables in Crystal Reports

  6. Crystal Reports will now read the table definitions and automatically identify the links between the tables. The identification of links between tables enables Crystal Reports to automatically lookup and summarize information based on all the tables in the database according to your query. If Crystal Reports is unable to perform the linking itself, you can manually create the links between fields in the tables you have selected.

    Click Next to continue the process.Table links/structure in Crystal Reports

  7. You can now select the columns and rows that to include within the Cross-Tab report. Drag and drop or use the > buttons to add fields to each area of the report. In the example shown, we will report on cities, organized by country, incorporating a count of the number of cities within each country. If you want to browse the data, select a field and click the Browse Data... button.

    Click Next to create a graph of the results. Since we are not creating a graph from this data, click Finish to generate the report.Cross-tab definition in Crystal Reports

  8. The finished report will be shown, a sample of the output from the Sakila sample database is shown below.Cross-tab final report in Crystal Reports

Once the ODBC connection has been opened within Crystal Reports, you can browse and add any fields within the available tables into your reports.

Connector/ODBC Programming

Using Connector/ODBC with Visual Basic Using ADO, DAO and RDO
Using Connector/ODBC with .NET

With a suitable ODBC Manager and the Connector/ODBC driver installed, any programming language or environment that can support ODBC can connect to a MariaDB database through Connector/ODBC.

This includes, but is not limited to, Microsoft support languages (including Visual Basic, C# and interfaces such as ODBC.NET), Perl (through the DBI module, and the DBD::ODBC driver).

Using Connector/ODBC with Visual Basic Using ADO, DAO and RDO
ADO: rs.addNew, rs.delete, and rs.update
DAO: rs.addNew, rs.update, and Scrolling
RDO: rs.addNew and rs.update

This section contains simple examples of the use of MariaDB ODBC 3.51 Driver with ADO, DAO and RDO.

ADO: rs.addNew, rs.delete, and rs.update

The following ADO (ActiveX Data Objects) example creates a table my_ado and demonstrates the use of rs.addNew, rs.delete, and rs.update. 

Private Sub myodbc_ado_Click()
Dim conn As ADODB.Connection Dim rs As ADODB.Recordset Dim fld As ADODB.Field Dim sql As String
'connect to MariaDB server using MariaDB ODBC 3.51 Driver Set conn = New ADODB.Connection conn.ConnectionString = 'DRIVER={MySQL ODBC 3.51 Driver};'_
& 'SERVER=localhost;'_
& ' DATABASE=test;'_
& 'UID=venu;PWD=venu; OPTION=3'
conn.Open
'create table conn.Execute 'DROP TABLE IF EXISTS my_ado'
conn.Execute 'CREATE TABLE my_ado(id int not null primary key, name varchar(20),' _
& 'txt text, dt date, tm time, ts timestamp)'
'direct insert conn.Execute 'INSERT INTO my_ado(id,name,txt) values(1,100,'venu')'
conn.Execute 'INSERT INTO my_ado(id,name,txt) values(2,200,'MySQL')'
conn.Execute 'INSERT INTO my_ado(id,name,txt) values(3,300,'Delete')'
Set rs = New ADODB.Recordset rs.CursorLocation = adUseServer
'fetch the initial table ..
rs.Open 'SELECT * FROM my_ado', conn Debug.Print rs.RecordCount rs.MoveFirst Debug.Print String(50, '-') & 'Initial my_ado Result Set ' & String(50, '-')
For Each fld In rs.Fields Debug.Print fld.Name,
Next Debug.Print Do Until rs.EOF For Each fld In rs.Fields Debug.Print fld.Value,
Next rs.MoveNext Debug.Print Loop rs.Close
'rs insert rs.Open 'select * from my_ado', conn, adOpenDynamic, adLockOptimistic rs.AddNew rs!Name = 'Monty'
rs!txt = 'Insert row'
rs.Update rs.Close
'rs update rs.Open 'SELECT * FROM my_ado'
rs!Name = 'update'
rs!txt = 'updated-row'
rs.Update rs.Close
'rs update second time..
rs.Open 'SELECT * FROM my_ado'
rs!Name = 'update'
rs!txt = 'updated-second-time'
rs.Update rs.Close
'rs delete rs.Open 'SELECT * FROM my_ado'
rs.MoveNext rs.MoveNext rs.Delete rs.Close
'fetch the updated table ..
rs.Open 'SELECT * FROM my_ado', conn Debug.Print rs.RecordCount rs.MoveFirst Debug.Print String(50, '-') & 'Updated my_ado Result Set ' & String(50, '-')
For Each fld In rs.Fields Debug.Print fld.Name,
Next Debug.Print Do Until rs.EOF For Each fld In rs.Fields Debug.Print fld.Value,
Next rs.MoveNext Debug.Print Loop rs.Close conn.Close End Sub
DAO: rs.addNew, rs.update, and Scrolling

The following DAO (Data Access Objects) example creates a table my_dao and demonstrates the use of rs.addNew, rs.update, and result set scrolling. 

Private Sub myodbc_dao_Click()
Dim ws As Workspace Dim conn As Connection Dim queryDef As queryDef Dim str As String
'connect to MariaDB using MariaDB ODBC 3.51 Driver Set ws = DBEngine.CreateWorkspace('', 'venu', 'venu', dbUseODBC)
str = 'odbc;DRIVER={MySQL ODBC 3.51 Driver};'_
& 'SERVER=localhost;'_
& ' DATABASE=test;'_
& 'UID=venu;PWD=venu; OPTION=3'
Set conn = ws.OpenConnection('test', dbDriverNoPrompt, False, str)
'Create table my_dao Set queryDef = conn.CreateQueryDef('', 'drop table if exists my_dao')
queryDef.Execute Set queryDef = conn.CreateQueryDef('', 'create table my_dao(Id INT AUTO_INCREMENT PRIMARY KEY, ' _
& 'Ts TIMESTAMP(14) NOT NULL, Name varchar(20), Id2 INT)')
queryDef.Execute
'Insert new records using rs.addNew Set rs = conn.OpenRecordset('my_dao')
Dim i As Integer For i = 10 To 15
rs.AddNew rs!Name = 'insert record' & i rs!Id2 = i rs.Update Next i rs.Close
'rs update..
Set rs = conn.OpenRecordset('my_dao')
rs.Edit rs!Name = 'updated-string'
rs.Update rs.Close
'fetch the table back...
Set rs = conn.OpenRecordset('my_dao', dbOpenDynamic)
str = 'Results:'
rs.MoveFirst While Not rs.EOF str = ' ' & rs!Id & ' , ' & rs!Name & ', ' & rs!Ts & ', ' & rs!Id2
Debug.Print 'DATA:' & str rs.MoveNext Wend
'rs Scrolling rs.MoveFirst str = ' FIRST ROW: ' & rs!Id & ' , ' & rs!Name & ', ' & rs!Ts & ', ' & rs!Id2
Debug.Print str rs.MoveLast str = ' LAST ROW: ' & rs!Id & ' , ' & rs!Name & ', ' & rs!Ts & ', ' & rs!Id2
Debug.Print str rs.MovePrevious str = ' LAST-1 ROW: ' & rs!Id & ' , ' & rs!Name & ', ' & rs!Ts & ', ' & rs!Id2
Debug.Print str
'free all resources rs.Close queryDef.Close conn.Close ws.Close End Sub
RDO: rs.addNew and rs.update

The following RDO (Remote Data Objects) example creates a table my_rdo and demonstrates the use of rs.addNew and rs.update. 

Dim rs As rdoResultset Dim cn As New rdoConnection Dim cl As rdoColumn Dim SQL As String
'cn.Connect = 'DSN=test;'
cn.Connect = 'DRIVER={MySQL ODBC 3.51 Driver};'_
& 'SERVER=localhost;'_
& ' DATABASE=test;'_
& 'UID=venu;PWD=venu; OPTION=3'
cn.CursorDriver = rdUseOdbc cn.EstablishConnection rdDriverPrompt
'drop table my_rdo SQL = 'drop table if exists my_rdo'
cn.Execute SQL, rdExecDirect
'create table my_rdo SQL = 'create table my_rdo(id int, name varchar(20))'
cn.Execute SQL, rdExecDirect
'insert - direct SQL = 'insert into my_rdo values (100,'venu')'
cn.Execute SQL, rdExecDirect SQL = 'insert into my_rdo values (200,'MySQL')'
cn.Execute SQL, rdExecDirect
'rs insert SQL = 'select * from my_rdo'
Set rs = cn.OpenResultset(SQL, rdOpenStatic, rdConcurRowVer, rdExecDirect)
rs.AddNew rs!id = 300
rs!Name = 'Insert1'
rs.Update rs.Close
'rs insert SQL = 'select * from my_rdo'
Set rs = cn.OpenResultset(SQL, rdOpenStatic, rdConcurRowVer, rdExecDirect)
rs.AddNew rs!id = 400
rs!Name = 'Insert 2'
rs.Update rs.Close
'rs update SQL = 'select * from my_rdo'
Set rs = cn.OpenResultset(SQL, rdOpenStatic, rdConcurRowVer, rdExecDirect)
rs.Edit rs!id = 999
rs!Name = 'updated'
rs.Update rs.Close
'fetch back...
SQL = 'select * from my_rdo'
Set rs = cn.OpenResultset(SQL, rdOpenStatic, rdConcurRowVer, rdExecDirect)
Do Until rs.EOF For Each cl In rs.rdoColumns Debug.Print cl.Value,
Next rs.MoveNext Debug.Print Loop Debug.Print 'Row count="; rs.RowCount
"close rs.Close cn.Close End Sub
Using Connector/ODBC with .NET
Using Connector/ODBC with ODBC.NET and C# (C sharp)
Using Connector/ODBC with ODBC.NET and Visual Basic

This section contains simple examples that demonstrate the use of Connector/ODBC drivers with ODBC.NET.

Using Connector/ODBC with ODBC.NET and C# (C sharp)

The following sample creates a table my_odbc_net and demonstrates its use in C#. 

/**
 * @sample : mycon.cs
 * @purpose : Demo sample for ODBC.NET using Connector/ODBC
 * @author : Venu, <myodbc@lists.mysql.com>
 *
 * (C) Copyright MariaDB Foundation, 1995-2006
 *
 **/
/* build command
 *
 * csc /t:exe
 * /out:mycon.exe mycon.cs
 * /r:Microsoft.Data.Odbc.dll
 */
using Console = System.Console;
using Microsoft.Data.Odbc;
namespace myodbc3
{
 class mycon
 {
 static void Main(string[] args)
 {
 try
 {
 //Connection string for Connector/ODBC 3.51
 string MyConString = 'DRIVER={MySQL ODBC 3.51 Driver};' +
 'SERVER=localhost;' +
 'DATABASE=test;' +
 'UID=venu;' +
 'PASSWORD=venu;' +
 'OPTION=3';
 //Connect to MariaDB using Connector/ODBC
 OdbcConnection MyConnection = new OdbcConnection(MyConString);
 MyConnection.Open();
 Console.WriteLine('\n !!! success, connected successfully !!!\n');
 //Display connection information
 Console.WriteLine('Connection Information:');
 Console.WriteLine('\tConnection String:' +
 MyConnection.ConnectionString);
 Console.WriteLine('\tConnection Timeout:' +
 MyConnection.ConnectionTimeout);
 Console.WriteLine('\tDatabase:' +
 MyConnection.Database);
 Console.WriteLine('\tDataSource:' +
 MyConnection.DataSource);
 Console.WriteLine('\tDriver:' +
 MyConnection.Driver);
 Console.WriteLine('\tServerVersion:' +
 MyConnection.ServerVersion);
 //Create a sample table
 OdbcCommand MyCommand =
 new OdbcCommand('DROP TABLE IF EXISTS my_odbc_net',
 MyConnection);
 MyCommand.ExecuteNonQuery();
 MyCommand.CommandText =
 'CREATE TABLE my_odbc_net(id int, name varchar(20), idb bigint)';
 MyCommand.ExecuteNonQuery();
 //Insert
 MyCommand.CommandText =
 'INSERT INTO my_odbc_net VALUES(10,'venu', 300)';
 Console.WriteLine('INSERT, Total rows affected:' +
 MyCommand.ExecuteNonQuery());;
 //Insert
 MyCommand.CommandText =
 'INSERT INTO my_odbc_net VALUES(20,'mysql',400)';
 Console.WriteLine('INSERT, Total rows affected:' +
 MyCommand.ExecuteNonQuery());
 //Insert
 MyCommand.CommandText =
 'INSERT INTO my_odbc_net VALUES(20,'mysql',500)';
 Console.WriteLine('INSERT, Total rows affected:' +
 MyCommand.ExecuteNonQuery());
 //Update
 MyCommand.CommandText =
 'UPDATE my_odbc_net SET id=999 WHERE id=20';
 Console.WriteLine('Update, Total rows affected:' +
 MyCommand.ExecuteNonQuery());
 //COUNT(*)
 MyCommand.CommandText =
 'SELECT COUNT(*) as TRows FROM my_odbc_net';
 Console.WriteLine('Total Rows:' +
 MyCommand.ExecuteScalar());
 //Fetch
 MyCommand.CommandText = 'SELECT * FROM my_odbc_net';
 OdbcDataReader MyDataReader;
 MyDataReader = MyCommand.ExecuteReader();
 while (MyDataReader.Read())
 {
 if(string.Compare(MyConnection.Driver,'myodbc3.dll') == 0) {
 //Supported only by Connector/ODBC 3.51
 Console.WriteLine('Data:' + MyDataReader.GetInt32(0) + ' ' +
 MyDataReader.GetString(1) + ' ' +
 MyDataReader.GetInt64(2));
 }
 else {
 //BIGINTs not supported by Connector/ODBC
 Console.WriteLine('Data:' + MyDataReader.GetInt32(0) + ' ' +
 MyDataReader.GetString(1) + ' ' +
 MyDataReader.GetInt32(2));
 }
 }
 //Close all resources
 MyDataReader.Close();
 MyConnection.Close();
 }
 catch (OdbcException MyOdbcException) //Catch any ODBC exception ..
 {
 for (int i=0; i < MyOdbcException.Errors.Count; i++)
 {
 Console.Write('ERROR #' + i + '\n' +
 'Message: ' +
 MyOdbcException.Errors[i].Message + '\n' +
 'Native: ' +
 MyOdbcException.Errors[i].NativeError.ToString() + '\n' +
 'Source: ' +
 MyOdbcException.Errors[i].Source + '\n' +
 'SQL: ' +
 MyOdbcException.Errors[i].SQLState + '\n');
 }
 }
 }
 }
}
Using Connector/ODBC with ODBC.NET and Visual Basic

The following sample creates a table my_vb_net and demonstrates the use in VB. 

' @sample : myvb.vb
' @purpose : Demo sample for ODBC.NET using Connector/ODBC
' @author : Venu, <myodbc@lists.mysql.com>
'
' (C) Copyright MariaDB Foundation, 1995-2006
'
'
'
' build command
'
' vbc /target:exe
' /out:myvb.exe
' /r:Microsoft.Data.Odbc.dll
' /r:System.dll
' /r:System.Data.dll
'
Imports Microsoft.Data.Odbc Imports System Module myvb
 Sub Main()
 Try
 'Connector/ODBC 3.51 connection string
 Dim MyConString As String = 'DRIVER={MySQL ODBC 3.51 Driver};' & _
 'SERVER=localhost;' & _
 'DATABASE=test;' & _
 'UID=venu;' & _
 'PASSWORD=venu;' & _
 'OPTION=3;'
 'Connection
 Dim MyConnection As New OdbcConnection(MyConString)
 MyConnection.Open()
 Console.WriteLine('Connection State::' & MyConnection.State.ToString)
 'Drop
 Console.WriteLine('Dropping table')
 Dim MyCommand As New OdbcCommand()
 MyCommand.Connection = MyConnection
 MyCommand.CommandText = 'DROP TABLE IF EXISTS my_vb_net'
 MyCommand.ExecuteNonQuery()
 'Create
 Console.WriteLine('Creating....')
 MyCommand.CommandText = 'CREATE TABLE my_vb_net(id int, name varchar(30))'
 MyCommand.ExecuteNonQuery()
 'Insert
 MyCommand.CommandText = 'INSERT INTO my_vb_net VALUES(10,'venu')'
 Console.WriteLine('INSERT, Total rows affected:' & _
 MyCommand.ExecuteNonQuery())
 'Insert
 MyCommand.CommandText = 'INSERT INTO my_vb_net VALUES(20,'mysql')'
 Console.WriteLine('INSERT, Total rows affected:' & _
 MyCommand.ExecuteNonQuery())
 'Insert
 MyCommand.CommandText = 'INSERT INTO my_vb_net VALUES(20,'mysql')'
 Console.WriteLine('INSERT, Total rows affected:' & _
 MyCommand.ExecuteNonQuery())
 'Insert
 MyCommand.CommandText = 'INSERT INTO my_vb_net(id) VALUES(30)'
 Console.WriteLine('INSERT, Total rows affected:' & _
 MyCommand.ExecuteNonQuery())
 'Update
 MyCommand.CommandText = 'UPDATE my_vb_net SET id=999 WHERE id=20'
 Console.WriteLine('Update, Total rows affected:' & _
 MyCommand.ExecuteNonQuery())
 'COUNT(*)
 MyCommand.CommandText = 'SELECT COUNT(*) as TRows FROM my_vb_net'
 Console.WriteLine('Total Rows:' & MyCommand.ExecuteScalar())
 'Select
 Console.WriteLine('Select * FROM my_vb_net')
 MyCommand.CommandText = 'SELECT * FROM my_vb_net'
 Dim MyDataReader As OdbcDataReader
 MyDataReader = MyCommand.ExecuteReader
 While MyDataReader.Read
 If MyDataReader('name') Is DBNull.Value Then
 Console.WriteLine('id = ' & _
 CStr(MyDataReader('id')) & ' name = ' & _
 'NULL')
 Else
 Console.WriteLine('id = ' & _
 CStr(MyDataReader('id')) & ' name = ' & _
 CStr(MyDataReader('name')))
 End If
 End While
 'Catch ODBC Exception
 Catch MyOdbcException As OdbcException
 Dim i As Integer
 Console.WriteLine(MyOdbcException.ToString)
 'Catch program exception
 Catch MyException As Exception
 Console.WriteLine(MyException.ToString)
 End Try
 End Sub

Connector/ODBC Reference

Connector/ODBC API Reference
Connector/ODBC Data Types
Connector/ODBC Error Codes

This section provides reference material for the Connector/ODBC API, showing supported functions and methods, supported MariaDB column types and the corresponding native type in Connector/ODBC, and the error codes returned by Connector/ODBC when a fault occurs.

Connector/ODBC API Reference

This section summarizes ODBC routines, categorized by functionality.

For the complete ODBC API reference, please refer to the ODBC Programmer's Reference at http://msdn.microsoft.com/en-us/library/ms714177.aspx.

An application can call SQLGetInfo function to obtain conformance information about Connector/ODBC. To obtain information about support for a specific function in the driver, an application can call SQLGetFunctions.Note

For backward compatibility, the Connector/ODBC 3.51 driver supports all deprecated functions.

The following tables list Connector/ODBC API calls grouped by task:

Connecting to a data source

Function name C/ODBC 3.51 Standard Purpose
SQLAllocHandle Yes ISO 92 Obtains an environment, connection, statement, or descriptor handle.
SQLConnect Yes ISO 92 Connects to a specific driver by data source name, user ID, and password.
SQLDriverConnect Yes ODBC Connects to a specific driver by connection string or requests that the Driver Manager and driver display connection dialog boxes for the user.
SQLAllocEnv Yes Deprecated Obtains an environment handle allocated from driver.
SQLAllocConnect Yes Deprecated Obtains a connection handle

Obtaining information about a driver and data source

Function name C/ODBC 3.51 Standard Purpose
SQLDataSources No ISO 92 Returns the list of available data sources, handled by the Driver Manager
SQLDrivers No ODBC Returns the list of installed drivers and their attributes, handles by Driver Manager
SQLGetInfo Yes ISO 92 Returns information about a specific driver and data source.
SQLGetFunctions Yes ISO 92 Returns supported driver functions.
SQLGetTypeInfo Yes ISO 92 Returns information about supported data types.

Setting and retrieving driver attributes

Function name C/ODBC 3.51 Standard Purpose
SQLSetConnectAttr Yes ISO 92 Sets a connection attribute.
SQLGetConnectAttr Yes ISO 92 Returns the value of a connection attribute.
SQLSetConnectOption Yes Deprecated Sets a connection option
SQLGetConnectOption Yes Deprecated Returns the value of a connection option
SQLSetEnvAttr Yes ISO 92 Sets an environment attribute.
SQLGetEnvAttr Yes ISO 92 Returns the value of an environment attribute.
SQLSetStmtAttr Yes ISO 92 Sets a statement attribute.
SQLGetStmtAttr Yes ISO 92 Returns the value of a statement attribute.
SQLSetStmtOption Yes Deprecated Sets a statement option
SQLGetStmtOption Yes Deprecated Returns the value of a statement option

Preparing SQL requests

Function name C/ODBC 3.51 Standard Purpose
SQLAllocStmt Yes Deprecated Allocates a statement handle
SQLPrepare Yes ISO 92 Prepares an SQL statement for later execution.
SQLBindParameter Yes ODBC Assigns storage for a parameter in an SQL statement.
SQLGetCursorName Yes ISO 92 Returns the cursor name associated with a statement handle.
SQLSetCursorName Yes ISO 92 Specifies a cursor name.
SQLSetScrollOptions Yes ODBC Sets options that control cursor behavior.

Submitting requests

Function name C/ODBC 3.51 Standard Purpose
SQLExecute Yes ISO 92 Executes a prepared statement.
SQLExecDirect Yes ISO 92 Executes a statement
SQLNativeSql Yes ODBC Returns the text of an SQL statement as translated by the driver.
SQLDescribeParam Yes ODBC Returns the description for a specific parameter in a statement.
SQLNumParams Yes ISO 92 Returns the number of parameters in a statement.
SQLParamData Yes ISO 92 Used in conjunction with SQLPutData to supply parameter data at execution time. (Useful for long data values.)
SQLPutData Yes ISO 92 Sends part or all of a data value for a parameter. (Useful for long data values.)

Retrieving results and information about results

Function name C/ODBC 3.51 Standard Purpose
SQLRowCount Yes ISO 92 Returns the number of rows affected by an insert, update, or delete request.
SQLNumResultCols Yes ISO 92 Returns the number of columns in the result set.
SQLDescribeCol Yes ISO 92 Describes a column in the result set.
SQLColAttribute Yes ISO 92 Describes attributes of a column in the result set.
SQLColAttributes Yes Deprecated Describes attributes of a column in the result set.
SQLFetch Yes ISO 92 Returns multiple result rows.
SQLFetchScroll Yes ISO 92 Returns scrollable result rows.
SQLExtendedFetch Yes Deprecated Returns scrollable result rows.
SQLSetPos Yes ODBC Positions a cursor within a fetched block of data and enables an application to refresh data in the rowset or to update or delete data in the result set.
SQLBulkOperations Yes ODBC Performs bulk insertions and bulk bookmark operations, including update, delete, and fetch by bookmark.

Retrieving error or diagnostic information

Function name C/ODBC 3.51 Standard Purpose
SQLError Yes Deprecated Returns additional error or status information
SQLGetDiagField Yes ISO 92 Returns additional diagnostic information (a single field of the diagnostic data structure).
SQLGetDiagRec Yes ISO 92 Returns additional diagnostic information (multiple fields of the diagnostic data structure).

Obtaining information about the data source's system tables (catalog functions) item

Function name C/ODBC 3.51 Standard Purpose
SQLColumnPrivileges Yes ODBC Returns a list of columns and associated privileges for one or more tables.
SQLColumns Yes X/Open Returns the list of column names in specified tables.
SQLForeignKeys Yes ODBC Returns a list of column names that make up foreign keys, if they exist for a specified table.
SQLPrimaryKeys Yes ODBC Returns the list of column names that make up the primary key for a table.
SQLSpecialColumns Yes X/Open Returns information about the optimal set of columns that uniquely identifies a row in a specified table, or the columns that are automatically updated when any value in the row is updated by a transaction.
SQLStatistics Yes ISO 92 Returns statistics about a single table and the list of indexes associated with the table.
SQLTablePrivileges Yes ODBC Returns a list of tables and the privileges associated with each table.
SQLTables Yes X/Open Returns the list of table names stored in a specific data source.

Performing transactions

Function name C/ODBC 3.51 Standard Purpose
SQLTransact Yes Deprecated Commits or rolls back a transaction
SQLEndTran Yes ISO 92 Commits or rolls back a transaction.

Terminating a statement

Function name C/ODBC 3.51 Standard Purpose
SQLFreeStmt Yes ISO 92 Ends statement processing, discards pending results, and, optionally, frees all resources associated with the statement handle.
SQLCloseCursor Yes ISO 92 Closes a cursor that has been opened on a statement handle.
SQLCancel Yes ISO 92 Cancels an SQL statement.

Terminating a connection

Function name C/ODBC 3.51 Standard Purpose
SQLDisconnect Yes ISO 92 Closes the connection.
SQLFreeHandle Yes ISO 92 Releases an environment, connection, statement, or descriptor handle.
SQLFreeConnect Yes Deprecated Releases connection handle
SQLFreeEnv Yes Deprecated Releases an environment handle

Connector/ODBC Data Types

The following table illustrates how driver maps the server data types to default SQL and C data types.

Native Value SQL Type C Type
bigint unsigned SQL_BIGINT SQL_C_UBIGINT
bigint SQL_BIGINT SQL_C_SBIGINT
bit SQL_BIT SQL_C_BIT
bit SQL_CHAR SQL_C_CHAR
blob SQL_LONGVARBINARY SQL_C_BINARY
bool SQL_CHAR SQL_C_CHAR
char SQL_CHAR SQL_C_CHAR
date SQL_DATE SQL_C_DATE
datetime SQL_TIMESTAMP SQL_C_TIMESTAMP
decimal SQL_DECIMAL SQL_C_CHAR
double precision SQL_DOUBLE SQL_C_DOUBLE
double SQL_FLOAT SQL_C_DOUBLE
enum SQL_VARCHAR SQL_C_CHAR
float SQL_REAL SQL_C_FLOAT
int unsigned SQL_INTEGER SQL_C_ULONG
int SQL_INTEGER SQL_C_SLONG
integer unsigned SQL_INTEGER SQL_C_ULONG
integer SQL_INTEGER SQL_C_SLONG
long varbinary SQL_LONGVARBINARY SQL_C_BINARY
long varchar SQL_LONGVARCHAR SQL_C_CHAR
longblob SQL_LONGVARBINARY SQL_C_BINARY
longtext SQL_LONGVARCHAR SQL_C_CHAR
mediumblob SQL_LONGVARBINARY SQL_C_BINARY
mediumint unsigned SQL_INTEGER SQL_C_ULONG
mediumint SQL_INTEGER SQL_C_SLONG
mediumtext SQL_LONGVARCHAR SQL_C_CHAR
numeric SQL_NUMERIC SQL_C_CHAR
real SQL_FLOAT SQL_C_DOUBLE
set SQL_VARCHAR SQL_C_CHAR
smallint unsigned SQL_SMALLINT SQL_C_USHORT
smallint SQL_SMALLINT SQL_C_SSHORT
text SQL_LONGVARCHAR SQL_C_CHAR
time SQL_TIME SQL_C_TIME
timestamp SQL_TIMESTAMP SQL_C_TIMESTAMP
tinyblob SQL_LONGVARBINARY SQL_C_BINARY
tinyint unsigned SQL_TINYINT SQL_C_UTINYINT
tinyint SQL_TINYINT SQL_C_STINYINT
tinytext SQL_LONGVARCHAR SQL_C_CHAR
varchar SQL_VARCHAR SQL_C_CHAR
year SQL_SMALLINT SQL_C_SHORT

Connector/ODBC Error Codes

The following tables lists the error codes returned by the driver apart from the server errors.

Native Code SQLSTATE 2 SQLSTATE 3 Error Message
500 01000 01000 General warning
501 01004 01004 String data, right truncated
502 01S02 01S02 Option value changed
503 01S03 01S03 No rows updated/deleted
504 01S04 01S04 More than one row updated/deleted
505 01S06 01S06 Attempt to fetch before the result set returned the first row set
506 07001 07002 SQLBindParameter not used for all parameters
507 07005 07005 Prepared statement not a cursor-specification
508 07009 07009 Invalid descriptor index
509 08002 08002 Connection name in use
510 08003 08003 Connection does not exist
511 24000 24000 Invalid cursor state
512 25000 25000 Invalid transaction state
513 25S01 25S01 Transaction state unknown
514 34000 34000 Invalid cursor name
515 S1000 HY000 General driver defined error
516 S1001 HY001 Memory allocation error
517 S1002 HY002 Invalid column number
518 S1003 HY003 Invalid application buffer type
519 S1004 HY004 Invalid SQL data type
520 S1009 HY009 Invalid use of null pointer
521 S1010 HY010 Function sequence error
522 S1011 HY011 Attribute can not be set now
523 S1012 HY012 Invalid transaction operation code
524 S1013 HY013 Memory management error
525 S1015 HY015 No cursor name available
526 S1024 HY024 Invalid attribute value
527 S1090 HY090 Invalid string or buffer length
528 S1091 HY091 Invalid descriptor field identifier
529 S1092 HY092 Invalid attribute/option identifier
530 S1093 HY093 Invalid parameter number
531 S1095 HY095 Function type out of range
532 S1106 HY106 Fetch type out of range
533 S1117 HY117 Row value out of range
534 S1109 HY109 Invalid cursor position
535 S1C00 HYC00 Optional feature not implemented
0 21S01 21S01 Column count does not match value count
0 23000 23000 Integrity constraint violation
0 42000 42000 Syntax error or access violation
0 42S02 42S02 Base table or view not found
0 42S12 42S12 Index not found
0 42S21 42S21 Column already exists
0 42S22 42S22 Column not found
0 08S01 08S01 Communication link failure

Connector/ODBC Notes and Tips

Connector/ODBC General Functionality
Connector/ODBC Application-Specific Tips
Connector/ODBC Errors and Resolutions (FAQ)

Here are some common notes and tips for using Connector/ODBC within different environments, applications and tools. The notes provided here are based on the experiences of Connector/ODBC developers and users.

Connector/ODBC General Functionality

Obtaining Auto-Increment Values
Dynamic Cursor Support
Connector/ODBC Performance
Setting ODBC Query Timeout in Windows

This section provides help with common queries and areas of functionality in MariaDB and how to use them with Connector/ODBC.

Obtaining Auto-Increment Values

Obtaining the value of column that uses AUTO_INCREMENT after an INSERT statement can be achieved in a number of different ways. To obtain the value immediately after an INSERT, use a SELECT query with the LAST_INSERT_ID() function.

For example, using Connector/ODBC you would execute two separate statements, the INSERT statement and the SELECT query to obtain the auto-increment value. 

INSERT INTO tbl (auto,text) VALUES(NULL,'text');
SELECT LAST_INSERT_ID();

If you do not require the value within your application, but do require the value as part of another INSERT, the entire process can be handled by executing the following statements: 

INSERT INTO tbl (auto,text) VALUES(NULL,'text');
INSERT INTO tbl2 (id,text) VALUES(LAST_INSERT_ID(),'text');

Certain ODBC applications (including Delphi and Access) may have trouble obtaining the auto-increment value using the previous examples. In this case, try the following statement as an alternative: 

SELECT * FROM tbl WHERE auto IS NULL;

This alternative method requires that sql-auto-is-null variable is not set to 0. See , "Server System Variables".

See also , "How to Get the Unique ID for the Last Inserted Row".

Dynamic Cursor Support

Support for the dynamic cursor is provided in Connector/ODBC 3.51, but dynamic cursors are not enabled by default. You can enable this function within Windows by selecting the Enable Dynamic Cursor check box within the ODBC Data Source Administrator.

On other platforms, you can enable the dynamic cursor by adding 32 to the OPTION value when creating the DSN.

Connector/ODBC Performance

The Connector/ODBC driver has been optimized to provide very fast performance. If you experience problems with the performance of Connector/ODBC, or notice a large amount of disk activity for simple queries, there are a number of aspects to check:

Setting ODBC Query Timeout in Windows

For more information on how to set the query timeout on Microsoft Windows when executing queries through an ODBC connection, read the Microsoft knowledgebase document at http://support.microsoft.com/default.aspx?scid=kb%3Ben-us%3B153756.

Connector/ODBC Application-Specific Tips

Using Connector/ODBC with Microsoft Applications
Using Connector/ODBC with Borland Applications
Using Connector/ODBC with ColdFusion
Using Connector/ODBC with OpenOffice.org
Using Connector/ODBC with Sambar Server
Using Connector/ODBC with Pervasive Software DataJunction
Using Connector/ODBC with SunSystems Vision

Most programs should work with Connector/ODBC, but for each of those listed here, there are specific notes and tips to improve or enhance the way you work with Connector/ODBC and these applications.

With all applications, ensure that you are using the latest Connector/ODBC drivers, ODBC Manager and any supporting libraries and interfaces used by your application. For example, on Windows, using the latest version of Microsoft Data Access Components (MDAC) will improve the compatibility with ODBC in general, and with the Connector/ODBC driver.

Using Connector/ODBC with Microsoft Applications
Microsoft Access
Microsoft Excel and Column Types
Microsoft Visual Basic
Microsoft Visual InterDev
Visual Objects
Microsoft ADO
Using Connector/ODBC with Active Server Pages (ASP)
Using Connector/ODBC with Visual Basic (ADO, DAO and RDO) and ASP

The majority of Microsoft applications have been tested with Connector/ODBC, including Microsoft Office, Microsoft Access and the various programming languages supported within ASP and Microsoft Visual Studio.

Microsoft Access

To improve the integration between Microsoft Access and MariaDB through Connector/ODBC:

Some external articles and tips that may be useful when using Access, ODBC and Connector/ODBC:

Microsoft Excel and Column Types

If you have problems importing data into Microsoft Excel, particularly numeric, date, and time values, this is probably because of a bug in Excel, where the column type of the source data is used to determine the data type when that data is inserted into a cell within the worksheet. The result is that Excel incorrectly identifies the content and this affects both the display format and the data when it is used within calculations.

To address this issue, use the CONCAT() function in your queries. The use of CONCAT() forces Excel to treat the value as a string, which Excel will then parse and usually correctly identify the embedded information.

However, even with this option, some data may be incorrectly formatted, even though the source data remains unchanged. Use the Format Cells option within Excel to change the format of the displayed information.

Microsoft Visual Basic

To be able to update a table, you must define a primary key for the table.

Visual Basic with ADO cannot handle big integers. This means that some queries like SHOW PROCESSLIST do not work properly. The fix is to use OPTION=16384 in the ODBC connect string or to select the Change BIGINT columns to INT option in the Connector/ODBC connect screen. You may also want to select the Return matching rows option.

Microsoft Visual InterDev

If you have a BIGINT in your result, you may get the error [Microsoft][ODBC Driver Manager] Driver does not support this parameter. Try selecting the Change BIGINT columns to INT option in the Connector/ODBC connect screen.

Visual Objects

Select the Don't optimize column widths option.

Microsoft ADO

When you are coding with the ADO API and Connector/ODBC, you need to pay attention to some default properties that aren't supported by the MariaDB server. For example, using the CursorLocation Property as adUseServer returns a result of -1 for the RecordCount Property. To have the right value, you need to set this property to adUseClient, as shown in the VB code here: 

Dim myconn As New ADODB.Connection Dim myrs As New Recordset Dim mySQL As String Dim myrows As Long myconn.Open 'DSN=MyODBCsample'
mySQL = 'SELECT * from user'
myrs.Source = mySQL Set myrs.ActiveConnection = myconn myrs.CursorLocation = adUseClient myrs.Open myrows = myrs.RecordCount myrs.Close myconn.Close

Another workaround is to use a SELECT COUNT(*) statement for a similar query to get the correct row count.

To find the number of rows affected by a specific SQL statement in ADO, use the RecordsAffected property in the ADO execute method. For more information on the usage of execute method, refer to http://msdn.microsoft.com/library/default.asp?url=/library/en-us/ado270/htm/mdmthcnnexecute.asp.

For information, see ActiveX Data Objects(ADO) Frequently Asked Questions.

Using Connector/ODBC with Active Server Pages (ASP)

Select the Return matching rows option in the DSN.

For more information about how to access MariaDB through ASP using Connector/ODBC, refer to the following articles:

A Frequently Asked Questions list for ASP can be found at http://support.microsoft.com/default.aspx?scid=/Support/ActiveServer/faq/data/adofaq.asp.

Using Connector/ODBC with Visual Basic (ADO, DAO and RDO) and ASP

Some articles that may help with Visual Basic and ASP:

Using Connector/ODBC with Borland Applications
Using Connector/ODBC with Borland Builder 4
Using Connector/ODBC with Delphi
Using Connector/ODBC with C++ Builder

With all Borland applications where the Borland Database Engine (BDE) is used, follow these steps to improve compatibility:

Using Connector/ODBC with Borland Builder 4

When you start a query, you can use the Active property or the Open method. Note that Active starts by automatically issuing a SELECT * FROM ... query. That may not be a good thing if your tables are large.

Using Connector/ODBC with Delphi

Also, here is some potentially useful Delphi code that sets up both an ODBC entry and a BDE entry for Connector/ODBC. The BDE entry requires a BDE Alias Editor that is free at a Delphi Super Page near you. (Thanks to Bryan Brunton <bryan@flesherfab.com> for this): 

fReg:= TRegistry.Create;
fReg.OpenKey('\Software\ODBC\ODBC.INI\DocumentsFab', True);
fReg.WriteString('Database', 'Documents');
fReg.WriteString('Description', ' ');
fReg.WriteString('Driver', 'C:\WINNT\System32\myodbc.dll');
fReg.WriteString('Flag', '1');
fReg.WriteString('Password', '');
fReg.WriteString('Port', ' ');
fReg.WriteString('Server', 'xmark');
fReg.WriteString('User', 'winuser');
fReg.OpenKey('\Software\ODBC\ODBC.INI\ODBC Data Sources', True);
fReg.WriteString('DocumentsFab', 'MySQL');
fReg.CloseKey;
fReg.Free;
Memo1.Lines.Add('DATABASE NAME=");
Memo1.Lines.Add("USER NAME=");
Memo1.Lines.Add("ODBC DSN=DocumentsFab');
Memo1.Lines.Add('OPEN MODE=READ/WRITE');
Memo1.Lines.Add('BATCH COUNT=200');
Memo1.Lines.Add('LANGDRIVER=');
Memo1.Lines.Add('MAX ROWS=-1');
Memo1.Lines.Add('SCHEMA CACHE DIR=");
Memo1.Lines.Add("SCHEMA CACHE SIZE=8');
Memo1.Lines.Add('SCHEMA CACHE TIME=-1');
Memo1.Lines.Add('SQLPASSTHRU MODE=SHARED AUTOCOMMIT');
Memo1.Lines.Add('SQLQRYMODE=');
Memo1.Lines.Add('ENABLE SCHEMA CACHE=FALSE');
Memo1.Lines.Add('ENABLE BCD=FALSE');
Memo1.Lines.Add('ROWSET SIZE=20');
Memo1.Lines.Add('BLOBS TO CACHE=64');
Memo1.Lines.Add('BLOB SIZE=32');
AliasEditor.Add('DocumentsFab','MySQL',Memo1.Lines);
Using Connector/ODBC with C++ Builder

Tested with BDE 3.0. The only known problem is that when the table schema changes, query fields are not updated. BDE, however, does not seem to recognize primary keys, only the index named PRIMARY, although this has not been a problem.

Using Connector/ODBC with ColdFusion

The following information is taken from the ColdFusion documentation:

Use the following information to configure ColdFusion Server for Linux to use the unixODBC driver with Connector/ODBC for MariaDB data sources. You can download Connector/ODBC at http://dev.mysql.com/downloads/connector/odbc/.

ColdFusion version 4.5.1 lets you use the ColdFusion Administrator to add the MariaDB data source. However, the driver is not included with ColdFusion version 4.5.1. Before the MariaDB driver appears in the ODBC data sources drop-down list, you must build and copy the Connector/ODBC driver to /opt/coldfusion/lib/libmyodbc.so.

The Contrib directory contains the program mydsn-xxx.zip which lets you build and remove the DSN registry file for the Connector/ODBC driver on ColdFusion applications.

For more information and guides on using ColdFusion and Connector/ODBC, see the following external sites:

Using Connector/ODBC with OpenOffice.org

Open Office (http://www.openoffice.org) How-to: MariaDB + OpenOffice. How-to: OpenOffice + MyODBC + unixODBC.

Using Connector/ODBC with Sambar Server

Sambar Server (http://www.sambarserver.info) How-to: MyODBC + SambarServer + MySQL.

Using Connector/ODBC with Pervasive Software DataJunction

You have to change it to output VARCHAR rather than ENUM, as it exports the latter in a manner that causes MariaDB problems.

Using Connector/ODBC with SunSystems Vision

Select the Return matching rows option.

Connector/ODBC Errors and Resolutions (FAQ)

The following section details some common errors and their suggested fix or alternative solution. If you are still experiencing problems, use the Connector/ODBC mailing list; see , "Connector/ODBC Community Support".

Many problems can be resolved by upgrading your Connector/ODBC drivers to the latest available release. On Windows, make sure that you have the latest versions of the Microsoft Data Access Components (MDAC) installed.

Questions

Questions and Answers

21.1.7.3.1: I have installed Connector/ODBC on Windows XP x64 Edition or Windows Server 2003 R2 x64. The installation completed successfully, but the Connector/ODBC driver does not appear in ODBC Data Source Administrator.

This is not a bug, but is related to the way Windows x64 editions operate with the ODBC driver. On Windows x64 editions, the Connector/ODBC driver is installed in the %SystemRoot%\SysWOW64 folder. However, the default ODBC Data Source Administrator that is available through the Administrative Tools or Control Panel in Windows x64 Editions is located in the %SystemRoot%\system32 folder, and only searches this folder for ODBC drivers.

On Windows x64 editions, use the ODBC administration tool located at %SystemRoot%\SysWOW64\odbcad32.exe, this will correctly locate the installed Connector/ODBC drivers and enable you to create a Connector/ODBC DSN.

This issue was originally reported as Bug #20301.

21.1.7.3.2: When connecting or using the Test button in ODBC Data Source Administrator I get error 10061 (Cannot connect to server)

This error can be raised by a number of different issues, including server problems, network problems, and firewall and port blocking problems. For more information, see "Can't connect to [local] MariaDB server".

21.1.7.3.3: The following error is reported when using transactions: Transactions are not enabled

This error indicates that you are trying to use transactions with a MariaDB table that does not support transactions. Transactions are supported within MariaDB when using the InnoDB database engine. In versions of MariaDB before Mysql 5.1 you may also use the BDB engine.

Check the following before continuing:

21.1.7.3.4: Access reports records as #DELETED# when inserting or updating records in linked tables.

If the inserted or updated records are shown as #DELETED# in the access, then:

21.1.7.3.5: How do I handle Write Conflicts or Row Location errors?

If you see the following errors, select the Return Matching Rows option in the DSN configuration dialog, or specify OPTION=2, as the connection parameter: 

Write Conflict. Another user has changed your data.
Row cannot be located for updating. Some values may have been changed since it was last read.

21.1.7.3.6: Exporting data from Access 97 to MariaDB reports a Syntax Error.

This error is specific to Access 97 and versions of Connector/ODBC earlier than 3.51.02. Update to the latest version of the Connector/ODBC driver to resolve this problem.

21.1.7.3.7: Exporting data from Microsoft DTS to MariaDB reports a Syntax Error.

This error occurs only with MariaDB tables using the TEXT or VARCHAR data types. You can fix this error by upgrading your Connector/ODBC driver to version 3.51.02 or higher.

21.1.7.3.8: Using ODBC.NET with Connector/ODBC, while fetching empty string (0 length), it starts giving the SQL_NO_DATA exception.

You can get the patch that addresses this problem from http://support.microsoft.com/default.aspx?scid=kb;EN-US;q319243.

21.1.7.3.9: Using SELECT COUNT(*) FROM tbl_name within Visual Basic and ASP returns an error.

This error occurs because the COUNT(*) expression is returning a BIGINT, and ADO cannot make sense of a number this big. Select the Change BIGINT columns to INT option (option value 16384).

21.1.7.3.10: Using the AppendChunk() or GetChunk() ADO methods, the Multiple-step operation generated errors. Check each status value error is returned.

The GetChunk() and AppendChunk() methods from ADO doesn't work as expected when the cursor location is specified as adUseServer. On the other hand, you can overcome this error by using adUseClient.

A simple example can be found from http://www.dwam.net/iishelp/ado/docs/adomth02_4.htm

21.1.7.3.11: Access Returns Another user had modified the record that you have modified while editing records on a Linked Table.

In most cases, this can be solved by doing one of the following things:

If these strategies do not help, start by making a log file from the ODBC manager (the log you get when requesting logs from ODBCADMIN) and a Connector/ODBC log to help you figure out why things go wrong. For instructions, see , "Getting an ODBC Trace File".

21.1.7.3.12: When linking an application directly to the Connector/ODBC library under Unix/Linux, the application crashes.

Connector/ODBC 3.51 under Unix/Linux is not compatible with direct application linking. You must use a driver manager, such as iODBC or unixODBC to connect to an ODBC source.

21.1.7.3.13: Applications in the Microsoft Office suite are unable to update tables that have DATE or TIMESTAMP columns.

This is a known issue with Connector/ODBC. You must ensure that the field has a default value (rather than NULL and that the default value is nonzero (that is, the default value is not 0000-00-00 00:00:00).

21.1.7.3.14: When connecting Connector/ODBC 5.x (Beta) to a MariaDB 4.x server, the error 1044 Access denied for user 'xxx'@'%' to database 'information_schema' is returned.

Connector/ODBC 5.x is designed to work with MariaDB 5.0 or later, taking advantage of the INFORMATION_SCHEMA database to determine data definition information. Support for MariaDB is planned for the final release.

21.1.7.3.15: When calling SQLTables, the error S1T00 is returned, but I cannot find this in the list of error numbers for Connector/ODBC.

The S1T00 error indicates that a general timeout has occurred within the ODBC system and is not a MariaDB error. Typically it indicates that the connection you are using is stale, the server is too busy to accept your request or that the server has gone away.

21.1.7.3.16: When linking to tables in Access 2000 and generating links to tables programmatically, rather than through the table designer interface, you may get errors about tables not existing.

There is a known issue with a specific version of the msjet40.dll that exhibits this issue. The version affected is 4.0.9025.0. Reverting to an older version will enable you to create the links. If you have recently updated your version, check your WINDOWS directory for the older version of the file and copy it to the drivers directory.

21.1.7.3.17: When I try to use batched statements, the execution of the batched statements fails.

Batched statement support was added in 3.51.18. Support for batched statements is not enabled by default. You must enable option FLAG_MULTI_STATEMENTS, value 67108864, or select the Allow multiple statements flag within a GUI configuration.

21.1.7.3.18: When connecting to a MariaDB server using ADODB and Excel, occasionally the application fails to communicate with the server and the error Got an error reading communication packets appears in the error log.

This error may be related to Keyboard Logger 1.1 from PanteraSoft.com, which is known to interfere with the network communication between MariaDB Connector/ODBC and MySQL.

21.1.7.3.19: When using some applications to access a MariaDB server using C/ODBC and outer joins, an error is reported regarding the Outer Join Escape Sequence.

This is a known issue with MariaDB Connector/ODBC which is not correctly parsing the 'Outer Join Escape Sequence', as per the specs at Microsoft ODBC Specs. Currently, Connector/ODBC will return value > 0 when asked for SQL_OJ_CAPABILITIES even though no parsing takes place in the driver to handle the outer join escape sequence.

21.1.7.3.20: I can correctly store extended characters in the database (Hebrew/CJK) using C/ODBC 5.1, but when I retrieve the data, the text is not formatted correctly and I get garbled characters.

When using ASP and UTF8 characters, add the following to your ASP files to ensure that the data returned is correctly encoded: 

Response.CodePage = 65001
Response.CharSet = 'utf-8'

21.1.7.3.21: I have a duplicate MariaDB Connector/ODBC entry within my Installed Programs list, but I cannot delete one of them.

This problem can occur when you upgrade an existing Connector/ODBC installation, rather than removing and then installing the updated version.Warning

To fix the problem, use any working uninstallers to remove existing installations and then may have to edit the contents of the registry. Make sure you have a backup of your registry information before attempting any editing of the registry contents.

21.1.7.3.22: When submitting queries with parameter binding using UPDATE, my field values are being truncated to 255 characters.

Ensure that the FLAG_BIG_PACKETS option is set for your connection. This removes the 255 character limitation on bound parameters.

21.1.7.3.23: Is it possible to disable data-at-execution using a flag?

If you do not want to use data-at-execution, simply remove the corresponding calls. For example: 

SQLLEN ylen = SQL_LEN_DATA_AT_EXEC(10);
SQLBindCol(hstmt,2,SQL_C_BINARY, buf, 10, &ylen);

Would become: 

SQLBindCol(hstmt,2,SQL_C_BINARY, buf, 10, NULL);

Note that in the call to SQLBindCol(), &ylen has been replaced by NULL.

For further information please refer to the MSDN documentation for SQLBindCol().

21.1.7.3.24: When you call SQLColumns() for a table column that is AUTO_INCREMENT, the NULLABLE column of the result set is always SQL_NULLABLE (1).

This is because MariaDB reports the DEFAULT value for such a column as NULL. It means, if you insert a NULL value into the column, you will get the next integer value for the table's auto_increment counter.

Connector/ODBC Support

Connector/ODBC Community Support
How to Report Connector/ODBC Problems or Bugs
How to Submit a Connector/ODBC Patch
Connector/ODBC Change History
Credits

There are many different places where you can get support for using Connector/ODBC. Always try the Connector/ODBC Mailing List or Connector/ODBC Forum. See , "Connector/ODBC Community Support", for help before reporting a specific bug or issue to MariaDB.

Connector/ODBC Community Support

Oracle provides assistance to the user community by means of its mailing lists. For Connector/ODBC-related issues, you can get help from experienced users by using the <myodbc@lists.mysql.com> mailing list. Archives are available online at http://lists.mysql.com/myodbc.

For information about subscribing to MariaDB mailing lists or to browse list archives, visit http://lists.mysql.com/. See , "MySQL Mailing Lists".

Community support from experienced users is also available through the ODBC Forum. You may also find help from other users in the other MariaDB Forums, located at http://forums.mysql.com. See , "MySQL Community Support at the MariaDB Forums".

How to Report Connector/ODBC Problems or Bugs

If you encounter difficulties or problems with Connector/ODBC, start by making a log file from the ODBC Manager (the log you get when requesting logs from ODBC ADMIN) and Connector/ODBC. The procedure for doing this is described in , "Getting an ODBC Trace File".

Check the Connector/ODBC trace file to find out what could be wrong. Determine what statements were issued by searching for the string >mysql_real_query in the myodbc.log file.

Also, try issuing the statements from the mysql client program or from admndemo. This helps you determine whether the error is in Connector/ODBC or MySQL.

If you find out something is wrong, please only send the relevant rows (maximum 40 rows) to the myodbc mailing list. See , "MySQL Mailing Lists". Please never send the whole Connector/ODBC or ODBC log file!

Ideally, include the following information with the email:

Remember that the more information you can supply to us, the more likely it is that we can fix the problem!

Also, before posting the bug, check the MyODBC mailing list archive at http://lists.mysql.com/myodbc.

If you are unable to find out what is wrong, the last option is to create an archive in tar or Zip format that contains a Connector/ODBC trace file, the ODBC log file, and a README file that explains the problem. You can send this to ftp://ftp.mysql.com/pub/mysql/upload/. Only MariaDB engineers have access to the files you upload, and we are very discreet with the data.

If you can create a program that also demonstrates the problem, please include it in the archive as well.

If the program works with another SQL server, include an ODBC log file where you perform exactly the same SQL statements so that we can compare the results between the two systems.

Remember that the more information you can supply to us, the more likely it is that we can fix the problem.

How to Submit a Connector/ODBC Patch

You can send a patch or suggest a better solution for any existing code or problems by sending a mail message to <myodbc@lists.mysql.com>.

Connector/ODBC Change History

The Connector/ODBC Change History (Changelog) is located with the main Changelog for MySQL. See "MySQL Connector/ODBC (MyODBC) Change History".

Credits

These are the developers that have worked on the Connector/ODBC and Connector/ODBC 3.51 Drivers from MariaDB Foundation.

MySQL Connector/Net

Connector/Net Versions
Connector/Net Installation
Connector/Net Visual Studio Integration
Connector/Net Tutorials
Connector/Net Programming
Connector/Net Connection String Options Reference
Connector/Net API Reference
Connector/Net Support
Connector/Net FAQ

Connector/Net lets you easily develop .NET applications that require secure, high-performance data connectivity with MySQL. It implements the required ADO.NET interfaces and integrates into ADO.NET aware tools. Developers can build applications using their choice of .NET languages. Connector/Net is a fully managed ADO.NET driver written in 100% pure C#.

Connector/Net includes full support for:

This document is intended as a user's guide to Connector/Net and includes a full syntax reference. Syntax information is also included within the Documentation.chm file included with the Connector/Net distribution.

If you are using MariaDB 5.0 or later, and Visual Studio as your development environment, you can also use the MariaDB Visual Studio Plugin. The plugin acts as a DDEX (Data Designer Extensibility) provider: you can use the data design tools within Visual Studio to manipulate the schema and objects within a MariaDB database. For more information, see , "Connector/Net Visual Studio Integration".Note

Connector/Net 5.1.2 and later include the Visual Studio Plugin by default.

MySQL Connector/Net supports full versions of Visual Studio 2005, 2008, and 2010, although certain features are only available in Visual Studio 2010 when using MariaDB Connector/Net version 6.3.2 and later. Note that MariaDB Connector/Net does not currently support Express versions of Microsoft products, including Microsoft Visual Web Developer.

Key topics:

Connector/Net Versions

There are several versions of Connector/Net available:

The latest source code for Connector/Net can be downloaded from the MariaDB public Subversion server. For further details, see , "Installing Connector/Net from the source code".

The following tables shows the .NET Framework version required, and the MariaDB Server version supported by Connector/Net:

Table 20.5. Connector/Net Requirements for Related Products

Connector/Net version ADO.NET version supported .NET Framework version required MySQL Server version supported Currently supported
6.4 2.x+ 2.x+, 4.x+ for VS 2010 support 5.5, 5.1, 5.0 Yes
6.3 2.x+ 2.x+, 4.x+ for VS 2010 support 5.5, 5.1, 5.0 Yes
6.2 2.x+ 2.x+ 5.5, 5.1, 5.0, 4.1 Yes
6.1 2.x+ 2.x+ 5.5, 5.1, 5.0, 4.1 Yes
6.0 2.x+ 2.x+ 5.5, 5.1, 5.0, 4.1 Critical issues only
5.2 2.x+ 2.x+ 5.5, 5.1, 5.0, 4.1 No
5.1 2.x+ 2.x+ 5.5, 5.1, 5.0, 4.1, 4.0 No
5.0 2.x+ 2.x+ 5.0, 4.1, 4.0 No
1.0 1.x 1.x 5.0, 4.1, 4.0 No
Note

Version numbers for MariaDB products are formatted as X.Y.Z, where Z=0 indicates alpha, Z=1 indicates beta, and Z>=2 indicates GA. However, Windows tools (Control Panel, properties display) may show the version numbers as XX.YY.ZZ. For example, the official MariaDB formatted version number 5.0.9 may be displayed by Windows tools as 5.00.09. The two versions are the same; only the number display format is different.

Connector/Net Installation

Installing Connector/Net on Windows
Installing Connector/Net on Unix with Mono
Installing Connector/Net from the source code

Connector/Net runs on any platform that supports the .NET framework. The .NET framework is primarily supported on recent versions of Microsoft Windows, and is supported on Linux through the Open Source Mono framework (see http://www.mono-project.com).

Connector/Net is available for download from http://dev.mysql.com/downloads/connector/net/.

Installing Connector/Net on Windows

Installing Connector/Net using the Installer
Installing Connector/Net using the Zip packages

On Windows, installation is supported either through a binary installation process or by downloading a Zip file with the Connector/Net components.

Before installing, ensure that your system is up to date, including installing the latest version of the .NET Framework.

Installing Connector/Net using the Installer

Using the installer is the most straightforward method of installing Connector/Net on Windows and the installed components include the source code, test code and full reference documentation.

Connector/Net is installed through the use of a Windows Installer (.msi) installation package, which can be used to install Connector/Net on all Windows operating systems. The MSI package in contained within a Zip archive named mysql-connector-net-version.zip, where version indicates the Connector/Net version.

To install Connector/Net:

  1. Double-click the MSI installer file extracted from the Zip you downloaded. Click Next to start the installation.

    Connector/Net Windows Installer - Welcome
  2. You must choose the type of installation to perform.Connector/Net Windows Installer - Installation type

    For most situations, the Typical installation is suitable. Click the Typical button and proceed to Step 5. A Complete installation installs all the available files. To conduct a Complete installation, click the Complete button and proceed to step 5. To customize your installation, including choosing the components to install and some installation options, click the Custom button and proceed to Step 3.

    The Connector/Net installer will register the connector within the Global Assembly Cache (GAC) - this will make the Connector/Net component available to all applications, not just those where you explicitly reference the Connector/Net component. The installer will also create the necessary links in the Start menu to the documentation and release notes.

  3. If you have chosen a custom installation, you can select the individual components to install, including the core interface component, supporting documentation (a CHM file) samples and examples, and the source code. Select the items, and their installation level, and then click Next to continue the installation.Note

    For Connector/Net 1.0.8 or lower and Connector 5.0.4 and lower the installer will attempt to install binaries for both 1.x and 2.x of the .NET Framework. If you only have one version of the framework installed, the connector installation may fail. If this happens, you can choose the framework version to be installed through the custom installation step.Connector/Net Windows Installer - Custom setup

  4. You will be given a final opportunity to confirm the installation. Click Install to copy and install the files onto your machine.Connector/Net Windows Installer - Confirming installation
  5. Once the installation has been completed, click Finish to exit the installer.Connector/Net Windows Installer - Finish installation

Unless you choose otherwise, Connector/Net is installed in C:\Program Files\MySQL\MySQL Connector Net X.X.X, where X.X.X is replaced with the version of Connector/Net you are installing. New installations do not overwrite existing versions of Connector/Net.

Depending on your installation type, the installed components will include some or all of the following components:

You may also use the /quiet or /q command-line option with the msiexec tool to install the Connector/Net package automatically (using the default options) with no notification to the user. Using this method the user cannot select options. Additionally, no prompts, messages or dialog boxes will be displayed. 

C:\> msiexec /package connector-net.msi /quiet

To provide a progress bar to the user during automatic installation, use the /passive option.

Installing Connector/Net using the Zip packages

If you are having problems running the installer, you can download a Zip file without an installer as an alternative. That file is called mysql-connector-net-version-noinstall.zip. Once downloaded, you can extract the files to a location of your choice.

The file contains the following directories:

Connector/Net 6.0.x has a different directory structure:

There is also another Zip file available for download called mysql-connector-net-version-src.zip. This file contains the source code distribution.

The file contains the following directories:

Finally, ensure that MySql.Data.dll is accessible to your program at build time (and run time). If using Microsoft Visual Studio, add MySql.Data as a Reference to your project.Note

If using MariaDB Connector/Net 6.3.5 and above, the MySql.Data file provided will work with both .NET Framework 2.x and 4.x.

Installing Connector/Net on Unix with Mono

There is no installer available for installing the Connector/Net component on your Unix installation. Before installing, please ensure that you have a working Mono project installation. You can test whether your system has Mono installed by typing: 

shell> mono --version

The version of the Mono JIT compiler is displayed.

To compile C# source code, make sure a Mono C# compiler is installed. Note that there are two Mono C# compilers available, mcs, which accesses the 1.0-profile libraries, and gmcs, which accesses the 2.0-profile libraries.

To install Connector/Net on Unix/Mono:

  1. Download the mysql-connector-net-version-noinstall.zip and extract the contents to a directory of your choice, for example: ~/connector-net/.
  2. In the directory where you unzipped the connector to, change into the bin directory. Ensure the file MySql.Data.dll is present.
  3. You must register the Connector/Net component, MySql.Data, in the Global Assembly Cache (GAC). In the current directory enter the gacutil command: 
    root-shell> gacutil /i MySql.Data.dll

    This will register MySql.Data into the GAC. You can check this by listing the contents of /usr/lib/mono/gac, where you will find MySql.Data if the registration has been successful.

You are now ready to compile your application. You must ensure that when you compile your application you include the Connector/Net component using the -r: command-line option. For example: 

shell> gmcs -r:System.dll -r:System.Data.dll -r:MySql.Data.dll HelloWorld.cs

Note, the assemblies that are referenced depend on the requirements of the application, but applications using Connector/Net must provide -r:MySql.Data as a minimum.

You can further check your installation by running the compiled program, for example: 

shell> mono HelloWorld.exe

Installing Connector/Net from the source code

Caution

Read this section only if you are interested in helping us test our new code. If you just want to get Connector/Net up and running on your system, use a standard release distribution.

Obtaining the source code

To obtain the most recent development source tree, you first need to download and install Bazaar. You can obtain Bazaar from the Bazaar VCS Website. Bazaar is supported by any platform that supports Python, and is therefore compatible with any Linux, Unix, Windows or Mac OS X host. Instructions for downloading and installing Bazaar on the different platforms are available on the Bazaar Web site.

The most recent development source tree is available from our public Subversion trees at http://dev.mysql.com/tech-resources/sources.html.

To check out out the Connector/Net sources, change to the directory where you want the copy of the Connector/Net tree to be stored, then use the following command: 

shell> bzr branch lp:connectornet/trunk

To download a specific version of Connector/Net, specify the version number instead of trunk. For example, to obtain a copy of the 6.0 version of the source tree: 

shell> bzr branch lp:connectornet/6.0

Source packages are also available on the downloads page.

Building the source code on Windows

The following procedure can be used to build the connector on Microsoft Windows.

Building the source code on Unix

Support for building Connector/Net on Mono/Unix is currently not available.

Connector/Net Visual Studio Integration

Making a Connection
Using IntelliSense in the SQL Editor
Editing Tables
Editing Views
Editing Stored Procedures and Functions
Editing Triggers
Editing User Defined Functions (UDF)
Cloning Database Objects
Dropping Database Objects
Using the ADO.NET Entity Framework
MySQL Website Configuration Tool
MySQL SQL Editor
DDL T4 Template Macro

When MariaDB Connector/Net is installed on Microsoft Windows, Visual Studio integration components are also installed and initialized. This enables the developer to work seamlessly with MariaDB Connector/Net in the familiar Visual Studio environment, as described in the following sections of the manual.

MySQL Connector/Net supports Visual Studio versions 2005, 2008, and 2010. However, only MariaDB Connector/Net version 6.3 and higher fully integrate with Visual Studio 2010, although applications using earlier versions of the connector can be built with the Visual Studio 2010 environment using .NET 2.x frameworks.

Visual Studio 2010 support was introduced with MariaDB Connector/Net 6.3.2. From version 6.3.2 the connector ships with both .NET 2.x and .NET 4.x versions of the entity framework support files, mysql.data.ef.dll and mysql.visualstudio.dll. The .NET 4.x versions are required to enable new integration features supported in Visual Studio 2010, including:

Making a Connection

Once the connector is installed, you can use it to create, modify, and delete connections to MariaDB databases. To create a connection with a MariaDB database, perform the following steps:

After the connection is successfully established, all settings are saved for future use. When you start Visual Studio for the next time, open the connection node in Server Explorer to establish a connection to the MariaDB server again.

To modify and delete a connection, use the Server Explorer context menu for the corresponding node. You can modify any of the settings by overwriting the existing values with new ones. Note that the connection may be modified or deleted only if no active editor for its objects is opened: otherwise, you may lose your data.

Using IntelliSense in the SQL Editor

IntelliSense support is available starting in Connector/Net 6.5. Once you have established a connection, for example, using the Connect to MySql toolbar button, you can get autocompletion as you type, or by pressing Control+J. Depending on the context, the autocompletion dialog can show the list of available tables, table columns, or stored procedures (with the routine's signature as a tooltip). Typing some characters before pressing Control+J filters the choices to those items starting with that prefix.

Editing Tables

Column Editor
Editing Indexes
Editing Foreign Keys
Column Properties
Table Properties

Connector/Net contains a table editor, which enables the visual creation and modification of tables.

The Table Designer can be accessed through a mouse action on table-type node of Server Explorer. To create a new table, right-click the Tables node (under the connection node) and choose the Create Table command from the context menu.

To modify an existing table, double-click the node of the table to modify, or right-click this node and choose the Design item from the context menu. Either of the commands opens the Table Designer.

The table editor is implemented in the manner of the well-known Query Browser Table Editor, but with minor differences.

Figure 20.5. Editing New Table

Editing New Table

Table Designer consists of the following parts:

Each of these areas is discussed in more detail in subsequent sections.

To save changes you have made in the Table Designer, use either Save or Save All button of the Visual Studio main toolbar, or press Control+S. If you have not already named the table, you will be prompted to do so.

Figure 20.6. Choose Table Name

Choose Table Name

Once the table is created, you can view it in the Server Explorer.

Figure 20.7. Newly Created Table

Newly Created Table

The Table Designer main menu enables you to set a Primary Key column, edit Relationships such as Foreign Keys, and create Indexes.

Figure 20.8. Table Designer Main Menu

Table Designer Main Menu
Column Editor

You can use the Column Editor to set or change the name, data type, default value, and other properties of a table column. To set the focus to a needed cell of a grid, use the mouse click. Also you can move through the grid using Tab and Shift+Tab keys.

To set or change the name, data type, default value and comment of a column, activate the appropriate cell and type the desired value.

To set or unset flag-type column properties (NOT NULL, auto incremented, flags), check or uncheck the corresponding check boxes. Note that the set of column flags depends on its data type.

To reorder columns, index columns or foreign key columns in the Column Editor, select the whole column to reorder by clicking the selector column on the left of the column grid. Then move the column by using Control+Up (to move the column up) or Control+Down (to move the column down) keys.

To delete a column, select it by clicking the selector column on the left of the column grid, then press the Delete button on a keyboard.

Editing Indexes

Indexes management is performed using the Indexes/Keys dialog.

To add an index, select Table Designer, Indexes/Keys... from the main menu, and click Add to add a new index. You can then set the index name, index kind, index type, and a set of index columns.

Figure 20.9. Indexes Dialog

Indexes Dialog

To remove an index, select it in the list box on the left, and click the Delete button.

To change index settings, select the needed index in the list box on the left. The detailed information about the index is displayed in the panel on the right hand side. Change the desired values.

Editing Foreign Keys

Foreign Keys management is performed using the Foreign Key Relationships dialog.

To add a foreign key, select Table Designer, Relationships... from the main menu. This displays the Foreign Key Relationship dialog. Click Add. You can then set the foreign key name, referenced table name, foreign key columns, and actions upon update and delete.

To remove a foreign key, select it in the list box on the left, and click the Delete button.

To change foreign key settings, select the required foreign key in the list box on the left. The detailed information about the foreign key is displayed in the right hand panel. Change the desired values.

Figure 20.10. Foreign Key Relationships Dialog

Foreign Key Relationships Dialog
Column Properties

The Column Properties tab can be used to set column options. In addition to the general column properties presented in the Column Editor, in the Column Properties tab you can set additional properties such as Character Set, Collation and Precision.

Table Properties

To bring up Table Properties select the table and right-click to activate the context menu. Select Properties. The Table Properties dockable window will be displayed.

Figure 20.11. Table Properties Menu Item

Table Properties Menu Item

The following table properties can be set:

The property Schema is read-only.

Figure 20.12. Table Properties

Table Properties

Editing Views

To create a new view, right-click the Views node under the connection node in Server Explorer. From the node's context menu, choose the Create View command. This command opens the SQL Editor.

Figure 20.13. Editing View SQL

Editing View SQL

You can then enter the SQL for your view.

Figure 20.14. View SQL Added

View SQL Added

To modify an existing view, double-click a node of the view to modify, or right-click this node and choose the Alter View command from a context menu. Either of the commands opens the SQL Editor.

All other view properties can be set in the Properties window. These properties are:

Some of these properties can have arbitrary text values, others accept values from a predefined set. In the latter case, set the desired value with an embedded combobox.

The properties Is Updatable and Schema are readonly.

To save changes you have made, use either Save or Save All buttons of the Visual Studio main toolbar, or press Control+S.

Figure 20.15. View SQL Saved

View SQL Saved

Editing Stored Procedures and Functions

To create a new stored procedure, right-click the Stored Procedures node under the connection node in Server Explorer. From the node's context menu, choose the Create Routine command. This command opens the SQL Editor.

Figure 20.16. Edit Stored Procedure SQL

Edit Stored Procedure SQL

To create a new stored function, right-click the Functions node under the connection node in Server Explorer. From the node's context menu, choose the Create Routine command.

To modify an existing stored routine (procedure or function), double-click the node of the routine to modify, or right-click this node and choose the Alter Routine command from the context menu. Either of the commands opens the SQL Editor.

To create or alter the routine definition using SQL Editor, type this definition in the SQL Editor using standard SQL. All other routine properties can be set in the Properties window. These properties are:

Some of these properties can have arbitrary text values, others accept values from a predefined set. In the latter case, set the desired value using the embedded combo box.

You can also set all the options directly in the SQL Editor, using the standard CREATE PROCEDURE or CREATE FUNCTION statement. However, it is recommended to use the Properties window instead.

To save changes you have made, use either Save or Save All buttons of the Visual Studio main toolbar, or press Control+S.

Figure 20.17. Stored Procedure SQL Saved

Stored Procedure SQL Saved

Editing Triggers

To create a new trigger, right-click the node of the table in which to add the trigger. From the node's context menu, choose the Create Trigger command. This command opens the SQL Editor.

To modify an existing trigger, double-click the node of the trigger to modify, or right-click this node and choose the Alter Trigger command from the context menu. Either of the commands opens the SQL Editor.

To create or alter the trigger definition using SQL Editor, type the trigger statement in the SQL Editor using standard SQL.Note

Enter only the trigger statement, that is, the part of the CREATE TRIGGER query that is placed after the FOR EACH ROW clause.

All other trigger properties are set in the Properties window. These properties are:

Some of these properties can have arbitrary text values, others accept values from a predefined set. In the latter case, set the desired value using the embedded combo box.

The properties Event Table, Schema, and Server in the Properties window are read-only.

To save changes you have made, use either Save or Save All buttons of the Visual Studio main toolbar, or press Control+S. Before changes are saved, you will be asked to confirm the execution of the corresponding SQL query in a confirmation dialog.

Editing User Defined Functions (UDF)

To create a new User Defined Function (UDF), right-click the UDFs node under the connection node in Server Explorer. From the node's context menu, choose the Create UDF command. This command opens the UDF Editor.

To modify an existing UDF, double-click the node of the UDF to modify, or right-click this node and choose the Alter UDF command from the context menu. Either of these commands opens the UDF Editor.

The UDF editor enables you to set the following properties:

There are text fields for both names, a combo box for the return type, and a check box to indicate if the UDF is aggregate. All these options are also accessible using the Properties window.

The property Server in the Properties window is read-only.

To save changes you have made, use either Save or Save All buttons of the Visual Studio main toolbar, or press Control+S. Before changes are saved, you will be asked to confirm the execution of the corresponding SQL query in a confirmation dialog.

Cloning Database Objects

Tables, views, stored procedures, and functions can be cloned using the appropriate Clone command from the context menu: Clone Table, Clone View, Clone Routine. The clone commands open the corresponding editor for a new object: the Table Editor for cloning a table, and the SQL Editor for cloning a view or a routine.

The editor is filled with values of the original object. You can modify these values in a usual manner.

To save the cloned object, use either Save or Save All buttons of the Visual Studio main toolbar, or press Control+S. Before changes are saved, you will be asked to confirm the execution of the corresponding SQL query in a confirmation dialog.

Dropping Database Objects

Tables, views, stored routines, triggers, and UDFs can be dropped with the appropriate Drop command selected from its context menu: Drop Table, Drop View, Drop Routine, Drop Trigger, Drop UDF.

You will be asked to confirm the execution of the corresponding drop query in a confirmation dialog.

Dropping of multiple objects is not supported.

Using the ADO.NET Entity Framework

Connector/Net 6.0 introduced support for the ADO.NET Entity Framework. ADO.NET Entity Framework was included with .NET Framework 3.5 Service Pack 1, and Visual Studio 2008 Service Pack 1. ADO.NET Entity Framework was released on 11th August 2008.

ADO.NET Entity Framework provides an Object Relational Mapping (ORM) service, mapping the relational database schema to objects. The ADO.NET Entity Framework defines several layers, these can be summarized as:

Connector/Net integrates with Visual Studio 2008 to provide a range of helpful tools to assist the developer.

A full treatment of ADO.NET Entity Framework is beyond the scope of this manual. If you are unfamiliar with ADO.NET, review the Microsoft ADO.NET Entity Framework documentation.

Tutorials on getting started with ADO.NET Entity Framework are available. See , "Tutorial: Using an Entity Framework Entity as a Windows Forms Data Source" and , "Tutorial: Databinding in ASP.NET using LINQ on Entities".

MySQL Website Configuration Tool

MySQL Connector/Net 6.1 introduced the MariaDB Website Configuration Tool. This is a facility available in Visual Studio that enables you to configure the Membership, Role, Session State and Profile Provider, without having to resort to editing configuration files. You set your configuration options within the tool, and the tool modifies your web.config file accordingly.

The MariaDB Website Configuration Tool appears as a small icon on the Solution Explorer toolbar in Visual Studio, as show by the following screenshot:

Figure 20.18. MariaDB Website Configuration Tool

MySQL Website Configuration Tool

Clicking the Website Configuration Tool icon launches the wizard and displays the first screen:

Figure 20.19. MariaDB Website Configuration Tool - Membership

MySQL Website Configuration Tool - Membership

This allows you to enable use of the MariaDB Membership Provider. Click the check box to enable this. You can now enter the name of the application that you are creating the configuration for. You can also enter a description for the application.

You can then click the Edit... button to launch the Connection String Editor:

Figure 20.20. MariaDB Website Configuration Tool - Connection String Editor

MySQL Website Configuration Tool - Connection String Editor

Note that if you have already defined a connection string for the providers manually in web.config, or previously using the tool, this will be automatically loaded and displayed, and can then be modified in this dialog.

You can also ensure that the necessary schemas are created automatically for you by selecting the Autogenerate Schema check box. These schemas are used to store membership information. The database used to storage is the one specified in the connection string.

You can also ensure that exceptions generated by the application will be written to the event log by selecting the Write exceptions to event log check box.

Clicking the Advanced... button launches a dialog that enables you to set Membership Options. These options dictate such variables as password length required when a user signs up, whether the password is encrypted and whether the user can reset their password or not.

Figure 20.21. MariaDB Website Configuration Tool - Advanced Options

MySQL Website Configuration Tool - Advanced Options

Once information has been set up as required for configuration of the Membership Provider, the Next button can be clicked to display the Roles Provider screen:

Figure 20.22. MariaDB Website Configuration Tool - Roles

MySQL Website Configuration Tool - Roles

Again the connection string can be edited, a description added and Autogenerate Schema can be enabled before clicking Next to go to the Profiles Provider screen:

Figure 20.23. MariaDB Website Configuration Tool - Profiles

MySQL Website Configuration Tool - Profiles

This screen display similar options to the previous screens.

Click Next to proceed to the Session State configuration page:

Figure 20.24. MariaDB Website Configuration Tool - Session State

MySQL Website Configuration Tool - Session State

Once you have set up the Session State Provider as required, click Finish to exit the wizard.

At this point, it is necessary to select the Authentication Type to From Internet. Launch the ASP.NET Configuration Tool and select the Security tab. Click the Select authentication type link and ensure that the From the internet radio button is selected. You can now examine the database you created to store membership information. All the necessary tables will have been created for you:

Figure 20.25. MariaDB Website Configuration Tool - Tables

MySQL Website Configuration Tool - Tables

MySQL SQL Editor

MySQL Connector/Net 6.3.2 introduced a new MariaDB SQL Editor. The easiest way to invoke the editor is by selecting the New, File menu item from the Visual Studio main menu. This displays the New File dialog:

Figure 20.26. MariaDB SQL Editor - New File

MySQL SQL Editor - New File

From the New File dialog, select the MariaDB template, and then double-click the MariaDB SQL Script document, or click the Open button.

The MariaDB SQL Editor will be displayed. You can now enter SQL code as required, or connect to a MariaDB server. Click the Connect to MariaDB button in the MariaDB SQL Editor toolbar. You can enter the connection details into the Connect to MariaDB dialog that is displayed. You can enter the server name, user ID, password and database to connect to, or click the Advanced button to select other connection string options. Click the Connect button to connect to the MariaDB server. To execute your SQL code against the server, click the Run SQL button on the toolbar.

Figure 20.27. MariaDB SQL Editor - Query

MySQL SQL Editor - Query

The results from any queries are displayed on the Results tab. Any errors are displayed on the Messages tab.

DDL T4 Template Macro

MySQL Connector/Net 6.3 introduced the ability to convert an Entity Framework model to MariaDB DDL code. Starting with a blank model, an entity model can be developed in Visual Studio's designer. Once the model has been created, the model's properties can be selected, and in the Database Script Generation category of the model's properties, the property DDL Generation can be found. The value SSDLToMySQL.tt(VS) can then be selected from the drop-down listbox.

Figure 20.28. DDL T4 Template Macro - Model Properties

DDL T4 Template Macro - Model Properties

Right-clicking the model design area will display a context-sensitive menu. Selecting Generate Database from Model from the menu will display the Generate Database Wizard. The wizard can then be used to generate MariaDB DDL code.

Figure 20.29. DDL T4 Template Macro - Generate Database Wizard

DDL T4 Template Macro - Generate Database Wizard

Connector/Net Tutorials

Tutorial: An Introduction to Connector/Net Programming
Tutorial: MariaDB Connector/Net ASP.NET Membership and Role Provider
Tutorial: MariaDB Connector/Net ASP.NET Session State Provider
Tutorial: MariaDB Connector/Net ASP.NET Profile Provider
Tutorial: Using an Entity Framework Entity as a Windows Forms Data Source
Tutorial: Databinding in ASP.NET using LINQ on Entities
Tutorial: Using SSL with MariaDB Connector/Net
Tutorial: Using MySqlScript
Tutorial: Generating MariaDB DDL from an Entity Framework Model

Tutorial: An Introduction to Connector/Net Programming

The MySqlConnection Object
The MySqlCommand Object
Working with Decoupled Data
Working with Parameters
Working with Stored Procedures

This section provides a gentle introduction to programming with Connector/Net. The example code is written in C#, and is designed to work on both Microsoft .NET Framework and Mono.

This tutorial is designed to get you up and running with Connector/Net as quickly as possible, it does not go into detail on any particular topic. However, the following sections of this manual describe each of the topics introduced in this tutorial in more detail. In this tutorial you are encouraged to type in and run the code, modifying it as required for your setup.

This tutorial assumes you have MariaDB and Connector/Net already installed. It also assumes that you have installed the World example database, which can be downloaded from the MySQL Documentation page. You can also find details on how to install the database on the same page.Note

Before compiling the example code, make sure that you have added References to your project as required. The References required are System, System.Data and MySql.Data.

The MySqlConnection Object

For your Connector/Net application to connect to a MariaDB database, it must establish a connection by using a MySqlConnection object.

The MySqlConnection constructor takes a connection string as one of its parameters. The connection string provides necessary information to make the connection to the MariaDB database. The connection string is discussed more fully in , "Connecting to MariaDB Using Connector/Net". For a list of supported connection string options, see , "Connector/Net Connection String Options Reference".

The following code shows how to create a connection object: 

using System;
using System.Data;
using MySql.Data;
using MySql.Data.MySqlClient;
public class Tutorial1
{
 public static void Main()
 {
 string connStr = 'server=localhost;user=root;database=world;port=3306;password=******;';
 MySqlConnection conn = new MySqlConnection(connStr);
 try
 {
 Console.WriteLine('Connecting to MariaDB...');
 conn.Open();
 // Perform database operations
 }
 catch (Exception ex)
 {
 Console.WriteLine(ex.ToString());
 }
 conn.Close();
 Console.WriteLine('Done.');
 }
}

When the MySqlConnection constructor is invoked, it returns a connection object, which is used for subsequent database operations. Open the connection before any other operations take place. Before the application exits, close the connection to the database by calling Close on the connection object.

Sometimes an attempt to perform an Open on a connection object can fail, generating an exception that can be handled using standard exception handling code.

In this section you have learned how to create a connection to a MariaDB database, and open and close the corresponding connection object.

The MySqlCommand Object

Once a connection has been established with the MariaDB database, the next step is do carry out the desired database operations. This can be achieved through the use of the MySqlCommand object.

You will see how to create a MySqlCommand object. Once it has been created, there are three main methods of interest that you can call:

Once a MySqlCommand object has been created, you will call one of the above methods on it to carry out a database operation, such as perform a query. The results are usually returned into a MySqlDataReader object, and then processed, for example the results might be displayed. The following code demonstrates how this could be done. 

using System;
using System.Data;
using MySql.Data;
using MySql.Data.MySqlClient;
public class Tutorial2
{
 public static void Main()
 {
 string connStr = 'server=localhost;user=root;database=world;port=3306;password=******;';
 MySqlConnection conn = new MySqlConnection(connStr);
 try
 {
 Console.WriteLine('Connecting to MariaDB...');
 conn.Open();
 string sql = 'SELECT Name, HeadOfState FROM Country WHERE Continent="Oceania"';
 MySqlCommand cmd = new MySqlCommand(sql, conn);
 MySqlDataReader rdr = cmd.ExecuteReader();
 while (rdr.Read())
 {
 Console.WriteLine(rdr[0]+' -- '+rdr[1]);
 }
 rdr.Close();
 }
 catch (Exception ex)
 {
 Console.WriteLine(ex.ToString());
 }
 conn.Close();
 Console.WriteLine('Done.');
 }
}

When a connection has been created and opened, the code then creates a MySqlCommand object. Note that the SQL query to be executed is passed to the MySqlCommand constructor. The ExecuteReader method is then used to generate a MySqlReader object. The MySqlReader object contains the results generated by the SQL executed on the command object. Once the results have been obtained in a MySqlReader object, the results can be processed. In this case, the information is printed out by a while loop. Finally, the MySqlReader object is disposed of by running its Close method on it.

In the next example, you will see how to use the ExecuteNonQuery method.

The procedure for performing an ExecuteNonQuery method call is simpler, as there is no need to create an object to store results. This is because ExecuteNonQuery is only used for inserting, updating and deleting data. The following example illustrates a simple update to the Country table: 

using System;
using System.Data;
using MySql.Data;
using MySql.Data.MySqlClient;
public class Tutorial3
{
 public static void Main()
 {
 string connStr = 'server=localhost;user=root;database=world;port=3306;password=******;';
 MySqlConnection conn = new MySqlConnection(connStr);
 try
 {
 Console.WriteLine('Connecting to MariaDB...');
 conn.Open();
 string sql = 'INSERT INTO Country (Name, HeadOfState, Continent) VALUES ('Disneyland','Mickey Mouse', 'North America')';
 MySqlCommand cmd = new MySqlCommand(sql, conn);
 cmd.ExecuteNonQuery();
 }
 catch (Exception ex)
 {
 Console.WriteLine(ex.ToString());
 }
 conn.Close();
 Console.WriteLine('Done.');
 }
}

The query is constructed, the command object created and the ExecuteNonQuery method called on the command object. You can access your MariaDB database with the mysql command interpreter and verify that the update was carried out correctly.

Finally, you will see how the ExecuteScalar method can be used to return a single value. Again, this is straightforward, as a MySqlDataReader object is not required to store results, a simple variable will do. The following code illustrates how to use ExecuteScalar: 

using System;
using System.Data;
using MySql.Data;
using MySql.Data.MySqlClient;
public class Tutorial4
{
 public static void Main()
 {
 string connStr = 'server=localhost;user=root;database=world;port=3306;password=******;';
 MySqlConnection conn = new MySqlConnection(connStr);
 try
 {
 Console.WriteLine('Connecting to MariaDB...');
 conn.Open();
 string sql = 'SELECT COUNT(*) FROM Country';
 MySqlCommand cmd = new MySqlCommand(sql, conn);
 object result = cmd.ExecuteScalar();
 if (result != null)
 {
 int r = Convert.ToInt32(result);
 Console.WriteLine('Number of countries in the World database is: ' + r);
 }
 }
 catch (Exception ex)
 {
 Console.WriteLine(ex.ToString());
 }
 conn.Close();
 Console.WriteLine('Done.');
 }
}

This example uses a simple query to count the rows in the Country table. The result is obtained by calling ExecuteScalar on the command object.

Working with Decoupled Data

Previously, when using MySqlDataReader, the connection to the database was continually maintained, unless explicitly closed. It is also possible to work in a manner where a connection is only established when needed. For example, in this mode, a connection could be established to read a chunk of data, the data could then be modified by the application as required. A connection could then be reestablished only if and when the application writes data back to the database. This decouples the working data set from the database.

This decoupled mode of working with data is supported by Connector/Net. There are several parts involved in allowing this method to work:

Each of these classes will now be discussed in more detail.

Instantiating a DataSet object

A DataSet object can be created simply, as shown in the following example code snippet: 

DataSet dsCountry;
...
dsCountry = new DataSet();

Although this creates the DataSet object, it has not yet filled it with data. For that, a Data Adapter is required.

Instantiating a MySqlDataAdapter object

The MySqlDataAdapter can be created as illustrated by the following example: 

MySqlDataAdapter daCountry;
...
string sql = 'SELECT Code, Name, HeadOfState FROM Country WHERE Continent="North America"';
daCountry = new MySqlDataAdapter (sql, conn);

Note, the MySqlDataAdapter is given the SQL specifying the data to work with.

Instantiating a MySqlCommandBuilder object

Once the MySqlDataAdapter has been created, it is necessary to generate the additional statements required for inserting, updating and deleting data. There are several ways to do this, but in this tutorial you will see how this can most easily be done with MySqlCommandBuilder. The following code snippet illustrates how this is done: 

MySqlCommandBuilder cb = new MySqlCommandBuilder(daCountry);

Note that the MySqlDataAdapter object is passed as a parameter to the command builder.

Filling the Data Set

To do anything useful with the data from your database, you need to load it into a Data Set. This is one of the jobs of the MySqlDataAdapter object, and is carried out with its Fill method. The following example code illustrates this: 

DataSet dsCountry;
...
dsCountry = new DataSet();
...
daCountry.Fill(dsCountry, 'Country');

Note the Fill method is a MySqlDataAdapter method, the Data Adapter knows how to establish a connec tion with the database and retrieve the required data, and then populates the Data Set when the Fill method is called. The second parameter "Country" is the table in the Data Set to update.

Updating the Data Set

The data in the Data Set can now be manipulated by the application as required. At some point, changes to data will need to be written back to the database. This is achieved through a MySqlDataAdapter method, the Update method. 

daCountry.Update(dsCountry, 'Country');

Again, the Data Set and the table within the Data Set to update are specified.

Working Example

The interactions between the DataSet, MySqlDataAdapter and MySqlCommandBuilder classes can be a little confusing, so their operation can perhaps be best illustrated by working code.

In this example, data from the World database is read into a Data Grid View control. Here, the data can be viewed and changed before clicking an update button. The update button then activates code to write changes back to the database. The code uses the principles explained above. The application was built using the Microsoft Visual Studio to place and create the user interface controls, but the main code that uses the key classes described above is shown below, and is portable. 

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using MySql.Data;
using MySql.Data.MySqlClient;
namespace WindowsFormsApplication5
{
 public partial class Form1 : Form
 {
 MySqlDataAdapter daCountry;
 DataSet dsCountry;
 public Form1()
 {
 InitializeComponent();
 }
 private void Form1_Load(object sender, EventArgs e)
 {
 string connStr = 'server=localhost;user=root;database=world;port=3306;password=******;';
 MySqlConnection conn = new MySqlConnection(connStr);
 try
 {
 label2.Text = 'Connecting to MariaDB...';
 string sql = 'SELECT Code, Name, HeadOfState FROM Country WHERE Continent="North America"';
 daCountry = new MySqlDataAdapter (sql, conn);
 MySqlCommandBuilder cb = new MySqlCommandBuilder(daCountry);
 dsCountry = new DataSet();
 daCountry.Fill(dsCountry, 'Country');
 dataGridView1.DataSource = dsCountry;
 dataGridView1.DataMember = 'Country';
 }
 catch (Exception ex)
 {
 label2.Text = ex.ToString();
 }
 }
 private void button1_Click(object sender, EventArgs e)
 {
 daCountry.Update(dsCountry, 'Country');
 label2.Text = 'MySQL Database Updated!';
 }
 }
}

The application running is shown below:

Figure 20.30. World Database Application

World Database Application
Working with Parameters

This part of the tutorial shows you how to use parameters in your Connector/Net application.

Although it is possible to build SQL query strings directly from user input, this is not advisable as it does not prevent erroneous or malicious information being entered. It is safer to use parameters as they will be processed as field data only. For example, imagine the following query was constructed from user input: 

string sql = 'SELECT Name, HeadOfState FROM Country WHERE Continent = '+user_continent;

If the string user_continent came from a Text Box control, there would potentially be no control over the string entered by the user. The user could enter a string that generates a run time error, or in the worst case actually harms the system. When using parameters it is not possible to do this because a parameter is only ever treated as a field parameter, rather than an arbitrary piece of SQL code.

The same query written user a parameter for user input would be: 

string sql = 'SELECT Name, HeadOfState FROM Country WHERE Continent = @Continent';

Note that the parameter is preceded by an '@' symbol to indicate it is to be treated as a parameter.

As well as marking the position of the parameter in the query string, it is necessary to add a parameter to the Command object. This is illustrated by the following code snippet: 

cmd.Parameters.AddWithValue('@Continent', 'North America');

In this example the string 'North America' is supplied as the parameter value statically, but in a more practical example it would come from a user input control.

A further example illustrates the complete process: 

using System;
using System.Data;
using MySql.Data;
using MySql.Data.MySqlClient;
public class Tutorial5
{
 public static void Main()
 {
 string connStr = 'server=localhost;user=root;database=world;port=3306;password=******;';
 MySqlConnection conn = new MySqlConnection(connStr);
 try
 {
 Console.WriteLine('Connecting to MariaDB...');
 conn.Open();
 string sql = 'SELECT Name, HeadOfState FROM Country WHERE Continent=@Continent';
 MySqlCommand cmd = new MySqlCommand(sql, conn);
 Console.WriteLine('Enter a continent e.g. 'North America', 'Europe': ');
 string user_input = Console.ReadLine();
 cmd.Parameters.AddWithValue('@Continent', user_input);
 MySqlDataReader rdr = cmd.ExecuteReader();
 while (rdr.Read())
 {
 Console.WriteLine(rdr['Name']+' --- '+rdr['HeadOfState']);
 }
 rdr.Close();
 }
 catch (Exception ex)
 {
 Console.WriteLine(ex.ToString());
 }
 conn.Close();
 Console.WriteLine('Done.');
 }
}

In this part of the tutorial you have see how to use parameters to make your code more secure.

Working with Stored Procedures

In this section, you will see how to work with stored procedures. This section assumes you have a basic understanding of what a stored procedure is, and how to create one.

For the purposes of this tutorial, you will create a simple Stored Procedure to see how it can be called from Connector/Net. In the MariaDB Client program, connect to the World database and enter the following stored procedure: 

DELIMITER //
CREATE PROCEDURE country_hos
(IN con CHAR(20))
BEGIN
 SELECT Name, HeadOfState FROM Country
 WHERE Continent = con;
END //
DELIMITER ;

Test that the stored procedure works as expected by typing the following into the mysql command interpreter: 

CALL country_hos('Europe');

Note that The stored routine takes a single parameter, which is the continent to restrict your search to.

Having confirmed that the stored procedure is present and correct, you can see how to access it from Connector/Net.

Calling a stored procedure from your Connector/Net application is similar to techniques you have seen earlier in this tutorial. A MySqlCommand object is created, but rather than taking an SQL query as a parameter, it takes the name of the stored procedure to call. Set the MySqlCommand object to the type of stored procedure, as shown by the following code snippet: 

string rtn = 'country_hos';
MySqlCommand cmd = new MySqlCommand(rtn, conn);
cmd.CommandType = CommandType.StoredProcedure;

In this case, the stored procedure requires you to pass a parameter. This can be achieved using the techniques seen in the previous section on parameters, , "Working with Parameters", as shown in the following code snippet: 

cmd.Parameters.AddWithValue('@con', 'Europe');

The value of the parameter @con could more realistically have come from a user input control, but for simplicity it is set as a static string in this example.

At this point, everything is set up and you can call the routine using techniques also learned in earlier sections. In this case, the ExecuteReader method of the MySqlCommand object is used.

Complete working code for the stored procedure example is shown below: 

using System;
using System.Data;
using MySql.Data;
using MySql.Data.MySqlClient;
public class Tutorial6
{
 public static void Main()
 {
 string connStr = 'server=localhost;user=root;database=world;port=3306;password=******;';
 MySqlConnection conn = new MySqlConnection(connStr);
 try
 {
 Console.WriteLine('Connecting to MariaDB...');
 conn.Open();
 string rtn = 'country_hos';
 MySqlCommand cmd = new MySqlCommand(rtn, conn);
 cmd.CommandType = CommandType.StoredProcedure;
 cmd.Parameters.AddWithValue('@con', 'Europe');
 MySqlDataReader rdr = cmd.ExecuteReader();
 while (rdr.Read())
 {
 Console.WriteLine(rdr[0] + ' --- ' + rdr[1]);
 }
 rdr.Close();
 }
 catch (Exception ex)
 {
 Console.WriteLine(ex.ToString());
 }
 conn.Close();
 Console.WriteLine('Done.');
 }
}

In this section, you have seen how to call a stored procedure from Connector/Net. For the moment, this concludes our introductory tutorial on programming with Connector/Net.

Tutorial: MariaDB Connector/Net ASP.NET Membership and Role Provider

Many web sites feature the facility for the user to create a user account. They can then log into the web site and enjoy a personalized experience. This requires that the developer creates database tables to store user information, along with code to gather and process this data. This represents a burden on the developer, and there is the possibility for security issues to creep into the developed code. However, ASP.NET 2.0 introduced the Membership system. This system is designed around the concept of Membership, Profile and Role Providers, which together provide all of the functionality to implement a user system, that previously would have to have been created by the developer from scratch.

Currently, MariaDB Connector/Net provides Membership, Role, Profile and Session State Providers.

This tutorial shows you how to set up your ASP.NET web application to use the MariaDB Connector/Net Membership and Role Providers. It assumes that you have MariaDB Server installed, along with MariaDB Connector/Net and Microsoft Visual Studio. This tutorial was tested with MariaDB Connector/Net 6.0.4 and Microsoft Visual Studio 2008 Professional Edition. It is recommended you use 6.0.4 or above for this tutorial.

  1. Create a new database in the MariaDB Server using the MariaDB Command Line Client program (MariaDB), or other suitable tool. It does not matter what name is used for the database, but record it. You specify it in the connection string constructed later in this tutorial. This database contains the tables, automatically created for you later, used to store data about users and roles.
  2. Create a new ASP.NET Web Site in Visual Studio. If you are not sure how to do this, refer to , "Tutorial: Databinding in ASP.NET using LINQ on Entities", which demonstrates how to create a simple ASP.NET web site.
  3. Add References to MySql.Data and MySql.Web to the web site project.
  4. Locate the machine.config file on your system, which is the configuration file for the .NET Framework.
  5. Search the machine.config file to find the membership provider MySQLMembershipProvider.
  6. Add the attribute autogenerateschema='true'. The appropriate section should now resemble the following (note: for the sake of brevity some information has been excluded): 
    <membership>
 <providers>
 <add name="AspNetSqlMembershipProvider" 
 type="System.Web.Security.SqlMembershipProvider" 
 ... 
 connectionStringName="LocalSqlServer" 
 ... />
 <add name="MySQLMembershipProvider" 
 autogenerateschema="true" 
 type="MySql.Web.Security.MySQLMembershipProvider, MySql.Web, Version=6.0.4.0, Culture=neutral, PublicKeyToken=c5687fc88969c44d" 
 connectionStringName="LocalMySqlServer" 
 ... />
 </providers>
</membership>

    Note that the name for the connection string to be used to connect to the server that contains the membership database is LocalMySqlServer.

    The autogenerateschema='true' attribute will cause MariaDB Connector/Net to silently create, or upgrade, the schema on the database server, to contain the required tables for storing membership information.

  7. It is now necessary to create the connection string referenced in the previous step. Load the web site's web.config file into Visual Studio.
  8. Locate the section marked <connectionStrings>. Add the following connection string information: 
    <connectionStrings>
 <remove name="LocalMySqlServer"/>
 <add name="LocalMySqlServer"
 connectionString="Datasource=localhost;Database=users;uid=root;pwd=password;"
 providerName="MySql.Data.MySqlClient"/>
</connectionStrings>

    The database specified is the one created in the first step. You could alternatively have used an existing database.

  9. At this point build the solution to ensure no errors are present. This can be done by selecting Build, Build Solution from the main menu, or pressing F6.
  10. ASP.NET supports the concept of locally and remotely authenticated users. With local authentication the user is validated using their Windows credentials when they attempt to access the web site. This can be useful in an Intranet environment. With remote authentication, a user is prompted for their login details when accessing the web site, and these credentials are checked against the membership information stored in a database server such as MariaDB Server. You will now see how to choose this form of authentication.

    Start the ASP.NET Web Site Administration Tool. This can be done quickly by clicking the small hammer/Earth icon in the Solution Explorer. You can also launch this tool by selecting Website, ASP.NET Configuration from the main menu.

  11. In the ASP.NET Web Site Administration Tool click the Security tab.
  12. Now click the User Authentication Type link.
  13. Select the From the internet radio button. The web site will now need to provide a form to allow the user to enter their login details. These will be checked against membership information stored in the MariaDB database.

    Figure 20.31. Authentication Type

    Authentication Type
  14. You now need to specify the Role and Membership Provider to be used. Click the Provider tab.
  15. Click the Select a different provider for each feature (advanced) link.
  16. Now select the MySQLMembershipProvider and the MySQLRoleProvider radio buttons.

    Figure 20.32. Select Membership and Role Provider

    Select Membership and Role Provider
  17. In Visual Studio, rebuild the solution by selecting Build, Rebuild Solution from the main menu.
  18. Check that the necessary schema has been created. This can be achieved using the mysql command interpreter.

    Figure 20.33. Membership and Role Provider Tables

    Membership and Role Provider Tables
  19. Assuming all is present and correct, you can now create users and roles for your web application. The easiest way to do this is with the ASP.NET Web Site Administration Tool. However, many web applications contain their own modules for creating roles and users. For simplicity, the ASP.NET Web Site Administration Tool will be used in this tutorial.
  20. In the ASP.NET Web Site Administration Tool, click the Security tab. Now that both the Membership and Role Provider are enabled, you will see links for creating roles and users. Click the Create or Manage Roles link.

    Figure 20.34. Security Tab

    Security Tab
  21. You can now enter the name of a new Role and click Add Role to create the new Role. Create new Roles as required.
  22. Click the Back button.
  23. Click the Create User link. You can now fill in information about the user to be created, and also allocate that user to one or more Roles.

    Figure 20.35. Create User

    Create User
  24. Using the mysql command interpreter, you can check that your database has been correctly populated with the Membership and Role data.

    Figure 20.36. Membership and Roles Table Contents

    Membership and Roles Table Contents

In this tutorial, you have seen how to set up the MariaDB Connector/Net Membership and Role Providers for use in your ASP.NET web application.

Tutorial: MariaDB Connector/Net ASP.NET Session State Provider

MySQL Connector/Net from version 6.1 has included a MariaDB Session State Provider. This provider enables you to store session state in a MariaDB database. The following tutorial shows you how to prepare to use the MariaDB Session State Provider, and then store session data into the MariaDB database. This tutorial uses Microsoft Visual Studio 2008 Professional Edition, MariaDB Connector/Net 6.1.1 and MariaDB Server 5.1. This tutorial also assumes you have created an empty database, for example test, where you will store session data. You could do this using the mysql command interpreter.

  1. In Visual Studio, create a new ASP.NET web site. If you are not sure how to do this, refer to the tutorial , "Tutorial: Databinding in ASP.NET using LINQ on Entities", which demonstrates how to do this.
  2. Launch the MariaDB MySQL Website Configuration tool. Due to a bug in 6.1.1, this may not appear unless you are connected to a server in the Server Explorer. If you are unfamiliar with the MariaDB Website Configuration tool, consider first working through the tutorial in , "MySQL Website Configuration Tool".
  3. Navigate through the wizard to the Session State page. Make sure the check box Use MariaDB to manage my ASP.NET session data is selected.
  4. On the same page, configure the connection string to the database that will contain your session data. If this database is empty, MariaDB Connector/Net will create the schema required to store session data.
  5. Ensure that the check box Autogenerate Schema is selected so that MariaDB Connector/Net will create the schema in your database to store the session data correctly.
  6. Enter the name of your application.
  7. Click Finish. The MariaDB Website Configuration tool will now update your application's web.config file with information about the connection string and default providers to be used. In this case, we have selected the MariaDB Session State Provider.

At this point, you are ready to use the MariaDB database to store session data. To test that the set up has worked, you can write a simple program that uses session variables.

  1. Open Default.aspx.cs. In the Page_Load method, add the following code: 

    Session['SessionVariable1'] = 'Test string';
  2. Build your solution.
  3. Run the solution (without debugging). When the application runs, the provider will autogenerate tables required in the database you chose when setting up the application.
  4. Check that the schema was in fact created. Using the MariaDB Command Line Client use the target database and then type SHOW TABLES;. You will see that MariaDB Connector/Net has created the required schema automatically, as we selected this to happen in the MariaDB Website Configuration tool.
  5. Now view the contents of these tables by typing SELECT * FROM my_aspnet_sessions; in the mysql command interpreter. This will display the session data our application used. Note that this is stored in binary format so some data may not display as expected.

At this point, you have installed the Session State Provider and carried out a preliminary test of the installation. You will now work a bit more with the Session State Provider.

In this part of the tutorial, you will set and retrieve a session variable. You can work with your existing project.

  1. Select the Default.aspx and switch to Design View. Add a text box and three buttons. Change the text property for the buttons to "Store Session Variable", "Clear Textbox", and "Show Session Variable". These will be Button1, Button2 and Button3 respectively. Build your solution to ensure that no errors have been introduced.
  2. Still in the Design View, double-click Button1. Now to the Button1_Click event handler add code some the handler resembles the following: 
    protected void Button1_Click(object sender, EventArgs e)
{
 Session['SessionString'] = TextBox1.Text;
}

    You have created a new Session variable accessed using the key "SessionString". This will be set to the text that was entered into the text box when Button1 is clicked.

  3. In Design View, double-click Button2 to add its click event handler. This button needs to clear text from the text box. The code to do this is as follows: 
    protected void Button2_Click(object sender, EventArgs e)
{
 TextBox1.Text = '';
}

    The code simply assigns an empty string to the Text property of the text box.

  4. In the Design View double-click Button3 and modify the click handler as follows: 
    protected void Button3_Click(object sender, EventArgs e)
{
 TextBox1.Text = (String)Session['SessionString'];
}

    This will retrieve the session string and display it in the text box.

  5. Now modify the Page_Load method as follows: 
    protected void Page_Load(object sender, EventArgs e)
{
 if (!IsPostBack)
 {
 TextBox1.Text = 'Enter some text'; 
 }
}

    This ensures that when the page loads the text box Text property is reset.

  6. Ensure that the solution is saved and then rebuild the solution.
  7. Run the solution without debugging.
  8. The form will be displayed. Enter some text into the text box. Now click Store Session Variable. At this point you have stored the string in a session variable.
  9. Now click Clear Text to clear the text box.
  10. Now click Show Session Variable to retrieve and display the session variable.
  11. Refresh the page to destroy the form and display a new form.
  12. Click Show Session Variable the text box will display the stored session variable, demonstrating that the refreshing the page does not destroy the session variable.

This illustrates that the session state data is not destroyed when a page is reloaded.

Tutorial: MariaDB Connector/Net ASP.NET Profile Provider

This tutorial shows you how to use the MariaDB Profile Provider to store user profile information in a MariaDB database. The tutorial uses MariaDB Connector/Net 6.1.1, MariaDB Server 5.1 and Microsoft Visual Studio 2008 Professional Edition.

Many modern web sites allow the user to create a personal profile. This requires a significant amount of code, but ASP.NET reduces this considerable by including the functionality in its Profile classes. The Profile Provider provides an abstraction between these classes and a data source. The MariaDB Profile Provider enables profile data to be stored in a MariaDB database. This enables the profile properties to be written to a persistent store, and be retrieved when required. The Profile Provider also enables profile data to be managed effectively, for example it enables profiles that have not been accessed since a specific date to be deleted.

The following steps show you how you can select the MariaDB Profile Provider.

  1. Create a new ASP.NET web project.
  2. Select the MariaDB Website Configuration tool. Due to a bug in 6.1.1 you may have to first connect to a server in Server Explorer before the tool's icon will display in the toolbar of the Solution Explorer.
  3. In the MariaDB Website Configuration tool navigate through the tool to the Profiles page.
  4. Select the Use MariaDB to manage my profiles check box.
  5. Select the Autogenerate Schema check box.
  6. Click the Edit... button and configure a connection string for the database that will be used to store user profile information.
  7. Navigate to the last page of the tool and click Finish to save your changes and exit the tool.

At this point you are now ready to start using the MariaDB Profile Provider. With the following steps you can carry out a preliminary test of your installation.

  1. Open your web.config file.
  2. Add a simple profile such as the following: 
    <system.web>
 <anonymousIdentification enabled="true"/> 
 <profile defaultProvider="MySQLProfileProvider">
 ...
 <properties>
 <add name="Name" allowAnonymous="true"/>
 <add name="Age" allowAnonymous="true" type="System.UInt16"/>
 <group name="UI">
 <add name="Color" allowAnonymous="true" defaultValue="Blue"/>
 <add name="Style" allowAnonymous="true" defaultValue="Plain"/>
 </group>
 </properties>
 </profile>
 ...

    Note that anonymousIdentification has been set to true. This enables users who have not been authenticated to use profiles. They are identified by a GUID in a cookie rather than by user name.

Now that the simple profile has been defined in web.config, the next step is to write some code to test the profile.

  1. In Design View design a simple page with the following controls:

    Figure 20.37. Simple Profile Application

    Simple Profile Application

    These will allow the user to enter some profile information. The user can also use the buttons to save their profile, clear the page, and restore their profile data.

  2. In the Code View add code as follows: 
    ...
protected void Page_Load(object sender, EventArgs e)
{
 if (!IsPostBack)
 {
 TextBox1.Text = Profile.Name;
 TextBox2.Text = Profile.Age.ToString();
 Label1.Text = Profile.UI.Color;
 }
}
// Store Profile protected void Button1_Click(object sender, EventArgs e)
{
 Profile.Name = TextBox1.Text;
 Profile.Age = UInt16.Parse(TextBox2.Text);
}
// Clear Form protected void Button2_Click(object sender, EventArgs e)
{
 TextBox1.Text = '';
 TextBox2.Text = '';
 Label1.Text = '';
}
// Retrieve Profile protected void Button3_Click(object sender, EventArgs e)
{
 TextBox1.Text = Profile.Name;
 TextBox2.Text = Profile.Age.ToString();
 Label1.Text = Profile.UI.Color;
}
protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e)
{
 Profile.UI.Color = DropDownList1.SelectedValue;
}
...
  3. Save all files and build the solution to check that no errors have been introduced.
  4. Run the application.
  5. Enter your name, age and select a color from the listbox. Now store this information in your profile by clicking Store Profile. Note that if you do not select a color from the listbox your profile will use the default color Blue that was specified in the web.config file.
  6. Click Clear Form to clear text from the textboxes and the label that displays your chosen color.
  7. Now click Retrieve Profile to restore your profile data from the MariaDB database.
  8. Now exit the browser to terminate the application.
  9. Run the application again. Note that when the page loads your profile information is restored from the MariaDB database.

In this tutorial you have seen how to using the MariaDB Profile Provider with MariaDB Connector/Net.

Tutorial: Using an Entity Framework Entity as a Windows Forms Data Source

In this tutorial you will learn how to create a Windows Forms Data Source from an Entity in an Entity Data Model. This tutorial assumes that you have installed the World example database, which can be downloaded from the MySQL Documentation page. You can also find details on how to install the database on the same page. It will also be convenient for you to create a connection to the World database after it is installed. For instructions on how to do this see , "Making a Connection".

Creating a new Windows Forms application

The first step is to create a new Windows Forms application.

  1. In Visual Studio, select File, New, Project from the main menu.
  2. Choose the Windows Forms Application installed template. Click OK. The solution is created.

Adding an Entity Data Model

You will now add an Entity Data Model to your solution.

  1. In the Solution Explorer, right-click your application and select Add, New Item.... From Visual Studio installed templates select ADO.NET Entity Data Model. Click Add.

    Figure 20.38. Add Entity Data Model

    Add Entity Data Model
  2. You will now see the Entity Data Model Wizard. You will use the wizard to generate the Entity Data Model from the world example database. Select the icon Generate from database. Click Next.

    Figure 20.39. Entity Data Model Wizard Screen 1

    Entity Data Model Wizard Screen 1
  3. You can now select the connection you made earlier to the World database. If you have not already done so, you can create the new connection at this time by clicking New Connection.... For further instructions on creating a connection to a database see , "Making a Connection".

    Figure 20.40. Entity Data Model Wizard Screen 2

    Entity Data Model Wizard Screen 2
  4. Make a note of the entity connection settings to be used in App.Config, as these will be used later to write the necessary control code.
  5. Click Next.
  6. The Entity Data Model Wizard connects to the database. You are then presented with a tree structure of the database. From this you can select the object you would like to include in your model. If you had created Views and Stored Routines these will be displayed along with any tables. In this example you just need to select the tables. Click Finish to create the model and exit the wizard.

    Figure 20.41. Entity Data Model Wizard Screen 3

    Entity Data Model Wizard Screen 3
  7. Visual Studio will generate the model and then display it.

    Figure 20.42. Entity Data Model Diagram

    Entity Data Model Diagram
  8. From the Visual Studio main menu select Build, Build Solution, to ensure that everything compiles correctly so far.

Adding a new Data Source

You will now add a new Data Source to your project and see how it can be used to read and write to the database.

  1. From the Visual Studio main menu select Data, Add New Data Source.... You will be presented with the Data Source Configuration Wizard.

    Figure 20.43. Entity Data Source Configuration Wizard Screen 1

    Entity Data Source Configuration Wizard Screen 1
  2. Select the Object icon. Click Next.
  3. You will now select the Object to bind to. Expand the tree. In this tutorial, you will select the city table. Once the city table has been selected click Next.

    Figure 20.44. Entity Data Source Configuration Wizard Screen 2

    Entity Data Source Configuration Wizard Screen 2
  4. The wizard will confirm that the city object is to be added. Click Finish.

    Figure 20.45. Entity Data Source Configuration Wizard Screen 3

    Entity Data Source Configuration Wizard Screen 3
  5. The city object will be display in the Data Sources panel. If the Data Sources panel is not displayed, select Data, Show Data Sources from the Visual Studio main menu. The docked panel will then be displayed.

    Figure 20.46. Data Sources

    Data Sources

Using the Data Source in a Windows Form

You will now learn how to use the Data Source in a Windows Form.

  1. In the Data Sources panel select the Data Source you just created and drag and drop it onto the Form Designer. By default the Data Source object will be added as a Data Grid View control. Note that the Data Grid View control is bound to the cityBindingSource and the Navigator control is bound to cityBindingNavigator.

    Figure 20.47. Data Form Designer

    Data Form Designer
  2. Save and rebuild the solution before continuing.

Adding Code to Populate the Data Grid View

You are now ready to add code to ensure that the Data Grid View control will be populated with data from the City database table.

  1. Double-click the form to access its code.
  2. Add code to instatiate the Entity Data Model's EntityContainer object and retrieve data from the database to populate the control.

    Figure 20.48. Adding Code to the Form

    Adding Code to the Form
  3. Save and rebuild the solution.
  4. Run the solution. Ensure the grid is populated and you can navigate the database.

    Figure 20.49. The Populated Grid Control

    The Populated Grid Control

Adding Code to Save Changes to the Database

You will now add code to enable you to save changes to the database.

The Binding source component ensures that changes made in the Data Grid View control are also made to the Entity classes bound to it. However, that data needs to be saved back from the entities to the database itself. This can be achieved by the enabling of the Save button in the Navigator control, and the addition of some code.

  1. In the Form Designer, click the Save icon in the Form toolbar and ensure that its Enabled property is set to True.

    Figure 20.50. Save Button Enabled

    Save Button Enabled
  2. Double-click the Save icon in the Form toolbar to display its code.
  3. You now need to add code to ensure that data is saved to the database when the save button is clicked in the application.

    Figure 20.51. Adding Save Code to the Form

    Adding Save Code to the Form
  4. Once the code has been added, save the solution and rebuild it. Run the application and verify that changes made in the grid are saved.

Tutorial: Databinding in ASP.NET using LINQ on Entities

In this tutorial you create an ASP.NET web page that binds LINQ queries to entities using the Entity Framework mapping.

If you have not already done so, install the World example database prior to attempting this tutorial. See the tutorial , "Tutorial: Using an Entity Framework Entity as a Windows Forms Data Source" for instructions on downloading and installing this database.

Creating an ASP.NET web site

In this part of the tutorial, you will create an ASP.NET web site. The web site will use the World database. The main web page will feature a drop down list from which you can select a country, data about that country's cities will then be displayed in a grid view control.

  1. From the Visual Studio main menu select File, New, Web Site....
  2. From the Visual Studio installed templates select ASP.NET Web Site. Click OK. You will be presented with the Source view of your web page by default.
  3. Click the Design view tab situated underneath the Source view panel.

    Figure 20.52. The Design Tab

    The Design Tab
  4. In the Design view panel, enter some text to decorate the blank web page.
  5. Click Toolbox. From the list of controls select DropDownList. Drag and drop the control to a location beneath the text on your web page.

    Figure 20.53. Drop Down List

    Drop Down List
  6. From the DropDownList control's context menu, ensure that the Enable AutoPostBack check box is enabled. This will ensure the control's event handler is called when an item is selected. The user's choice will in turn be used to populate the GridView control.

    Figure 20.54. Enable AutoPostBack

    Enable AutoPostBack
  7. From the Toolbox select the GridView control.

    Figure 20.55. Grid View Control

    Grid Vew Control

    Drag and drop the Grid Vew control to a location just below the Drop Down List you already placed.

    Figure 20.56. Placed Grid Vew Control

    Placed Grid View Control
  8. At this point it is recommended that you save your solution, and build the solution to ensure that there are no errors.
  9. If you run the solution you will see that the text and drop down list are displayed, but the list is empty. Also, the grid view does not appear at all. Adding this functionality is described in the following sections.

At this stage you have a web site that will build, but further functionality is required. The next step will be to use the Entity Framework to create a mapping from the World database into entities that you can control programmatically.

Creating an ADO.NET Entity Data Model

In this stage of the tutorial you will add an ADO.NET Entity Data Model to your project, using the World database at the storage level. The procedure for doing this is described in the tutorial , "Tutorial: Using an Entity Framework Entity as a Windows Forms Data Source", and so will not be repeated here.

Populating a Drop Data List Box with using the results of a entity LINQ query

In this part of the tutorial you will write code to populate the DropDownList control. When the web page loads the data to populate the list will be achieved by using the results of a LINQ query on the model created previously.

  1. In the Design view panel, double-click any blank area. This brings up the Page_Load method.
  2. Modify the relevant section of code according to the following listing: 
    ...
public partial class _Default : System.Web.UI.Page
{
 worldModel.worldEntities we;
 protected void Page_Load(object sender, EventArgs e)
 {
 we = new worldModel.worldEntities();
 if (!IsPostBack)
 {
 var countryQuery = from c in we.country
 orderby c.Name
 select new { c.Code, c.Name };
 DropDownList1.DataValueField = 'Code';
 DropDownList1.DataTextField = 'Name';
 DropDownList1.DataSource = countryQuery;
 DataBind();
 }
 }
...

    Note that the list control only needs to be populated when the page first loads. The conditional code ensures that if the page is subsequently reloaded, the list control is not repopulated, which would cause the user selection to be lost.

  3. Save the solution, build it and run it. You should see the list control has been populated. You can select an item, but as yet the grid view control does not appear.

At this point you have a working Drop Down List control, populated by a LINQ query on your entity data model.

Populating a Grid View control using an entity LINQ query

In the last part of this tutorial you will populate the Grid View Control using a LINQ query on your entity data model.

  1. In the Design view, double-click the DropDownList control. This causes its SelectedIndexChanged code to be displayed. This method is called when a user selects an item in the list control and thus fires an AutoPostBack event.
  2. Modify the relevant section of code accordingly to the following listing: 
    ...
 protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e)
 {
 var cityQuery = from c in we.city
 where c.CountryCode == DropDownList1.SelectedValue
 orderby c.Name
 select new { c.Name, c.Population, c.CountryCode };
 GridView1.DataSource = cityQuery;
 DataBind();
 }
...

    The grid view control is populated from the result of the LINQ query on the entity data model.

  3. As a check compare your code to that shown in the following screenshot:

    Figure 20.57. Source Code

    Source Code
  4. Save, build and run the solution. As you select a country you will see its cities are displayed in the grid view control.

    Figure 20.58. The Working Web Site

    The Working Web Site

In this tutorial you have seen how to create an ASP.NET web site, you have also seen how you can access a MariaDB database using LINQ queries on an entity data model.

Tutorial: Using SSL with MariaDB Connector/Net

In this tutorial you will learn how you can use MariaDB Connector/Net to connect to a MariaDB server configured to use SSL. Support for SSL client certificates was added with MariaDB Connector/Net 6.2.

MySQL Server uses the PEM format for certificates and private keys. This tutorial will use the test certificates from the server test suite by way of example. You can obtain the MariaDB Server source code from MySQL Downloads. The certificates can be found in the directory ./mysql-test/std_data.

To carry out the steps in this tutorial, you must have Open SSL installed. This can be downloaded for Microsoft Windows at no charge from Shining Light Productions.

Further details on the connection string options used in this tutorial can be found at , "Connector/Net Connection String Options Reference".

Configuring the MariaDB Server to use SSL

  1. In the MariaDB Server configuration file, set the SSL parameters as follows: 

    ssl-ca=path/to/repo/mysql-test/std_data/cacert.pem 
ssl-cert=path/to/repo/mysql-test/std_data/server-cert.pem 
ssl-key=path/to/repo/mysql-test/std_data/server-key.pem

    Adjust the directories according to the location in which you installed the MariaDB source code.

  2. In this step you create a test user and set the user to require SSL.

    Using the MariaDB Command Line Client, connect as root and create the user sslclient.

  3. To set privileges and requirements, issue the following command: 
    GRANT ALL PRIVILEGES ON *.* TO sslclient@'%' REQUIRE SSL;

Creating a certificate file to use with the .NET client

  1. The .NET client does not use the PEM file format, as .NET does not support this format natively. You will be using test client certificates from the same server repository, for the purposes of this example. Convert these to PFX format first. This format is also known as PKCS#12. An article describing this procedure can be found at the Citrix website. From the directory server-repository-root/mysql-test/std_data, issue the following command: 

    openssl pkcs12 -export -in client-cert.pem -inkey client-key.pem -certfile cacert.pem -out client.pfx
  2. When asked for an export password, enter the password "pass". The file client.pfx will be generated. This file is used in the remainder of the tutorial.

Connecting to the server using a file-based certificate

  1. You will use PFX file, client.pfx you created in the previous step to authenticate the client. The following example demonstrates how to connect using the SSL Mode, CertificateFile and CertificatePassword connection string options: 

    using (MySqlConnection connection = new MySqlConnection( 
 'database=test;user=sslclient;' + 
 'CertificateFile=H:\\bzr\\mysql-trunk\\mysqlest\\std_data\\client.pfx' + 
 'CertificatePassword=pass;' + 
 'SSL Mode=Required ')) 
{ 
 connection.Open(); 
}

    The path to the certificate file will need to be changed to reflect your individual installation.

Connecting to the server using a store-based certificate

  1. The first step is to import the PFX file, client.pfx, into the Personal Store. Double-click the file in Windows explorer. This launches the Certificate Import Wizard.
  2. Follow the steps dictated by the wizard, and when prompted for the password for the PFX file, enter "pass".
  3. Click Finish to close the wizard and import the certificate into the personal store.

Examine certificates in the Personal Store

  1. Start the Microsoft Management Console by entering mmc.exe at a command prompt.
  2. Select File, Add/Remove snap-in. Click Add. Select Certificates from the list of available snap-ins in the dialog.
  3. Click Add button in the dialog, and select the My user account radio button. This is used for personal certificates.
  4. Click the Finish button.
  5. Click OK to close the Add/Remove Snap-in dialog.
  6. You will now have Certificates - Current User displayed in the left panel of the Microsoft Management Console. Expand the Certificates - Current User tree item and select Personal, Certificates. The right-hand panel will display a certificate issued to MariaDB. This is the certificate that was previously imported. Double-click the certificate to display its details.
  7. After you have imported the certificate to the Personal Store, you can use a more succint connection string to connect to the database, as illustrated by the following code: 
    using (MySqlConnection connection = new MySqlConnection( 
 'database=test;user=sslclient;' + 
 'Certificate Store Location=CurrentUser;' + 
 'SSL Mode=Required')) 
{ 
 connection.Open(); 
}

Certificate Thumbprint Parameter

If you have a large number of certificates in your store, and many have the same Issuer, this can be a source of confusion and result in the wrong certificate being used. To alleviate this situation, there is an optional Certificate Thumbprint parameter that can additionally be specified as part of the connection string. As mentioned before, you can double-click a certificate in the Microsoft Management Console to display the certificate's details. When the Certificate dialog is displayed click the Details tab and scroll down to see the thumbprint. The thumbprint will typically be a number such as ‎47 94 36 00 9a 40 f3 01 7a 14 5c f8 47 9e 76 94 d7 aa de f0. This thumbprint can be used in the connection string, as the following code illustrates: 

using (MySqlConnection connection = new MySqlConnection( 
 'database=test;user=sslclient;' + 
 'Certificate Store Location=CurrentUser;' + 
 'Certificate Thumbprint=479436009a40f3017a145cf8479e7694d7aadef0;'+ 
 'SSL Mode=Required')) 
{ 
 connection.Open(); 
}

Spaces in the thumbprint parameter are optional and the value is case-insensitive.

Tutorial: Using MySqlScript

Using Delimiters with MySqlScript

This tutorial teaches you how to use the MySqlScript class. This class enables you to execute a series of statements. Depending on the circumstances, this can be more convenient than using the MySqlCommand approach.

Further details of the MySqlScript class can be found in the reference documentation supplied with MariaDB Connector/Net.

To run the example programs in this tutorial, set up a simple test database and table using the mysql Command Line Client or MariaDB Workbench. Commands for the mysql Command Line Client are given here:

  1. CREATE DATABASE TestDB;
  2. USE TestDB;
  3. CREATE TABLE TestTable (id INT NOT NULL PRIMARY KEY AUTO_INCREMENT, name VARCHAR(100));

The main method of the MySqlScript class is the Execute method. This method causes the script (sequence of statements) assigned to the Query property of the MySqlScript object to be executed. Note the Query property can be set through the MySqlScript constructor or using the Query property. Execute returns the number of statements executed.

The MySqlScript object will execute the specified script on the connection set using the Connection property. Again, this property can be set directly or through the MySqlScript constructor. The following code snippets illustrate this: 

string sql = 'SELECT * FROM TestTable';
...
MySqlScript script = new MySqlScript(conn, sql);
...
MySqlScript script = new MySqlScript();
script.Query = sql;
script.Connection = conn;
...
script.Execute();

The MySqlScript class has several events associated with it. There are:

  1. Error - generated if an error occurs.
  2. ScriptCompleted - generated when the script successfully completes execution.
  3. StatementExecuted - generated after each statement is executed.

It is possible to assign event handlers to each of these events. These user-provided routines are called back when the connected event occurs. The following code shows how the event handlers are set up. 

script.Error += new MySqlScriptErrorEventHandler(script_Error);
script.ScriptCompleted += new EventHandler(script_ScriptCompleted);
script.StatementExecuted += new MySqlStatementExecutedEventHandler(script_StatementExecuted);

In VisualStudio, you can save typing by using tab completion to fill out stub routines. Start by typing, for example, "script.Error +=". Then press TAB, and then press TAB again. The assignment is completed, and a stub event handler created. A complete working example is shown below: 

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Data;
using MySql.Data;
using MySql.Data.MySqlClient;
namespace MySqlScriptTest
{
 class Program
 {
 static void Main(string[] args)
 {
 string connStr = 'server=localhost;user=root;database=TestDB;port=3306;password=******;';
 MySqlConnection conn = new MySqlConnection(connStr);
 try
 {
 Console.WriteLine('Connecting to MariaDB...');
 conn.Open();
 string sql = 'INSERT INTO TestTable(name) VALUES ('Superman');' +
 'INSERT INTO TestTable(name) VALUES ('Batman');' +
 'INSERT INTO TestTable(name) VALUES ('Wolverine');' +
 'INSERT INTO TestTable(name) VALUES ('Storm');';
 MySqlScript script = new MySqlScript(conn, sql);
 script.Error += new MySqlScriptErrorEventHandler(script_Error);
 script.ScriptCompleted += new EventHandler(script_ScriptCompleted);
 script.StatementExecuted += new MySqlStatementExecutedEventHandler(script_StatementExecuted);
 int count = script.Execute();
 Console.WriteLine('Executed ' + count + ' statement(s).');
 Console.WriteLine('Delimiter: ' + script.Delimiter);
 }
 catch (Exception ex)
 {
 Console.WriteLine(ex.ToString());
 }
 conn.Close();
 Console.WriteLine('Done.');
 }
 static void script_StatementExecuted(object sender, MySqlScriptEventArgs args)
 {
 Console.WriteLine('script_StatementExecuted'); 
 }
 static void script_ScriptCompleted(object sender, EventArgs e)
 {
 /// EventArgs e will be EventArgs.Empty for this method 
 Console.WriteLine('script_ScriptCompleted!');
 }
 static void script_Error(Object sender, MySqlScriptErrorEventArgs args)
 {
 Console.WriteLine('script_Error: ' + args.Exception.ToString());
 }
 }
}

Note that in the script_ScriptCompleted event handler, the EventArgs parameter e will be EventArgs.Empty. In the case of the ScriptCompleted event there is no additional data to be obtained, which is why the event object is EventArgs.Empty.

Using Delimiters with MySqlScript

Depending on the nature of the script, you may need control of the delimiter used to separate the statements that will make up a script. The most common example of this is where you have a multi-statement stored routine as part of your script. In this case if the default delimiter of ";" is used you will get an error when you attempt to execute the script. For example, consider the following stored routine: 

CREATE PROCEDURE test_routine() 
BEGIN 
 SELECT name FROM TestTable ORDER BY name;
 SELECT COUNT(name) FROM TestTable;
END

This routine actually needs to be executed on the MariaDB Server as a single statement. However, with the default delimiter of ";", the MySqlScript class would interpret the above as two statements, the first being: 

CREATE PROCEDURE test_routine() 
BEGIN 
 SELECT name FROM TestTable ORDER BY name;

Executing this as a statement would generate an error. To solve this problem MySqlScript supports the ability to set a different delimiter. This is achieved through the Delimiter property. For example, you could set the delimiter to "??", in which case the above stored routine would no longer generate an error when executed. Multiple statements can be delimited in the script, so for example, you could have a three statement script such as: 

string sql = 'DROP PROCEDURE IF EXISTS test_routine??' +
 'CREATE PROCEDURE test_routine() ' + 
 'BEGIN ' + 
 'SELECT name FROM TestTable ORDER BY name;' + 
 'SELECT COUNT(name) FROM TestTable;' +
 'END??' +
 'CALL test_routine()';

You can change the delimiter back at any point by setting the Delimiter property. The following code shows a complete working example: 

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using MySql.Data;
using MySql.Data.MySqlClient;
namespace ConsoleApplication8
{
 class Program
 {
 static void Main(string[] args)
 {
 string connStr = 'server=localhost;user=root;database=TestDB;port=3306;password=******;';
 MySqlConnection conn = new MySqlConnection(connStr);
 try
 {
 Console.WriteLine('Connecting to MariaDB...');
 conn.Open();
 string sql = 'DROP PROCEDURE IF EXISTS test_routine??' +
 'CREATE PROCEDURE test_routine() ' + 
 'BEGIN ' + 
 'SELECT name FROM TestTable ORDER BY name;' + 
 'SELECT COUNT(name) FROM TestTable;' +
 'END??' +
 'CALL test_routine()';
 MySqlScript script = new MySqlScript(conn);
 script.Query = sql;
 script.Delimiter = '??';
 int count = script.Execute();
 Console.WriteLine('Executed ' + count + ' statement(s)');
 script.Delimiter = ';';
 Console.WriteLine('Delimiter: ' + script.Delimiter);
 Console.WriteLine('Query: ' + script.Query);
 }
 catch (Exception ex)
 {
 Console.WriteLine(ex.ToString());
 }
 conn.Close();
 Console.WriteLine('Done.');
 }
 }
}

Tutorial: Generating MariaDB DDL from an Entity Framework Model

In this tutorial, you will learn how to create MariaDB DDL from an Entity Framework model. Use Visual Studio 2010 and MariaDB Connector/Net 6.3 to carry out this tutorial.

  1. Create a new console application in Visual Studio 2010.
  2. Using the Solution Explorer, add a reference to MySql.Data.Entity.
  3. From the Solution Explorer select Add, New Item. In the Add New Item dialog select Online Templates. Select ADO.NET Entity Data Model and click Add. The Entity Data Model dialog will be displayed.
  4. In the Entity Data Model dialog select Empty Model. Click Finish. A blank model will be created.
  5. Create a simple model. A single Entity will do for the purposes of this tutorial.
  6. In the Properties panel select ConceptualEntityModel from the drop-down listbox.
  7. In the Properties panel, locate the DDL Generation Template in the category Database Script Generation.
  8. For the DDL Generation property select SSDLToMySQL.tt(VS) from the drop-down listbox.
  9. Save the solution.
  10. Right-click an empty space in the model design area. The context-sensitive menu will be displayed.
  11. From the context-sensitive menu select Generate Database from Model. The Generate Database Wizard dialog will be displayed.
  12. In the Generate Database Wizard dialog select an existing connection, or create a new connection to a server. Select an appropriate radio button to show or hide sensitive data. For the purposes of this tutorial you can select Yes (although you might skip this for commercial applications).
  13. Click Next. MariaDB compatible DDL code will be generated. Click Finish to exit the wizard.

You have seen how to create MariaDB DDL code from an Entity Framework model.

Connector/Net Programming

Connecting to MariaDB Using Connector/Net
Creating a Connector/Net Connection String
Using MySqlCommand
Using Connector/Net with Connection Pooling
Using the Windows Native Authentication Plugin
Using Connector/Net with Table Caching
Using the Connector/Net with Prepared Statements
Accessing Stored Procedures with Connector/Net
Handling BLOB Data With Connector/Net
Using the Connector/Net Interceptor Classes
Handling Date and Time Information in Connector/Net
Using the MySqlBulkLoader Class
Using the MariaDB Connector/Net Trace Source Object
Binary/Nonbinary Issues
Character Set Considerations for Connector/Net
Using Connector/Net with Crystal Reports
ASP.NET Provider Model
Working with Partial Trust

Connector/Net comprises several classes that are used to connect to the database, execute queries and statements, and manage query results.

The following are the major classes of Connector/Net:

In the following sections, you will learn about some common use cases for Connector/Net, including BLOB handling, date handling, and using Connector/Net with common tools such as Crystal Reports.

Connecting to MariaDB Using Connector/Net

Introduction

All interaction between a .NET application and the MariaDB server is routed through a MySqlConnection object. Before your application can interact with the server, a MySqlConnection object must be instantiated, configured, and opened.

Even when using the MySqlHelper class, a MySqlConnection object is created by the helper class.

In this section, we will describe how to connect to MariaDB using the MySqlConnection object.

Creating a Connector/Net Connection String

Opening a Connection
Handling Connection Errors
Using GetSchema on a Connection

The MySqlConnection object is configured using a connection string. A connection string contains several key/value pairs, separated by semicolons. Each key/value pair is joined with an equal sign.

The following is a sample connection string: 

Server=127.0.0.1;Uid=root;Pwd=12345;Database=test;

In this example, the MySqlConnection object is configured to connect to a MariaDB server at 127.0.0.1, with a user name of root and a password of 12345. The default database for all statements will be the test database. All other options may be found here: , "Connector/Net Connection String Options Reference".Note

Using the '@' symbol for parameters is now the preferred approach although the old pattern of using '?' is still supported.

Please be aware however that using '@' can cause conflicts when user variables are also used. To help with this situation please see the documentation on the Allow User Variables connection string option, which can be found here: , "Connector/Net Connection String Options Reference". The Old Syntax connection string option has now been deprecated.

Opening a Connection

Once you have created a connection string it can be used to open a connection to the MariaDB server.

The following code is used to create a MySqlConnection object, assign the connection string, and open the connection.

Connector/NET can also connect using the native Windows authentication plugin. See , "Using the Windows Native Authentication Plugin" for further information.

Visual Basic Example
Dim conn As New MySql.Data.MySqlClient.MySqlConnection Dim myConnectionString as String myConnectionString = 'server=127.0.0.1;' _
 & 'uid=root;' _
 & 'pwd=12345;' _
 & 'database=test;'
Try
 conn.ConnectionString = myConnectionString
 conn.Open()
Catch ex As MySql.Data.MySqlClient.MySqlException
 MessageBox.Show(ex.Message)
End Try
C# Example
MySql.Data.MySqlClient.MySqlConnection conn;
string myConnectionString;
myConnectionString = 'server=127.0.0.1;uid=root;' +
 'pwd=12345;database=test;';
try
{
 conn = new MySql.Data.MySqlClient.MySqlConnection();
 conn.ConnectionString = myConnectionString;
 conn.Open();
}
catch (MySql.Data.MySqlClient.MySqlException ex)
{
 MessageBox.Show(ex.Message);
}

You can also pass the connection string to the constructor of the MySqlConnection class:

Visual Basic Example
Dim myConnectionString as String myConnectionString = 'server=127.0.0.1;' _
 & 'uid=root;' _
 & 'pwd=12345;' _
 & 'database=test;'
Try
 Dim conn As New MySql.Data.MySqlClient.MySqlConnection(myConnectionString)
 conn.Open()
Catch ex As MySql.Data.MySqlClient.MySqlException
 MessageBox.Show(ex.Message)
End Try
C# Example
MySql.Data.MySqlClient.MySqlConnection conn;
string myConnectionString;
myConnectionString = 'server=127.0.0.1;uid=root;' +
 'pwd=12345;database=test;';
try
{
 conn = new MySql.Data.MySqlClient.MySqlConnection(myConnectionString);
 conn.Open();
}
catch (MySql.Data.MySqlClient.MySqlException ex)
{
 MessageBox.Show(ex.Message);
}

Once the connection is open it can be used by the other Connector/Net classes to communicate with the MariaDB server.

Handling Connection Errors

Because connecting to an external server is unpredictable, it is important to add error handling to your .NET application. When there is an error connecting, the MySqlConnection class will return a MySqlException object. This object has two properties that are of interest when handling errors:

When handling errors, you can your application's response based on the error number. The two most common error numbers when connecting are as follows:

The following code shows how to adapt the application's response based on the actual error:

Visual Basic Example
Dim myConnectionString as String myConnectionString = 'server=127.0.0.1;' _
 & 'uid=root;' _
 & 'pwd=12345;' _
 & 'database=test;'
Try
 Dim conn As New MySql.Data.MySqlClient.MySqlConnection(myConnectionString)
 conn.Open()
Catch ex As MySql.Data.MySqlClient.MySqlException
 Select Case ex.Number
 Case 0
 MessageBox.Show('Cannot connect to server. Contact administrator')
 Case 1045
 MessageBox.Show('Invalid username/password, please try again')
 End Select End Try
C# Example
MySql.Data.MySqlClient.MySqlConnection conn;
string myConnectionString;
myConnectionString = 'server=127.0.0.1;uid=root;' +
 'pwd=12345;database=test;';
try
{
 conn = new MySql.Data.MySqlClient.MySqlConnection(myConnectionString);
 conn.Open();
}
 catch (MySql.Data.MySqlClient.MySqlException ex)
{
 switch (ex.Number)
 {
 case 0:
 MessageBox.Show('Cannot connect to server. Contact administrator');
 case 1045:
 MessageBox.Show('Invalid username/password, please try again');
 }
}
Important

Note that if you are using multilanguage databases you must specify the character set in the connection string. If you do not specify the character set, the connection defaults to the latin1 charset. You can specify the character set as part of the connection string, for example: 

MySqlConnection myConnection = new MySqlConnection('server=127.0.0.1;uid=root;' +
 'pwd=12345;database=test;Charset=latin1;');
Using GetSchema on a Connection
Collections

The GetSchema() method of the connection object can be used to retrieve schema information about the database currently connected to. The schema information is returned in the form of a DataTable. The schema information is organized into a number of collections. Different forms of the GetSchema() method can be used depending on the information required. There are three forms of the GetSchema() method:

Collections

The collections can be broadly grouped into two types: collections that are common to all data providers, and collections specific to a particular provider.

Common

The following collections are common to all data providers:

Provider-specific

The following are the collections currently provided by MariaDB Connector/Net, in addition to the common collections above:

Example Code

A list of available collections can be obtained using the following code: 

using System;
using System.Data;
using System.Text;
using MySql.Data;
using MySql.Data.MySqlClient;
namespace ConsoleApplication2
{
 class Program
 {
 private static void DisplayData(System.Data.DataTable table)
 {
 foreach (System.Data.DataRow row in table.Rows)
 {
 foreach (System.Data.DataColumn col in table.Columns)
 {
 Console.WriteLine('{0} = {1}', col.ColumnName, row[col]);
 }
 Console.WriteLine('============================');
 }
 }
 static void Main(string[] args)
 {
 string connStr = 'server=localhost;user=root;database=world;port=3306;password=******;';
 MySqlConnection conn = new MySqlConnection(connStr);
 try
 {
 Console.WriteLine('Connecting to MariaDB...');
 conn.Open();
 DataTable table = conn.GetSchema('MetaDataCollections');
 //DataTable table = conn.GetSchema('UDF');
 DisplayData(table);
 conn.Close();
 }
 catch (Exception ex)
 {
 Console.WriteLine(ex.ToString());
 }
 Console.WriteLine('Done.');
 }
 }
}

Further information on the GetSchema() method and schema collections can be found in the Microsoft .NET documentation.

Using MySqlCommand

A MySqlCommand has the CommandText and CommandType properties associated with it. The CommandText will be handled differently depending on the setting of CommandType. CommandType can be one of:

  1. Text - A SQL text command (default)
  2. StoredProcedure - The name of a Stored Procedure
  3. TableDirect - The name of a table (new in Connector/Net 6.2)

The default CommandType, Text, is used for executing queries and other SQL commands. Some example of this can be found in the following section , "The MySqlCommand Object".

If CommandType is set to StoredProcedure, set CommandText to the name of the Stored Procedure to access.

If CommandType is set to TableDirect, all rows and columns of the named table will be returned when you call one of the Execute methods. In effect, this command performs a SELECT * on the table specified. The CommandText property is set to the name of the table to query. This is illustrated by the following code snippet: 

...
MySqlCommand cmd = new MySqlCommand();
cmd.CommandText = 'mytable';
cmd.Connection = someConnection;
cmd.CommandType = CommandType.TableDirect;
MySqlDataReader reader = cmd.ExecuteReader();
while (reader.Read())
{
 Console.WriteLn(reader[0], reader[1]...);
}
...

Examples of using the CommandType of StoredProcedure can be found in the section , "Accessing Stored Procedures with Connector/Net".

Commands can have a timeout associated with them. This is useful as you may not want a situation were a command takes up an excessive amount of time. A timeout can be set using the CommandTimeout property. The following code snippet sets a timeout of one minute: 

MySqlCommand cmd = new MySqlCommand();
cmd.CommandTimeout = 60;

The default value is 30 seconds. Avoid a value of 0, which indicates an indefinite wait. To change the default command timeout, use the connection string option Default Command Timeout.

Prior to MariaDB Connector/Net 6.2, MySqlCommand.CommandTimeout included user processing time, that is processing time not related to direct use of the connector. Timeout was implemented through a .NET Timer, that triggered after CommandTimeout seconds. This timer consumed a thread.

MySQL Connector/Net 6.2 introduced timeouts that are aligned with how Microsoft handles SqlCommand.CommandTimeout. This property is the cumulative timeout for all network reads and writes during command execution or processing of the results. A timeout can still occur in the MySqlReader.Read method after the first row is returned, and does not include user processing time, only IO operations. The 6.2 implementation uses the underlying stream timeout facility, so is more efficient in that it does not require the additional timer thread as was the case with the previous implementation.

Further details on this can be found in the relevant Microsoft documentation.

Using Connector/Net with Connection Pooling

The Connector/Net supports connection pooling. This is enabled by default. You can turn it off or adjust its performance characteristics using the connection string options Pooling, Connection Reset, Connection Lifetime, Cache Server Properties, Max Pool Size and Min Pool Size. See , "Creating a Connector/Net Connection String" for further information.

Connection pooling works by keeping the native connection to the server live when the client disposes of a MySqlConnection. Subsequently, if a new MySqlConnection object is opened, it will be created from the connection pool, rather than creating a new native connection. This improves performance.

To work as designed, it is best to let the connection pooling system manage all connections. Do not create a globally accessible instance of MySqlConnection and then manually open and close it. This interferes with the way the pooling works and can lead to unpredictable results or even exceptions.

One approach that simplifies things is to avoid manually creating a MySqlConnection object. Instead use the overloaded methods that take a connection string as an argument. Using this approach, Connector/Net will automatically create, open, close and destroy connections, using the connection pooling system for best performance.

Typed Datasets and the MembershipProvider and RoleProvider classes use this approach. Most classes that have methods that take a MySqlConnection as an argument, also have methods that take a connection string as an argument. This includes MySqlDataAdapter.

Instead of manually creating MySqlCommand objects, you can use the static methods of the MySqlHelper class. These take a connection string as an argument, and they fully support connection pooling.

Starting with MariaDB Connector/Net 6.2, there is a background job that runs every three minutes and removes connections from pool that have been idle (unused) for more than three minutes. The pool cleanup frees resources on both client and server side. This is because on the client side every connection uses a socket, and on the server side every connection uses a socket and a thread.

Prior to this change, connections were never removed from the pool, and the pool always contained the peak number of open connections. For example, a web application that peaked at 1000 concurrent database connections would consume 1000 threads and 1000 open sockets at the server, without ever freeing up those resources from the connection pool. Note, connections, no matter how old, will not be closed if the number of connections in the pool is less than or equal to the value set by the Min Pool Size connection string parameter.

Using the Windows Native Authentication Plugin

Connector/Net applications can authenticate to a MariaDB server using the Windows Native Authentication Plugin as of Connector/NET 6.4.4 and MariaDB 5.5.16. Users who have logged in to Windows can connect from MariaDB client programs to the server based on the information in their environment without specifying an additional password. For background and usage information about the authentication plugin, see, The Windows Native Authentication Plugin.

The interface matches the MySql.Data.MySqlClient object. To enable, pass in Integrated Security to the connection string with a value of yes or sspi.

Passing in a user ID is optional. When Windows authentication is set up, a MariaDB user is created and configured to be used by Windows authentication. By default, this user ID is named auth_windows, but can be defined using a different name. If the default name is used, then passing the user ID to the connection string from Connector/NET is optional, because it will use the auth_windows user. Otherwise, the name must be passed to the connection string using the standard user ID element.

Using Connector/Net with Table Caching

This feature exists with Connector/NET versions 6.4 and above.

Table caching is a feature that can be used to cache slow-changing datasets on the client side. This is useful for applications that are designed to use readers, but still want to minimize trips to the server for slow-changing tables.

This feature is transparent to the application, and is disabled by default.

Configuration

Using the Connector/Net with Prepared Statements

Preparing Statements in Connector/Net

Introduction

As of MySQL, it is possible to use prepared statements with Connector/Net. Use of prepared statements can provide significant performance improvements on queries that are executed more than once.

Prepared execution is faster than direct execution for statements executed more than once, primarily because the query is parsed only once. In the case of direct execution, the query is parsed every time it is executed. Prepared execution also can provide a reduction of network traffic because for each execution of the prepared statement, it is necessary only to send the data for the parameters.

Another advantage of prepared statements is that it uses a binary protocol that makes data transfer between client and server more efficient.

Preparing Statements in Connector/Net

To prepare a statement, create a command object and set the .CommandText property to your query.

After entering your statement, call the .Prepare method of the MySqlCommand object. After the statement is prepared, add parameters for each of the dynamic elements in the query.

After you enter your query and enter parameters, execute the statement using the .ExecuteNonQuery(), .ExecuteScalar(), or .ExecuteReader methods.

For subsequent executions, you need only modify the values of the parameters and call the execute method again, there is no need to set the .CommandText property or redefine the parameters.

Visual Basic Example
Dim conn As New MySqlConnection Dim cmd As New MySqlCommand conn.ConnectionString = strConnection Try
 conn.Open()
 cmd.Connection = conn
 cmd.CommandText = 'INSERT INTO myTable VALUES(NULL, @number, @text)'
 cmd.Prepare()
 cmd.Parameters.AddWithValue('@number', 1)
 cmd.Parameters.AddWithValue('@text', 'One')
 For i = 1 To 1000
 cmd.Parameters('@number').Value = i
 cmd.Parameters('@text').Value = 'A string value'
 cmd.ExecuteNonQuery()
 Next Catch ex As MySqlException
 MessageBox.Show('Error ' & ex.Number & ' has occurred: ' & ex.Message, 'Error', MessageBoxButtons.OK, MessageBoxIcon.Error)
End Try
C# Example
MySql.Data.MySqlClient.MySqlConnection conn;
MySql.Data.MySqlClient.MySqlCommand cmd;
conn = new MySql.Data.MySqlClient.MySqlConnection();
cmd = new MySql.Data.MySqlClient.MySqlCommand();
conn.ConnectionString = strConnection;
try
{
 conn.Open();
 cmd.Connection = conn;
 cmd.CommandText = 'INSERT INTO myTable VALUES(NULL, @number, @text)';
 cmd.Prepare();
 cmd.Parameters.AddWithValue('@number', 1);
 cmd.Parameters.AddWithValue('@text', 'One');
 for (int i=1; i <= 1000; i++)
 {
 cmd.Parameters['@number'].Value = i;
 cmd.Parameters['@text'].Value = 'A string value';
 cmd.ExecuteNonQuery();
 }
}
catch (MySql.Data.MySqlClient.MySqlException ex)
{
 MessageBox.Show('Error ' + ex.Number + ' has occurred: ' + ex.Message,
 'Error', MessageBoxButtons.OK, MessageBoxIcon.Error);
}

Accessing Stored Procedures with Connector/Net

Using Stored Routines from Connector/Net

Introduction

MySQL server version 5 and up supports stored procedures with the SQL 2003 stored procedure syntax.

A stored procedure is a set of SQL statements that is stored in the server. Clients make a single call to the stored procedure, passing parameters that can influence the procedure logic and query conditions, rather than issuing individual hardcoded SQL statements.

Stored procedures can be particularly useful in situations such as the following:

Connector/Net supports the calling of stored procedures through the MySqlCommand object. Data can be passed in and out of a MariaDB stored procedure through use of the MySqlCommand.Parameters collection.Note

When you call a stored procedure, the command object makes an additional SELECT call to determine the parameters of the stored procedure. You must ensure that the user calling the procedure has the SELECT privilege on the mysql.proc table to enable them to verify the parameters. Failure to do this will result in an error when calling the procedure.

This section will not provide in-depth information on creating Stored Procedures. For such information, please refer to http://dev.mysql.com/doc/mysql/en/stored-routines.html.

A sample application demonstrating how to use stored procedures with Connector/Net can be found in the Samples directory of your Connector/Net installation.

Using Stored Routines from Connector/Net

Stored procedures in MariaDB can be created using a variety of tools. First, stored procedures can be created using the mysql command-line client. Second, stored procedures can be created using MariaDB Workbench. Finally, stored procedures can be created using the .ExecuteNonQuery method of the MySqlCommand object.

Unlike the command-line and GUI clients, you are not required to specify a special delimiter when creating stored procedures in Connector/Net.

To call a stored procedure using Connector/Net, you create a MySqlCommand object and pass the stored procedure name as the .CommandText property. You then set the .CommandType property to CommandType.StoredProcedure.

After the stored procedure is named, you create one MySqlCommand parameter for every parameter in the stored procedure. IN parameters are defined with the parameter name and the object containing the value, OUT parameters are defined with the parameter name and the data type that is expected to be returned. All parameters need the parameter direction defined.

After defining the parameters, you call the stored procedure by using the MySqlCommand.ExecuteNonQuery() method.

Once the stored procedure is called, the values of the output parameters can be retrieved by using the .Value property of the MySqlConnector.Parameters collection.Note

When a stored procedure is called using MySqlCommand.ExecuteReader, and the stored procedure has output parameters, the output parameters are only set after the MySqlDataReader returned by ExecuteReader is closed.

The following C# example code demonstrates the use of stored procedures. It assumes the database 'employees' has already been created: 

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Data;
using MySql.Data;
using MySql.Data.MySqlClient;
namespace UsingStoredRoutines
{
 class Program
 {
 static void Main(string[] args)
 {
 MySqlConnection conn = new MySqlConnection();
 conn.ConnectionString = 'server=localhost;user=root;database=employees;port=3306;password=******;';
 MySqlCommand cmd = new MySqlCommand();
 try
 {
 Console.WriteLine('Connecting to MariaDB...');
 conn.Open();
 cmd.Connection = conn;
 cmd.CommandText = 'DROP PROCEDURE IF EXISTS add_emp';
 cmd.ExecuteNonQuery();
 cmd.CommandText = 'DROP TABLE IF EXISTS emp';
 cmd.ExecuteNonQuery();
 cmd.CommandText = 'CREATE TABLE emp (empno INT UNSIGNED NOT NULL AUTO_INCREMENT PRIMARY KEY, first_name VARCHAR(20), last_name VARCHAR(20), birthdate DATE)';
 cmd.ExecuteNonQuery();
 cmd.CommandText = 'CREATE PROCEDURE add_emp(' +
 'IN fname VARCHAR(20), IN lname VARCHAR(20), IN bday DATETIME, OUT empno INT)' +
 'BEGIN INSERT INTO emp(first_name, last_name, birthdate) ' +
 'VALUES(fname, lname, DATE(bday)); SET empno = LAST_INSERT_ID(); END';
 cmd.ExecuteNonQuery();
 }
 catch (MySqlException ex)
 {
 Console.WriteLine ('Error ' + ex.Number + ' has occurred: ' + ex.Message);
 }
 conn.Close();
 Console.WriteLine('Connection closed.');
 try
 {
 Console.WriteLine('Connecting to MariaDB...');
 conn.Open();
 cmd.Connection = conn;
 cmd.CommandText = 'add_emp';
 cmd.CommandType = CommandType.StoredProcedure;
 cmd.Parameters.AddWithValue('@lname', 'Jones');
 cmd.Parameters['@lname'].Direction = ParameterDirection.Input;
 cmd.Parameters.AddWithValue('@fname', 'Tom');
 cmd.Parameters['@fname'].Direction = ParameterDirection.Input;
 cmd.Parameters.AddWithValue('@bday', '1940-06-07');
 cmd.Parameters['@bday'].Direction = ParameterDirection.Input;
 cmd.Parameters.AddWithValue('@empno', MySqlDbType.Int32);
 cmd.Parameters['@empno'].Direction = ParameterDirection.Output;
 cmd.ExecuteNonQuery();
 Console.WriteLine('Employee number: '+cmd.Parameters['@empno'].Value);
 Console.WriteLine('Birthday: ' + cmd.Parameters['@bday'].Value);
 }
 catch (MySql.Data.MySqlClient.MySqlException ex)
 {
 Console.WriteLine('Error ' + ex.Number + ' has occurred: ' + ex.Message);
 }
 conn.Close();
 Console.WriteLine('Done.');
 }
 }
}

The following code shows the same application in Visual Basic: 

Imports System Imports System.Collections.Generic Imports System.Linq Imports System.Text Imports System.Data Imports MySql.Data Imports MySql.Data.MySqlClient Module Module1
 Sub Main()
 Dim conn As New MySqlConnection()
 conn.ConnectionString = 'server=localhost;user=root;database=world;port=3306;password=******;'
 Dim cmd As New MySqlCommand()
 Try
 Console.WriteLine('Connecting to MariaDB...')
 conn.Open()
 cmd.Connection = conn
 cmd.CommandText = 'DROP PROCEDURE IF EXISTS add_emp'
 cmd.ExecuteNonQuery()
 cmd.CommandText = 'DROP TABLE IF EXISTS emp'
 cmd.ExecuteNonQuery()
 cmd.CommandText = 'CREATE TABLE emp (empno INT UNSIGNED NOT NULL AUTO_INCREMENT PRIMARY KEY, first_name VARCHAR(20), last_name VARCHAR(20), birthdate DATE)'
 cmd.ExecuteNonQuery()
 cmd.CommandText = 'CREATE PROCEDURE add_emp(' & 'IN fname VARCHAR(20), IN lname VARCHAR(20), IN bday DATETIME, OUT empno INT)' & 'BEGIN INSERT INTO emp(first_name, last_name, birthdate) ' & 'VALUES(fname, lname, DATE(bday)); SET empno = LAST_INSERT_ID(); END'
 cmd.ExecuteNonQuery()
 Catch ex As MySqlException
 Console.WriteLine(('Error ' & ex.Number & ' has occurred: ') + ex.Message)
 End Try
 conn.Close()
 Console.WriteLine('Connection closed.')
 Try
 Console.WriteLine('Connecting to MariaDB...')
 conn.Open()
 cmd.Connection = conn
 cmd.CommandText = 'add_emp'
 cmd.CommandType = CommandType.StoredProcedure
 cmd.Parameters.AddWithValue('@lname', 'Jones')
 cmd.Parameters('@lname').Direction = ParameterDirection.Input
 cmd.Parameters.AddWithValue('@fname', 'Tom')
 cmd.Parameters('@fname').Direction = ParameterDirection.Input
 cmd.Parameters.AddWithValue('@bday', '1940-06-07')
 cmd.Parameters('@bday').Direction = ParameterDirection.Input
 cmd.Parameters.AddWithValue('@empno', MySqlDbType.Int32)
 cmd.Parameters('@empno').Direction = ParameterDirection.Output
 cmd.ExecuteNonQuery()
 Console.WriteLine('Employee number: ' & cmd.Parameters('@empno').Value)
 Console.WriteLine('Birthday: ' & cmd.Parameters('@bday').Value)
 Catch ex As MySql.Data.MySqlClient.MySqlException
 Console.WriteLine(('Error ' & ex.Number & ' has occurred: ') + ex.Message)
 End Try
 conn.Close()
 Console.WriteLine('Done.')
 End Sub End Module

Handling BLOB Data With Connector/Net

Preparing the MariaDB Server
Writing a File to the Database
Reading a BLOB from the Database to a File on Disk

One common use for MariaDB is the storage of binary data in BLOB columns. MariaDB supports four different BLOB data types: TINYBLOB, BLOB, MEDIUMBLOB, and LONGBLOB, all described in , "The BLOB and TEXT Types" and , "Data Type Storage Requirements".

Data stored in a BLOB column can be accessed using Connector/Net and manipulated using client-side code. There are no special requirements for using Connector/Net with BLOB data.

Simple code examples will be presented within this section, and a full sample application can be found in the Samples directory of the Connector/Net installation.

Preparing the MariaDB Server

The first step is using MariaDB with BLOB data is to configure the server. Let's start by creating a table to be accessed. In my file tables, I usually have four columns: an AUTO_INCREMENT column of appropriate size (UNSIGNED SMALLINT) to serve as a primary key to identify the file, a VARCHAR column that stores the file name, an UNSIGNED MEDIUMINT column that stores the size of the file, and a MEDIUMBLOB column that stores the file itself. For this example, I will use the following table definition: 

CREATE TABLE file(
file_id SMALLINT UNSIGNED AUTO_INCREMENT NOT NULL PRIMARY KEY,
file_name VARCHAR(64) NOT NULL,
file_size MEDIUMINT UNSIGNED NOT NULL,
file MEDIUMBLOB NOT NULL);

After creating a table, you might need to modify the max_allowed_packet system variable. This variable determines how large of a packet (that is, a single row) can be sent to the MariaDB server. By default, the server only accepts a maximum size of 1MB from the client application. If you intend to exceed 1MB in your file transfers, increase this number.

The max_allowed_packet option can be modified using MariaDB Administrator's Startup Variables screen. Adjust the Maximum permitted option in the Memory section of the Networking tab to an appropriate setting. After adjusting the value, click the Apply Changes button and restart the server using the Service Control screen of MariaDB Administrator. You can also adjust this value directly in the my.cnf file (add a line that reads max_allowed_packet=xxM), or use the SET max_allowed_packet=xxM; syntax from within MySQL.

Try to be conservative when setting max_allowed_packet, as transfers of BLOB data can take some time to complete. Try to set a value that will be adequate for your intended use and increase the value if necessary.

Writing a File to the Database

To write a file to a database, we need to convert the file to a byte array, then use the byte array as a parameter to an INSERT query.

The following code opens a file using a FileStream object, reads it into a byte array, and inserts it into the file table:

Visual Basic Example
Dim conn As New MySqlConnection Dim cmd As New MySqlCommand Dim SQL As String Dim FileSize As UInt32
Dim rawData() As Byte Dim fs As FileStream conn.ConnectionString = 'server=127.0.0.1;' _
 & 'uid=root;' _
 & 'pwd=12345;' _
 & 'database=test'
Try
 fs = New FileStream('c:\image.png', FileMode.Open, FileAccess.Read)
 FileSize = fs.Length
 rawData = New Byte(FileSize) {}
 fs.Read(rawData, 0, FileSize)
 fs.Close()
 conn.Open()
 SQL = 'INSERT INTO file VALUES(NULL, @FileName, @FileSize, @File)'
 cmd.Connection = conn
 cmd.CommandText = SQL
 cmd.Parameters.AddWithValue('@FileName', strFileName)
 cmd.Parameters.AddWithValue('@FileSize', FileSize)
 cmd.Parameters.AddWithValue('@File', rawData)
 cmd.ExecuteNonQuery()
 MessageBox.Show('File Inserted into database successfully!', _
 'Success!', MessageBoxButtons.OK, MessageBoxIcon.Asterisk)
 conn.Close()
Catch ex As Exception
 MessageBox.Show('There was an error: ' & ex.Message, 'Error', _
 MessageBoxButtons.OK, MessageBoxIcon.Error)
End Try
C# Example
MySql.Data.MySqlClient.MySqlConnection conn;
MySql.Data.MySqlClient.MySqlCommand cmd;
conn = new MySql.Data.MySqlClient.MySqlConnection();
cmd = new MySql.Data.MySqlClient.MySqlCommand();
string SQL;
UInt32 FileSize;
byte[] rawData;
FileStream fs;
conn.ConnectionString = 'server=127.0.0.1;uid=root;' +
 'pwd=12345;database=test;';
try
{
 fs = new FileStream(@'c:\image.png', FileMode.Open, FileAccess.Read);
 FileSize = fs.Length;
 rawData = new byte[FileSize];
 fs.Read(rawData, 0, FileSize);
 fs.Close();
 conn.Open();
 SQL = 'INSERT INTO file VALUES(NULL, @FileName, @FileSize, @File)';
 cmd.Connection = conn;
 cmd.CommandText = SQL;
 cmd.Parameters.AddWithValue('@FileName', strFileName);
 cmd.Parameters.AddWithValue('@FileSize', FileSize);
 cmd.Parameters.AddWithValue('@File', rawData);
 cmd.ExecuteNonQuery();
 MessageBox.Show('File Inserted into database successfully!',
 'Success!', MessageBoxButtons.OK, MessageBoxIcon.Asterisk);
 conn.Close();
}
catch (MySql.Data.MySqlClient.MySqlException ex)
{
 MessageBox.Show('Error ' + ex.Number + ' has occurred: ' + ex.Message,
 'Error', MessageBoxButtons.OK, MessageBoxIcon.Error);
}

The Read method of the FileStream object is used to load the file into a byte array which is sized according to the Length property of the FileStream object.

After assigning the byte array as a parameter of the MySqlCommand object, the ExecuteNonQuery method is called and the BLOB is inserted into the file table.

Reading a BLOB from the Database to a File on Disk

Once a file is loaded into the file table, we can use the MySqlDataReader class to retrieve it.

The following code retrieves a row from the file table, then loads the data into a FileStream object to be written to disk:

Visual Basic Example
Dim conn As New MySqlConnection Dim cmd As New MySqlCommand Dim myData As MySqlDataReader Dim SQL As String Dim rawData() As Byte Dim FileSize As UInt32
Dim fs As FileStream conn.ConnectionString = 'server=127.0.0.1;' _
 & 'uid=root;' _
 & 'pwd=12345;' _
 & 'database=test'
SQL = 'SELECT file_name, file_size, file FROM file'
Try
 conn.Open()
 cmd.Connection = conn
 cmd.CommandText = SQL
 myData = cmd.ExecuteReader
 If Not myData.HasRows Then Throw New Exception('There are no BLOBs to save')
 myData.Read()
 FileSize = myData.GetUInt32(myData.GetOrdinal('file_size'))
 rawData = New Byte(FileSize) {}
 myData.GetBytes(myData.GetOrdinal('file'), 0, rawData, 0, FileSize)
 fs = New FileStream('C:\newfile.png', FileMode.OpenOrCreate, FileAccess.Write)
 fs.Write(rawData, 0, FileSize)
 fs.Close()
 MessageBox.Show('File successfully written to disk!', 'Success!', MessageBoxButtons.OK, MessageBoxIcon.Asterisk)
 myData.Close()
 conn.Close()
Catch ex As Exception
 MessageBox.Show('There was an error: ' & ex.Message, 'Error', MessageBoxButtons.OK, MessageBoxIcon.Error)
End Try
C# Example
MySql.Data.MySqlClient.MySqlConnection conn;
MySql.Data.MySqlClient.MySqlCommand cmd;
MySql.Data.MySqlClient.MySqlDataReader myData;
conn = new MySql.Data.MySqlClient.MySqlConnection();
cmd = new MySql.Data.MySqlClient.MySqlCommand();
string SQL;
UInt32 FileSize;
byte[] rawData;
FileStream fs;
conn.ConnectionString = 'server=127.0.0.1;uid=root;' +
 'pwd=12345;database=test;';
SQL = 'SELECT file_name, file_size, file FROM file';
try
{
 conn.Open();
 cmd.Connection = conn;
 cmd.CommandText = SQL;
 myData = cmd.ExecuteReader();
 if (! myData.HasRows)
 throw new Exception('There are no BLOBs to save');
 myData.Read();
 FileSize = myData.GetUInt32(myData.GetOrdinal('file_size'));
 rawData = new byte[FileSize];
 myData.GetBytes(myData.GetOrdinal('file'), 0, rawData, 0, (int)FileSize);
 fs = new FileStream(@'C:\newfile.png', FileMode.OpenOrCreate, FileAccess.Write);
 fs.Write(rawData, 0, (int)FileSize);
 fs.Close();
 MessageBox.Show('File successfully written to disk!',
 'Success!', MessageBoxButtons.OK, MessageBoxIcon.Asterisk);
 myData.Close();
 conn.Close();
}
catch (MySql.Data.MySqlClient.MySqlException ex)
{
 MessageBox.Show('Error ' + ex.Number + ' has occurred: ' + ex.Message,
 'Error', MessageBoxButtons.OK, MessageBoxIcon.Error);
}

After connecting, the contents of the file table are loaded into a MySqlDataReader object. The GetBytes method of the MySqlDataReader is used to load the BLOB into a byte array, which is then written to disk using a FileStream object.

The GetOrdinal method of the MySqlDataReader can be used to determine the integer index of a named column. Use of the GetOrdinal method prevents errors if the column order of the SELECT query is changed.

Using the Connector/Net Interceptor Classes

An interceptor is a software design pattern that provides a transparent way to extend or modify some aspect of a program, similar to a user exit. No recompiling is required. With Connector/Net, the interceptors are enabled and disabled by updating the connection string to refer to different sets of interceptor classes that you instantiate.

Connector/Net includes the following interceptor classes:

Here are examples of using the FQN (fully qualified name) on the connection string: 

MySqlConnection c1 = new MySqlConnection(@'server=localhost;pooling=false;
commandinterceptors=CommandApp.MyCommandInterceptor,CommandApp');
MySqlConnection c2 = new MySqlConnection(@'server=localhost;pooling=false;
exceptioninterceptors=ExceptionStackTraceTest.MyExceptionInterceptor,ExceptionStackTraceTest');

In this example, the command interceptor is called CommandApp.MyCommandInterceptor and exists in the CommandApp assembly. The exception interceptor is called ExceptionStackTraceTest.MyExceptionInterceptor and exists in the ExceptionStackTraceTest assembly.

To shorten the connection string, you can register your exception interceptors in your app.config or web.config file like this: 

<configSections>
<section name="MySQL" type="MySql.Data.MySqlClient.MySqlConfiguration, 
MySql.Data"/>
</configSections>
<MySQL>
<CommandInterceptors>
 <add name="myC" type="CommandApp.MyCommandInterceptor,CommandApp" />
</CommandInterceptors>
</MySQL>
<configSections>
<section name="MySQL" type="MySql.Data.MySqlClient.MySqlConfiguration, 
MySql.Data"/>
</configSections>
<MySQL>
<ExceptionInterceptors>
 <add name="myE" 
type='ExceptionStackTraceTest.MyExceptionInterceptor,ExceptionStackTraceTest' />
</ExceptionInterceptors>
</MySQL>

Once you have done that, your connection strings can look like these: 

MySqlConnection c1 = new MySqlConnection(@'server=localhost;pooling=false;
commandinterceptors=myC');
MySqlConnection c2 = new MySqlConnection(@'server=localhost;pooling=false;
exceptioninterceptors=myE');

Handling Date and Time Information in Connector/Net

Fractional Seconds
Problems when Using Invalid Dates
Restricting Invalid Dates
Handling Invalid Dates
Handling NULL Dates

Introduction

MySQL and the .NET languages handle date and time information differently, with MariaDB allowing dates that cannot be represented by a .NET data type, such as '0000-00-00 00:00:00'. These differences can cause problems if not properly handled.

The following sections demonstrate how to properly handle date and time information when using Connector/Net.

Fractional Seconds

Connector/Net 6.5 and higher support the fractional seconds feature introduced in MariaDB 5.6.4. Fractional seconds could always be specified in a date literal or passed back and forth as parameters and return values, but the fractional part was always stripped off when stored in a table column. In MariaDB 5.6.4 and higher, the fractional part is now preserved in data stored and retrieved through SQL. For fractional second handling in MariaDB 5.6.4 and higher, see , "Fractional Seconds in Time Values". For the behavior of fractional seconds prior to MariaDB 5.6.4, see Fractional Seconds in Time Values.

To use the more precise date and time types, specify a value from 1 to 6 when creating the table column, for example TIME(3) or DATETIME(6), representing the number of digits of precision after the decimal point. Specifying a precision of 0 leaves the fractional part out entirely. In your C# or Visual Basic code, refer to the Millisecond member to retrieve the fractional second value from the MySqlDateTime object returned by the GetMySqlDateTime function. The DateTime object returned by the GetDateTime function also contains the fractional value, but only the first 3 digits.

For related code examples, see the following blog post: https://blogs.oracle.com/MySqlOnWindows/entry/milliseconds_value_support_on_datetime

Problems when Using Invalid Dates

The differences in date handling can cause problems for developers who use invalid dates. Invalid MariaDB dates cannot be loaded into native .NET DateTime objects, including NULL dates.

Because of this issue, .NET DataSet objects cannot be populated by the Fill method of the MySqlDataAdapter class as invalid dates will cause a System.ArgumentOutOfRangeException exception to occur.

Restricting Invalid Dates

The best solution to the date problem is to restrict users from entering invalid dates. This can be done on either the client or the server side.

Restricting invalid dates on the client side is as simple as always using the .NET DateTime class to handle dates. The DateTime class will only allow valid dates, ensuring that the values in your database are also valid. The disadvantage of this is that it is not useful in a mixed environment where .NET and non .NET code are used to manipulate the database, as each application must perform its own date validation.

Users of MariaDB 5.0.2 and higher can use the new traditional SQL mode to restrict invalid date values. For information on using the traditional SQL mode, see , "Server SQL Modes".

Handling Invalid Dates

Although it is strongly recommended that you avoid the use of invalid dates within your .NET application, it is possible to use invalid dates by means of the MySqlDateTime data type.

The MySqlDateTime data type supports the same date values that are supported by the MariaDB server. The default behavior of Connector/Net is to return a .NET DateTime object for valid date values, and return an error for invalid dates. This default can be modified to cause Connector/Net to return MySqlDateTime objects for invalid dates.

To instruct Connector/Net to return a MySqlDateTime object for invalid dates, add the following line to your connection string: 

Allow Zero Datetime=True

Please note that the use of the MySqlDateTime class can still be problematic. The following are some known issues:

  1. Data binding for invalid dates can still cause errors (zero dates like 0000-00-00 do not seem to have this problem).
  2. The ToString method return a date formatted in the standard MariaDB format (for example, 2005-02-23 08:50:25). This differs from the ToString behavior of the .NET DateTime class.
  3. The MySqlDateTime class supports NULL dates, while the .NET DateTime class does not. This can cause errors when trying to convert a MySQLDateTime to a DateTime if you do not check for NULL first.

Because of the known issues, the best recommendation is still to use only valid dates in your application.

Handling NULL Dates

The .NET DateTime data type cannot handle NULL values. As such, when assigning values from a query to a DateTime variable, you must first check whether the value is in fact NULL.

When using a MySqlDataReader, use the .IsDBNull method to check whether a value is NULL before making the assignment:

Visual Basic Example
If Not myReader.IsDBNull(myReader.GetOrdinal('mytime')) Then
 myTime = myReader.GetDateTime(myReader.GetOrdinal('mytime'))
Else
 myTime = DateTime.MinValue End If
C# Example
if (! myReader.IsDBNull(myReader.GetOrdinal('mytime')))
 myTime = myReader.GetDateTime(myReader.GetOrdinal('mytime'));
else
 myTime = DateTime.MinValue;

NULL values will work in a data set and can be bound to form controls without special handling.

Using the MySqlBulkLoader Class

MySQL Connector/Net features a bulk loader class that wraps the MariaDB statement LOAD DATA INFILE. This gives MariaDB Connector/Net the ability to load a data file from a local or remote host to the server. The class concerned is MySqlBulkLoader. This class has various methods, the main one being load to cause the specified file to be loaded to the server. Various parameters can be set to control how the data file is processed. This is achieved through setting various properties of the class. For example, the field separator used, such as comma or tab, can be specified, along with the record terminator, such as newline.

The following code shows a simple example of using the MySqlBulkLoader class. First an empty table needs to be created, in this case in the test database: 

CREATE TABLE Career (
 Name VARCHAR(100) NOT NULL,
 Age INTEGER,
 Profession VARCHAR(200)
);

A simple tab-delimited data file is also created (it could use any other field delimiter such as comma): 

Table Career in Test Database Name Age Profession Tony 47 Technical Writer Ana 43 Nurse Fred 21 IT Specialist Simon 45 Hairy Biker

Note that with this test file the first three lines will need to be ignored, as they do not contain table data. This can be achieved using the NumberOfLinesToSkip property. This file can then be loaded and used to populate the Career table in the test database: 

using System;
using System.Text;
using MySql.Data;
using MySql.Data.MySqlClient;
namespace ConsoleApplication1
{
 class Program
 {
 static void Main(string[] args)
 {
 string connStr = 'server=localhost;user=root;database=test;port=3306;password=******;';
 MySqlConnection conn = new MySqlConnection(connStr);
 MySqlBulkLoader bl = new MySqlBulkLoader(conn);
 bl.TableName = 'Career';
 bl.FieldTerminator = '\t';
 bl.LineTerminator = '\n';
 bl.FileName = 'c:/career_data.txt';
 bl.NumberOfLinesToSkip = 3;
 try
 {
 Console.WriteLine('Connecting to MariaDB...');
 conn.Open();
 // Upload data from file
 int count = bl.Load();
 Console.WriteLine(count + ' lines uploaded.');
 string sql = 'SELECT Name, Age, Profession FROM Career';
 MySqlCommand cmd = new MySqlCommand(sql, conn);
 MySqlDataReader rdr = cmd.ExecuteReader();
 while (rdr.Read())
 {
 Console.WriteLine(rdr[0] + ' -- ' + rdr[1] + ' -- ' + rdr[2]);
 }
 rdr.Close();
 conn.Close();
 }
 catch (Exception ex)
 {
 Console.WriteLine(ex.ToString());
 }
 Console.WriteLine('Done.');
 }
 }
}

Further information on LOAD DATA INFILE can be found in , "LOAD DATA INFILE Syntax". Further information on MySqlBulkLoader can be found in the reference documentation that was included with your connector.

Using the MariaDB Connector/Net Trace Source Object

Viewing MariaDB Trace Information
Building Custom Listeners

MySQL Connector/Net 6.2 introduced support for .NET 2.0 compatible tracing, using TraceSource objects.

The .NET 2.0 tracing architecture consists of four main parts:

To use tracing a TraceSource object first needs to be created. To create a TraceSource object in MariaDB Connector/Net you would use code similar to the following: 

TraceSource ts = new TraceSource('mysql');

To enable trace messages, configure a trace switch. There are three main switch classes, BooleanSwitch, SourceSwitch, and TraceSwitch. Trace switches also have associated with them a trace level enumeration, these are Off, Error, Warning, Info, and Verbose. The following code snippet illustrates creating a switch: 

ts.Switch = new SourceSwitch('MySwitch', 'Verbose');

This creates a SourceSwitch, called MySwitch, and sets the trace level to Verbose, meaning that all trace messages will be written.

It is convenient to be able to change the trace level without having to recompile the code. This is achieved by specifying the trace level in application configuration file, app.config. You then simply need to specify the desired trace level in the configuration file and restart the application. The trace source is configured within the system.diagnostics section of the file. The following XML snippet illustrates this: 

<configuration>
 ...
 <system.diagnostics>
 <sources>
 <source name="mysql" switchName="MySwitch"
 switchType="System.Diagnostics.SourceSwitch" />
 ...
 </sources>
 <switches>
 <add name="MySwitch" value="Verbose"/>
 ...
 </switches>
 </system.diagnostics>
 ...
</configuration>

By default, trace information is written to the Output window of Microsoft Visual Studio. There are a wide range of listeners that can be attached to the trace source, so that trace messages can be written out to various destinations. You can also create custom listeners to allow trace messages to be written to other destinations as mobile devices and web services. A commonly used example of a listener is ConsoleTraceListener, which writes trace messages to the console.

To add a listener at run time, use code such as the following: 

ts.Listeners.Add(new ConsoleTraceListener());

Then, call methods on the trace source object to generate trace information. For example, the TraceInformation(), TraceEvent(), or TraceData() methods can be used.

The TraceInformation() method simply prints a string passed as a parameter. The TraceEvent() method, as well as the optional informational string, requires a TraceEventType value to be passed to indicate the trace message type, and also an application specific ID. The TraceEventType can have a value of Verbose, Information, Warning, Error, and Critical. Using the TraceData() method you can pass any object, for example an exception object, instead of a message.

To ensure than these generated trace messages gets flushed from the trace source buffers to listeners, invoke the Flush() method. When you are finished using a trace source, call the Close() method. The Close() method first calls Flush(), to ensure any remaining data is written out. It then frees up resources, and closes the listeners associated with the trace source. 

ts.TraceInformation('Informational message');
ts.TraceEvent(TraceEventType.Error, 3, 'Optional error message');
ts.TraceData(TraceEventType.Error, 3, ex); // pass exception object ts.Flush();
...
ts.Close();
Viewing MariaDB Trace Information

This section describes how to set up your application to view MariaDB trace information.

The first thing you need to do is create a suitable app.config file for your application. An example is shown in the following code: 

<?xml version="1.0" encoding="utf-8" ?>
<configuration>
 <system.diagnostics>
 <sources>
 <source name="mysql" switchName="SourceSwitch"
 switchType="System.Diagnostics.SourceSwitch" >
 <listeners>
 <add name="console" />
 <remove name ='Default' />
 </listeners>
 </source>
 </sources>
 <switches>
 <!-- You can set the level at which tracing is to occur -->
 <add name="SourceSwitch" value="Verbose" />
 <!-- You can turn tracing off -->
 <!--add name="SourceSwitch" value="Off" -->
 </switches>
 <sharedListeners>
 <add name="console"
 type="System.Diagnostics.ConsoleTraceListener"
 initializeData="false"/>
 </sharedListeners>
 </system.diagnostics>
</configuration>

This ensures a suitable trace source is created, along with a switch. The switch level in this case is set to Verbose to display the maximum amount of information.

In the application the only other step required is to add logging=true to the connection string. An example application could be: 

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Diagnostics;
using MySql.Data;
using MySql.Data.MySqlClient;
using MySql.Web;
namespace ConsoleApplication1
{
 class Program
 {
 static void Main(string[] args)
 {
 string connStr = 'server=localhost;user=root;database=world;port=3306;password=******;logging=true;';
 MySqlConnection conn = new MySqlConnection(connStr);
 try
 {
 Console.WriteLine('Connecting to MariaDB...');
 conn.Open();
 string sql = 'SELECT Name, HeadOfState FROM Country WHERE Continent="Oceania"';
 MySqlCommand cmd = new MySqlCommand(sql, conn);
 MySqlDataReader rdr = cmd.ExecuteReader();
 while (rdr.Read())
 {
 Console.WriteLine(rdr[0] + ' -- ' + rdr[1]);
 }
 rdr.Close();
 conn.Close();
 }
 catch (Exception ex)
 {
 Console.WriteLine(ex.ToString());
 }
 Console.WriteLine('Done.');
 }
 }
}

This simple application will then generate the following output: 

Connecting to MariaDB...
mysql Information: 1 : 1: Connection Opened: connection string = 'server=localhost;User Id=root;database=world;port=3306
;password=******;logging=True'
mysql Information: 3 : 1: Query Opened: SHOW VARIABLES mysql Information: 4 : 1: Resultset Opened: field(s) = 2, affected rows = -1, inserted id = -1
mysql Information: 5 : 1: Resultset Closed. Total rows=272, skipped rows=0, size (bytes)=7058
mysql Information: 6 : 1: Query Closed mysql Information: 3 : 1: Query Opened: SHOW COLLATION mysql Information: 4 : 1: Resultset Opened: field(s) = 6, affected rows = -1, inserted id = -1
mysql Information: 5 : 1: Resultset Closed. Total rows=127, skipped rows=0, size (bytes)=4102
mysql Information: 6 : 1: Query Closed mysql Information: 3 : 1: Query Opened: SET character_set_results=NULL mysql Information: 4 : 1: Resultset Opened: field(s) = 0, affected rows = 0, inserted id = 0
mysql Information: 5 : 1: Resultset Closed. Total rows=0, skipped rows=0, size (bytes)=0
mysql Information: 6 : 1: Query Closed mysql Information: 10 : 1: Set Database: world mysql Information: 3 : 1: Query Opened: SELECT Name, HeadOfState FROM Country WHERE Continent="Oceania"
mysql Information: 4 : 1: Resultset Opened: field(s) = 2, affected rows = -1, inserted id = -1
American Samoa -- George W. Bush Australia -- Elisabeth II
...
Wallis and Futuna -- Jacques Chirac Vanuatu -- John Bani United States Minor Outlying Islands -- George W. Bush mysql Information: 5 : 1: Resultset Closed. Total rows=28, skipped rows=0, size (bytes)=788
mysql Information: 6 : 1: Query Closed Done.
mysql Information: 2 : 1: Connection Closed

The first number displayed in the trace message corresponds to the MariaDB event type:

Event Description
1 ConnectionOpened: connection string
2 ConnectionClosed:
3 QueryOpened: mysql server thread id, query text
4 ResultOpened: field count, affected rows (-1 if select), inserted id (-1 if select)
5 ResultClosed: total rows read, rows skipped, size of resultset in bytes
6 QueryClosed:
7 StatementPrepared: prepared sql, statement id
8 StatementExecuted: statement id, mysql server thread id
9 StatementClosed: statement id
10 NonQuery: [varies]
11 UsageAdvisorWarning: usage advisor flag. NoIndex = 1, BadIndex = 2, SkippedRows = 3, SkippedColumns = 4, FieldConversion = 5.
12 Warning: level, code, message
13 Error: error number, error message

The second number displayed in the trace message is the connection count.

Although this example uses the ConsoleTraceListener, any of the other standard listeners could have been used. Another possibility is to create a custom listener that uses the information passed using the TraceEvent method. For example, a custom trace listener could be created to perform active monitoring of the MariaDB event messages, rather than simply writing these to an output device.

It is also possible to add listeners to the MariaDB Trace Source at run time. This can be done with the following code: 

MySqlTrace.Listeners.Add(new ConsoleTraceListener());

MySQL Connector/Net 6.3.2 introduced the ability to switch tracing on and off at run time. This can be achieved using the calls MySqlTrace.EnableQueryAnalyzer(string host, int postInterval) and MySqlTrace.DisableQueryAnalyzer(). The parameter host is the URL of the MariaDB Enterprise Monitor server to monitor. The parameter postInterval is how often to post the data to MariaDB Enterprise Monitor, in seconds.

Building Custom Listeners

To build custom listeners that work with the MariaDB Connector/Net Trace Source, it is necessary to understand the key methods used, and the event data formats used.

The main method involved in passing trace messages is the TraceSource.TraceEvent method. This has the prototype: 

public void TraceEvent(
 TraceEventType eventType,
 int id,
 string format,
 params Object[] args
)

This trace source method will process the list of attached listeners and call the listener's TraceListener.TraceEvent method. The prototype for the TraceListener.TraceEvent method is as follows: 

public virtual void TraceEvent(
 TraceEventCache eventCache,
 string source,
 TraceEventType eventType,
 int id,
 string format,
 params Object[] args
)

The first three parameters are used in the standard as defined by Microsoft. The last three parameters contain MySQL-specific trace information. Each of these parameters is now discussed in more detail.

int id

This is a MySQL-specific identifier. It identifies the MariaDB event type that has occurred, resulting in a trace message being generated. This value is defined by the MySqlTraceEventType public enum contained in the MariaDB Connector/Net code: 

public enum MySqlTraceEventType : int
{
 ConnectionOpened = 1,
 ConnectionClosed,
 QueryOpened,
 ResultOpened,
 ResultClosed,
 QueryClosed,
 StatementPrepared,
 StatementExecuted,
 StatementClosed,
 NonQuery,
 UsageAdvisorWarning,
 Warning,
 Error
}

The MariaDB event type also determines the contents passed using the parameter params Object[] args. The nature of the args parameters are described in further detail in the following material.

string format

This is the format string that contains zero or more format items, which correspond to objects in the args array. This would be used by a listener such as ConsoleTraceListener to write a message to the output device.

params Object[] args

This is a list of objects that depends on the MariaDB event type, id. However, the first parameter passed using this list is always the driver id. The driver id is a unique number that is incremented each time the connector is opened. This enables groups of queries on the same connection to be identified. The parameters that follow driver id depend of the MariaDB event id, and are as follows:

MySQL-specific event type Arguments (params Object[] args)
ConnectionOpened Connection string
ConnectionClosed No additional parameters
QueryOpened mysql server thread id, query text
ResultOpened field count, affected rows (-1 if select), inserted id (-1 if select)
ResultClosed total rows read, rows skipped, size of resultset in bytes
QueryClosed No additional parameters
StatementPrepared prepared sql, statement id
StatementExecuted statement id, mysql server thread id
StatementClosed statement id
NonQuery Varies
UsageAdvisorWarning usage advisor flag. NoIndex = 1, BadIndex = 2, SkippedRows = 3, SkippedColumns = 4, FieldConversion = 5.
Warning level, code, message
Error error number, error message

This information will allow you to create custom trace listeners that can actively monitor the MySQL-specific events.

Binary/Nonbinary Issues

There are certain situations where MariaDB will return incorrect metadata about one or more columns. More specifically, the server will sometimes report that a column is binary when it is not and vice versa. In these situations, it becomes practically impossible for the connector to be able to correctly identify the correct metadata.

Some examples of situations that may return incorrect metadata are:

With the availability of BINARY and VARBINARY data types, it is important that we respect the metadata returned by the server. However, we are aware that some existing applications may break with this change, so we are creating a connection string option to enable or disable it. By default, Connector/Net 5.1 respects the binary flags returned by the server. You might need to make small changes to your application to accommodate this change.

In the event that the changes required to your application would be too large, adding 'respect binary flags=false' to your connection string causes the connector to use the prior behavior: any column that is marked as string, regardless of binary flags, will be returned as string. Only columns that are specifically marked as a BLOB will be returned as BLOB.

Character Set Considerations for Connector/Net

Treating Binary Blobs As UTF8

MySQL doesn't currently support 4-byte UTF8 sequences. This makes it difficult to represent some multi-byte languages such as Japanese. To try and alleviate this, Connector/Net now supports a mode where binary blobs can be treated as strings.

To do this, you set the 'Treat Blobs As UTF8' connection string keyword to yes. This is all that needs to be done to enable conversion of all binary blobs to UTF8 strings. To convert only some of your BLOB columns, you can make use of the 'BlobAsUTF8IncludePattern' and'BlobAsUTF8ExcludePattern' keywords. Set these to a regular expression pattern that matches the column names to include or exclude respectively.

When the regular expression patterns both match a single column, the include pattern is applied before the exclude pattern. The result, in this case, would be that the column would be excluded. Also, be aware that this mode does not apply to columns of type BINARY or VARBINARY and also do not apply to nonbinary BLOB columns.

Currently, this mode only applies to reading strings out of MySQL. To insert 4-byte UTF8 strings into blob columns, use the .NET Encoding.GetBytes function to convert your string to a series of bytes. You can then set this byte array as a parameter for a BLOB column.

Using Connector/Net with Crystal Reports

Creating a Data Source
Creating the Report
Displaying the Report

Introduction

Crystal Reports is a common tool used by Windows application developers to perform reporting and document generation. In this section we will show how to use Crystal Reports XI with MariaDB and Connector/Net.

Creating a Data Source

When creating a report in Crystal Reports there are two options for accessing the MariaDB data while designing your report.

The first option is to use Connector/ODBC as an ADO data source when designing your report. You will be able to browse your database and choose tables and fields using drag and drop to build your report. The disadvantage of this approach is that additional work must be performed within your application to produce a data set that matches the one expected by your report.

The second option is to create a data set in VB.NET and save it as XML. This XML file can then be used to design a report. This works quite well when displaying the report in your application, but is less versatile at design time because you must choose all relevant columns when creating the data set. If you forget a column you must re-create the data set before the column can be added to the report.

The following code can be used to create a data set from a query and write it to disk:

Visual Basic Example
Dim myData As New DataSet Dim conn As New MySqlConnection Dim cmd As New MySqlCommand Dim myAdapter As New MySqlDataAdapter conn.ConnectionString = 'server=127.0.0.1;' _
 & 'uid=root;' _
 & 'pwd=12345;' _
 & 'database=world'
Try
 conn.Open()
 cmd.CommandText = 'SELECT city.name AS cityName, city.population AS CityPopulation, ' _
 & 'country.name, country.population, country.continent ' _
 & 'FROM country, city ORDER BY country.continent, country.name'
 cmd.Connection = conn
 myAdapter.SelectCommand = cmd
 myAdapter.Fill(myData)
 myData.WriteXml('C:\dataset.xml', XmlWriteMode.WriteSchema)
Catch ex As Exception
 MessageBox.Show(ex.Message, 'Report could not be created', MessageBoxButtons.OK, MessageBoxIcon.Error)
End Try
C# Example
DataSet myData = new DataSet();
MySql.Data.MySqlClient.MySqlConnection conn;
MySql.Data.MySqlClient.MySqlCommand cmd;
MySql.Data.MySqlClient.MySqlDataAdapter myAdapter;
conn = new MySql.Data.MySqlClient.MySqlConnection();
cmd = new MySql.Data.MySqlClient.MySqlCommand();
myAdapter = new MySql.Data.MySqlClient.MySqlDataAdapter();
conn.ConnectionString = 'server=127.0.0.1;uid=root;' +
 'pwd=12345;database=test;';
try
{
 cmd.CommandText = 'SELECT city.name AS cityName, city.population AS CityPopulation, ' +
 'country.name, country.population, country.continent ' +
 'FROM country, city ORDER BY country.continent, country.name';
 cmd.Connection = conn;
 myAdapter.SelectCommand = cmd;
 myAdapter.Fill(myData);
 myData.WriteXml(@'C:\dataset.xml', XmlWriteMode.WriteSchema);
}
catch (MySql.Data.MySqlClient.MySqlException ex)
{
 MessageBox.Show(ex.Message, 'Report could not be created',
 MessageBoxButtons.OK, MessageBoxIcon.Error);
}

The resulting XML file can be used as an ADO.NET XML datasource when designing your report.

If you choose to design your reports using Connector/ODBC, it can be downloaded from dev.mysql.com.

Creating the Report

For most purposes, the Standard Report wizard helps with the initial creation of a report. To start the wizard, open Crystal Reports and choose the New > Standard Report option from the File menu.

The wizard first prompts you for a data source. If you use Connector/ODBC as your data source, use the OLEDB provider for ODBC option from the OLE DB (ADO) tree instead of the ODBC (RDO) tree when choosing a data source. If using a saved data set, choose the ADO.NET (XML) option and browse to your saved data set.

The remainder of the report creation process is done automatically by the wizard.

After the report is created, choose the Report Options... entry of the File menu. Un-check the Save Data With Report option. This prevents saved data from interfering with the loading of data within our application.

Displaying the Report

To display a report we first populate a data set with the data needed for the report, then load the report and bind it to the data set. Finally we pass the report to the crViewer control for display to the user.

The following references are needed in a project that displays a report:

The following code assumes that you created your report using a data set saved using the code shown in , "Creating a Data Source", and have a crViewer control on your form named myViewer.

Visual Basic Example
Imports CrystalDecisions.CrystalReports.Engine Imports System.Data Imports MySql.Data.MySqlClient Dim myReport As New ReportDocument Dim myData As New DataSet Dim conn As New MySqlConnection Dim cmd As New MySqlCommand Dim myAdapter As New MySqlDataAdapter conn.ConnectionString = _
 'server=127.0.0.1;' _
 & 'uid=root;' _
 & 'pwd=12345;' _
 & 'database=test'
Try
 conn.Open()
 cmd.CommandText = 'SELECT city.name AS cityName, city.population AS CityPopulation, ' _
 & 'country.name, country.population, country.continent ' _
 & 'FROM country, city ORDER BY country.continent, country.name'
 cmd.Connection = conn
 myAdapter.SelectCommand = cmd
 myAdapter.Fill(myData)
 myReport.Load('.\world_report.rpt')
 myReport.SetDataSource(myData)
 myViewer.ReportSource = myReport Catch ex As Exception
 MessageBox.Show(ex.Message, 'Report could not be created', MessageBoxButtons.OK, MessageBoxIcon.Error)
End Try
C# Example
using CrystalDecisions.CrystalReports.Engine;
using System.Data;
using MySql.Data.MySqlClient;
ReportDocument myReport = new ReportDocument();
DataSet myData = new DataSet();
MySql.Data.MySqlClient.MySqlConnection conn;
MySql.Data.MySqlClient.MySqlCommand cmd;
MySql.Data.MySqlClient.MySqlDataAdapter myAdapter;
conn = new MySql.Data.MySqlClient.MySqlConnection();
cmd = new MySql.Data.MySqlClient.MySqlCommand();
myAdapter = new MySql.Data.MySqlClient.MySqlDataAdapter();
conn.ConnectionString = 'server=127.0.0.1;uid=root;' +
 'pwd=12345;database=test;';
try
{
 cmd.CommandText = 'SELECT city.name AS cityName, city.population AS CityPopulation, ' +
 'country.name, country.population, country.continent ' +
 'FROM country, city ORDER BY country.continent, country.name';
 cmd.Connection = conn;
 myAdapter.SelectCommand = cmd;
 myAdapter.Fill(myData);
 myReport.Load(@'.\world_report.rpt');
 myReport.SetDataSource(myData);
 myViewer.ReportSource = myReport;
}
catch (MySql.Data.MySqlClient.MySqlException ex)
{
 MessageBox.Show(ex.Message, 'Report could not be created',
 MessageBoxButtons.OK, MessageBoxIcon.Error);
}

A new data set it generated using the same query used to generate the previously saved data set. Once the data set is filled, a ReportDocument is used to load the report file and bind it to the data set. The ReportDocument is the passed as the ReportSource of the crViewer.

This same approach is taken when a report is created from a single table using Connector/ODBC. The data set replaces the table used in the report and the report is displayed properly.

When a report is created from multiple tables using Connector/ODBC, a data set with multiple tables must be created in our application. This enables each table in the report data source to be replaced with a report in the data set.

We populate a data set with multiple tables by providing multiple SELECT statements in our MySqlCommand object. These SELECT statements are based on the SQL query shown in Crystal Reports in the Database menu's Show SQL Query option. Assume the following query: 

SELECT `country`.`Name`, `country`.`Continent`, `country`.`Population`, `city`.`Name`, `city`.`Population`
FROM `world`.`country` `country` LEFT OUTER JOIN `world`.`city` `city` ON `country`.`Code`=`city`.`CountryCode`
ORDER BY `country`.`Continent`, `country`.`Name`, `city`.`Name`

This query is converted to two SELECT queries and displayed with the following code:

Visual Basic Example
Imports CrystalDecisions.CrystalReports.Engine Imports System.Data Imports MySql.Data.MySqlClient Dim myReport As New ReportDocument Dim myData As New DataSet Dim conn As New MySqlConnection Dim cmd As New MySqlCommand Dim myAdapter As New MySqlDataAdapter conn.ConnectionString = 'server=127.0.0.1;' _
 & 'uid=root;' _
 & 'pwd=12345;' _
 & 'database=world'
Try
 conn.Open()
 cmd.CommandText = 'SELECT name, population, countrycode FROM city ORDER BY countrycode, name; ' _
 & 'SELECT name, population, code, continent FROM country ORDER BY continent, name'
 cmd.Connection = conn
 myAdapter.SelectCommand = cmd
 myAdapter.Fill(myData)
 myReport.Load('.\world_report.rpt')
 myReport.Database.Tables(0).SetDataSource(myData.Tables(0))
 myReport.Database.Tables(1).SetDataSource(myData.Tables(1))
 myViewer.ReportSource = myReport Catch ex As Exception
 MessageBox.Show(ex.Message, 'Report could not be created', MessageBoxButtons.OK, MessageBoxIcon.Error)
End Try
C# Example
using CrystalDecisions.CrystalReports.Engine;
using System.Data;
using MySql.Data.MySqlClient;
ReportDocument myReport = new ReportDocument();
DataSet myData = new DataSet();
MySql.Data.MySqlClient.MySqlConnection conn;
MySql.Data.MySqlClient.MySqlCommand cmd;
MySql.Data.MySqlClient.MySqlDataAdapter myAdapter;
conn = new MySql.Data.MySqlClient.MySqlConnection();
cmd = new MySql.Data.MySqlClient.MySqlCommand();
myAdapter = new MySql.Data.MySqlClient.MySqlDataAdapter();
conn.ConnectionString = 'server=127.0.0.1;uid=root;' +
 'pwd=12345;database=test;';
try
{
 cmd.CommandText = 'SELECT name, population, countrycode FROM city ORDER ' +
 'BY countrycode, name; SELECT name, population, code, continent FROM ' +
 'country ORDER BY continent, name';
 cmd.Connection = conn;
 myAdapter.SelectCommand = cmd;
 myAdapter.Fill(myData);
 myReport.Load(@'.\world_report.rpt');
 myReport.Database.Tables(0).SetDataSource(myData.Tables(0));
 myReport.Database.Tables(1).SetDataSource(myData.Tables(1));
 myViewer.ReportSource = myReport;
}
catch (MySql.Data.MySqlClient.MySqlException ex)
{
 MessageBox.Show(ex.Message, 'Report could not be created',
 MessageBoxButtons.OK, MessageBoxIcon.Error);
}

It is important to order the SELECT queries in alphabetic order, as this is the order the report will expect its source tables to be in. One SetDataSource statement is needed for each table in the report.

This approach can cause performance problems because Crystal Reports must bind the tables together on the client-side, which will be slower than using a pre-saved data set.

ASP.NET Provider Model

MySQL Connector/Net provides support for the ASP.NET 2.0 provider model. This model enables application developers to focus on the business logic of their application instead of having to recreate such boilerplate items as membership and roles support.

MySQL Connector/Net supplies the following providers:

The following tables show the supported providers, their default provider and the corresponding MariaDB provider.

Membership Provider

Default Provider MySQL Provider
System.Web.Security.SqlMembershipProvider MySql.Web.Security.MySQLMembershipProvider

Role Provider

Default Provider MySQL Provider
System.Web.Security.SqlRoleProvider MySql.Web.Security.MySQLRoleProvider

Profile Provider

Default Provider MySQL Provider
System.Web.Profile.SqlProfileProvider MySql.Web.Profile.MySQLProfileProvider

SessionState Provider

Default Provider MySQL Provider
System.Web.SessionState.InProcSessionStateStore MySql.Web.SessionState.MySqlSessionStateStore
Note

The MariaDB Session State provider uses slightly different capitalization on the class name compared to the other MariaDB providers.

Installing The Providers

The installation of Connector/Net 5.1 or later will install the providers and register them in your machine's .NET configuration file, machine.config. The additional entries created will result in the system.web section appearing similar to the following code: 

<system.web>
 <processModel autoConfig="true" />
 <httpHandlers />
 <membership>
 <providers>
 <add name="AspNetSqlMembershipProvider" type="System.Web.Security.SqlMembershipProvider, System.Web, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a" connectionStringName="LocalSqlServer" enablePasswordRetrieval="false" enablePasswordReset="true" requiresQuestionAndAnswer="true" applicationName="/" requiresUniqueEmail="false" passwordFormat="Hashed" maxInvalidPasswordAttempts="5" minRequiredPasswordLength="7" minRequiredNonalphanumericCharacters='1' passwordAttemptWindow="10" passwordStrengthRegularExpression='' />
 <add name="MySQLMembershipProvider" type="MySql.Web.Security.MySQLMembershipProvider, MySql.Web, Version=6.1.1.0, Culture=neutral, PublicKeyToken=c5687fc88969c44d" connectionStringName="LocalMySqlServer" enablePasswordRetrieval="false" enablePasswordReset="true" requiresQuestionAndAnswer="true" applicationName="/" requiresUniqueEmail="false" passwordFormat="Clear" maxInvalidPasswordAttempts="5" minRequiredPasswordLength="7" minRequiredNonalphanumericCharacters='1' passwordAttemptWindow="10" passwordStrengthRegularExpression='' />
 </providers>
 </membership>
 <profile>
 <providers>
 <add name="AspNetSqlProfileProvider" connectionStringName="LocalSqlServer" applicationName="/" type="System.Web.Profile.SqlProfileProvider, System.Web, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a" />
 <add name="MySQLProfileProvider" type="MySql.Web.Profile.MySQLProfileProvider, MySql.Web, Version=6.1.1.0, Culture=neutral, PublicKeyToken=c5687fc88969c44d" connectionStringName="LocalMySqlServer" applicationName="/" />
 </providers>
 </profile>
 <roleManager>
 <providers>
 <add name="AspNetSqlRoleProvider" connectionStringName="LocalSqlServer" applicationName="/" type="System.Web.Security.SqlRoleProvider, System.Web, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a" />
 <add name="AspNetWindowsTokenRoleProvider" applicationName="/" type="System.Web.Security.WindowsTokenRoleProvider, System.Web, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a" />
 <add name="MySQLRoleProvider" type="MySql.Web.Security.MySQLRoleProvider, MySql.Web, Version=6.1.1.0, Culture=neutral, PublicKeyToken=c5687fc88969c44d" connectionStringName="LocalMySqlServer" applicationName="/" />
 </providers>
 </roleManager>
</system.web>

Each provider type can have multiple provider implementations. The default provider can also be set here using the defaultProvider attribute, but usually this is set in the web.config file either manually or by using the ASP.NET configuration tool.

At time of writing, the MySqlSessionStateStore is not added to machine.config at install time, and so add the following: 

<sessionState>
 <providers>
 <add name="MySqlSessionStateStore" type="MySql.Web.SessionState.MySqlSessionStateStore, MySql.Web, Version=6.1.1.0, Culture=neutral, PublicKeyToken=c5687fc88969c44d" connectionStringName="LocalMySqlServer" applicationName="/" />
 </providers>
</sessionState>

The SessionState Provider uses the customProvider attribute, rather than defaultProvider, to set the provider as the default. A typical web.config file might contain: 

 <system.web>
 <membership defaultProvider="MySQLMembershipProvider" />
 <roleManager defaultProvider="MySQLRoleProvider" />
 <profile defaultProvider="MySQLProfileProvider" />
 <sessionState customProvider="MySqlSessionStateStore" />
 <compilation debug="false">
 ...

This sets the MariaDB Providers as the defaults to be used in this web application.

The providers are implemented in the file mysql.web.dll and this file can be found in your MariaDB Connector/Net installation folder. There is no need to run any type of SQL script to set up the database schema, as the providers create and maintain the proper schema automatically.

Using The Providers

The easiest way to start using the providers is to use the ASP.NET configuration tool that is available on the Solution Explorer toolbar when you have a website project loaded.

In the web pages that open, you can select the MariaDB membership and roles providers by picking a custom provider for each area.

When the provider is installed, it creates a dummy connection string named LocalMySqlServer. Although this has to be done so that the provider will work in the ASP.NET configuration tool, you override this connection string in your web.config file. You do this by first removing the dummy connection string and then adding in the proper one, as shown in the following example: 

<connectionStrings>
 <remove name="LocalMySqlServer"/>
 <add name="LocalMySqlServer" connectionString="server=xxx;uid=xxx;pwd=xxx;database=xxx;"/>
</connectionStrings>

Note the database to connect to must be specified.

Rather than manually editing configuration files, consider using the MariaDB Website Configuration tool to configure your desired provider setup. From MariaDB Connector/Net 6.1.1 onwards, all providers can be selected and configured from this wizard. The tool modifies your website.config file to the desired configuration. A tutorial on doing this is available in the following section , "MySQL Website Configuration Tool".

A tutorial demonstrating how to use the Membership and Role Providers can be found in the following section , "Tutorial: MariaDB Connector/Net ASP.NET Membership and Role Provider".

Deployment

To use the providers on a production server, distribute the MySql.Data and the MySql.Web assemblies, and either register them in the remote systems Global Assembly Cache or keep them in your application's bin/ directory.

Working with Partial Trust

.NET applications operate under a given trust level. Normal desktop applications operate under full trust, while web applications that are hosted in shared environments are normally run under the partial trust level (also known as "medium trust"). Some hosting providers host shared applications in their own app pools and allow the application to run under full trust, but this configuration is relatively rare. The Connector/Net support for partial trust has improved over time to simplify the configuration and deployment process for hosting providers.

6.5.1 and Above: Full Support for Partial Trust

Connector/Net 6.5 fully enables our provider to run in a partial trust environment when the library is installed in the Global Assembly Cache (GAC). The new MySqlClientPermission class, derived from the .NET DBDataPermission class, helps to simplify the permission setup.

Starting from 6.5 you can use the Connector/Net library inside any medium-trust level environment without any issue.

The following list shows steps and code fragments needed to run a Connector/Net application in a partial trust environment. For illustration purposes, we use the Pipe Connections protocol in this example.

  1. Configure the MariaDB server to accept pipe connections, by adding the --enable-named-pipe option on the command line. If you need more information about this, see , "Installing MariaDB on Microsoft Windows".
  2. Confirm that the hosting provider has installed the Connector/Net library (MySql.Data.dll) in the GAC.
  3. Optionally, the hosting provider can avoid granting permissions globally by using the new MySqlClientPermission class in the trust policies. (The alternative is to globally enable the permissions System.Net.SocketPermission, System.Security.Permissions.ReflectionPermission, System.Net.DnsPermission, and System.Security.Permissions.SecurityPermission.)
  4. Create a simple web application using Visual Studio 2010.
  5. Add the reference in your application for the MySql.Data.MySqlClient library.
  6. Edit your web.config file so that your application runs using a Medium trust level: 
     <system.web>
 <trust level="Medium"/>
 </system.web>
  7. Add the MySql.Data.MySqlClient namespace to your server-code page.
  8. Define the connection string: 
    MySqlConnectionStringBuilder myconnString = new MySqlConnectionStringBuilder('server=localhost;User Id=root;database=test;' );
 myconnString.PipeName = 'MySQL55';
 myconnString.ConnectionProtocol = MySqlConnectionProtocol.Pipe;
  9. Define the MySqlConnection to use: 
    MySqlConnection myconn = new MySqlConnection(myconnString.ConnectionString);
myconn.Open();
  10. Retrieve some data from your tables: 
    MySqlCommand cmd = new MySqlCommand('Select * from products', myconn);
MySqlDataAdapter da = new MySqlDataAdapter(cmd);
DataSet1 tds = new DataSet1();
da.Fill(tds, tds.Tables[0].TableName);
GridView1.DataSource = tds;
GridView1.DataBind();
myconn.Close()
  11. Run the program. It should execute successfully, without requiring any special code or encountering any security problems.
5.0.8 / 5.1.3 and Above: Partial Trust Requires Socket Permissions

Starting with these versions, Connector/Net can be used under partial trust hosting that has been modified to allow the use of sockets for communication. By default, partial trust does not include SocketPermission. Connector/Net uses sockets to talk with the MariaDB server so the hosting provider must create a new trust level that is an exact clone of partial trust but that has the following permissions added:

Prior to 5.0.8 / 5.1.3: Partial Trust Not Supported

Connector/Net versions prior to 5.0.8 and 5.1.3 were not compatible with partial trust hosting.

Connector/Net Connection String Options Reference

For usage information about connection strings, see , "Creating a Connector/Net Connection String". The first table list options that apply generally to all server configurations. The options related to systems using a connection pool are split into a separate table.

General Options

Name Default Description
Allow Batch, AllowBatch true When true, multiple SQL statements can be sent with one command execution. Note: starting with MariaDB, batch statements should be separated by the server-defined separator character. Commands sent to earlier versions of MariaDB should be separated with ';'.
Allow User Variables, AllowUserVariables false Setting this to true indicates that the provider expects user variables in the SQL. This option was added in Connector/Net version 5.2.2.
Allow Zero Datetime, AllowZeroDateTime false If set to True, MySqlDataReader.GetValue() returns a MySqlDateTime object for date or datetime columns that have disallowed values, such as zero datetime values, and a System.DateTime object for valid values. If set to False (the default setting) it will cause a System.DateTime object to be returned for all legal values and an exception to be thrown for disallowed values, such as zero datetime values.
Auto Enlist, AutoEnlist true If AutoEnlist is set to true, which is the default, a connection opened using TransactionScope participates in this scope, it commits when the scope commits and rolls back if TransactionScope does not commit. However, this feature is considered security sensitive and therefore cannot be used in a medium trust environment.
BlobAsUTF8ExcludePattern null A POSIX-style regular expression that matches the names of BLOB columns that do not contain UTF-8 character data. See , "Character Set Considerations for Connector/Net" for usage details.
BlobAsUTF8IncludePattern null A POSIX-style regular expression that matches the names of BLOB columns containing UTF-8 character data. See , "Character Set Considerations for Connector/Net" for usage details.
Certificate File, CertificateFile null This option specifies the path to a certificate file in PKCS #12 format (.pfx). For an example of usage, see , "Tutorial: Using SSL with MariaDB Connector/Net". Was introduced with 6.2.1.
Certificate Password, CertificatePassword null Specifies a password that is used in conjunction with a certificate specified using the option CertificateFile. For an example of usage, see , "Tutorial: Using SSL with MariaDB Connector/Net". Was introduced with 6.2.1.
Certificate Store Location, CertificateStoreLocation null Enables you to access a certificate held in a personal store, rather than use a certificate file and password combination. For an example of usage, see , "Tutorial: Using SSL with MariaDB Connector/Net". Was introduced with 6.2.1.
Certificate Thumbprint, CertificateThumbprint null Specifies a certificate thumbprint to ensure correct identification of a certificate contained within a personal store. For an example of usage, see , "Tutorial: Using SSL with MariaDB Connector/Net". Was introduced with 6.2.1.
CharSet, Character Set, CharacterSet Specifies the character set that should be used to encode all queries sent to the server. Resultsets are still returned in the character set of the result data.
Check Parameters, CheckParameters true Indicates if stored routine parameters should be checked against the server.
Command Interceptors, CommandInterceptors The list of interceptors that can intercept SQL command operations.
Connect Timeout, Connection Timeout, ConnectionTimeout 15 The length of time (in seconds) to wait for a connection to the server before terminating the attempt and generating an error.
Convert Zero Datetime, ConvertZeroDateTime false True to have MySqlDataReader.GetValue() and MySqlDataReader.GetDateTime() return DateTime.MinValue for date or datetime columns that have disallowed values.
Default Command Timeout, DefaultCommandTimeout 30 Sets the default value of the command timeout to be used. This does not supercede the individual command timeout property on an individual command object. If you set the command timeout property, that will be used. This option was added in Connector/Net 5.1.4
Default Table Cache Age, DefaultTableCacheAge 60 Specifies how long a TableDirect result should be cached, in seconds. For usage information about table caching, see , "Using Connector/Net with Table Caching". This option was added in Connector/Net 6.4.
Encrypt, UseSSL false For Connector/Net 5.0.3 and later, when true, SSL encryption is used for all data sent between the client and server if the server has a certificate installed. Recognized values are true, false, yes, and no. In versions before 5.0.3, this option had no effect. From version 6.2.1, this option is deprecated and is replaced by SSL Mode. The option still works if used. If this option is set to true, it is equivalent to SSL Mode = Preferred.
Exception Interceptors, ExceptionInterceptors The list of interceptors that can triage thrown MySqlException exceptions.
Functions Return String, FunctionsReturnString false Causes the connector to return binary/varbinary values as strings, if they do not have a tablename in the metadata.
Host, Server, Data Source, DataSource, Address, Addr, Network Address localhost The name or network address of the instance of MariaDB to which to connect. Multiple hosts can be specified separated by commas. This can be useful where multiple MariaDB servers are configured for replication and you are not concerned about the precise server you are connecting to. No attempt is made by the provider to synchronize writes to the database, so take care when using this option. In Unix environment with Mono, this can be a fully qualified path to a MariaDB socket file. With this configuration, the Unix socket will be used instead of the TCP/IP socket. Currently, only a single socket name can be given, so accessing MariaDB in a replicated environment using Unix sockets is not currently supported.
Ignore Prepare, IgnorePrepare true When true, instructs the provider to ignore any calls to MySqlCommand.Prepare(). This option is provided to prevent issues with corruption of the statements when used with server-side prepared statements. If you use server-side prepare statements, set this option to false. This option was added in Connector/Net 5.0.3 and Connector/Net 1.0.9.
Initial Catalog, Database mysql The case-sensitive name of the database to use initially.
Interactive, Interactive Session, InteractiveSession false If set to true, the client is interactive. An interactive client is one where the server variable CLIENT_INTERACTIVE is set. If an interactive client is set, the wait_timeout variable is set to the value of interactive_timeout. The client will then timeout after this period of inactivity. More details can be found in the server manual , "Server System Variables".
Integrated Security, IntegratedSecurity no Use Windows authentication when connecting to server. By default, it is turned off. To enable, specify a value of yes. (You can also use the value sspi as an alternative to yes.) For details, see , "Using the Windows Native Authentication Plugin". This option was introduced in Connector/Net 6.4.4.
Keep Alive, Keepalive 0 For TCP connections, idle connection time measured in seconds, before the first keepalive packet is sent. A value of 0 indicates that keepalive is not used.
Logging false When true, various pieces of information is output to any configured TraceListeners. See , "Using the MariaDB Connector/Net Trace Source Object" for further details.
Old Guids, OldGuids false This option was introduced in Connector/Net 6.1.1. The backend representation of a GUID type was changed from BINARY(16) to CHAR(36). This was done to allow developers to use the server function UUID() to populate a GUID table - UUID() generates a 36-character string. Developers of older applications can add 'Old Guids=true' to the connection string to use a GUID of data type BINARY(16).
Old Syntax, OldSyntax, Use Old Syntax, UseOldSyntax false This option was deprecated in Connector/Net 5.2.2. All code should now be written using the '@' symbol as the parameter marker.
Password, pwd The password for the MariaDB account being used.
Persist Security Info, PersistSecurityInfo false When set to false or no (strongly recommended), security-sensitive information, such as the password, is not returned as part of the connection if the connection is open or has ever been in an open state. Resetting the connection string resets all connection string values, including the password. Recognized values are true, false, yes, and no.
Pipe Name, Pipe, PipeName mysql When set to the name of a named pipe, the MySqlConnection will attempt to connect to MariaDB on that named pipe. This setting only applies to the Windows platform.
Port 3306 The port MariaDB is using to listen for connections. This value is ignored if Unix socket is used.
Procedure Cache Size, ProcedureCacheSize, procedure cache, procedurecache 25 Sets the size of the stored procedure cache. By default, Connector/Net stores the metadata (input/output data types) about the last 25 stored procedures used. To disable the stored procedure cache, set the value to zero (0). This option was added in Connector/Net 5.0.2 and Connector/Net 1.0.9.
Protocol, Connection Protocol, ConnectionProtocol socket Specifies the type of connection to make to the server. Values can be: socket or tcp for a socket connection, pipe for a named pipe connection, unix for a Unix socket connection, memory to use MariaDB shared memory.
Replication false Indicates if this connection is to use replicated servers.
Respect Binary Flags, RespectBinaryFlags true Setting this option to false means that Connector/Net ignores a column's binary flags as set by the server. This option was added in Connector/Net version 5.1.3.
Shared Memory Name, SharedMemoryName MYSQL The name of the shared memory object to use for communication if the connection protocol is set to memory.
Sql Server Mode, sqlservermode false Allow SQL Server syntax. When set to true, enables Connector/Net to support square brackets around symbols instead of backticks. This enables Visual Studio wizards that bracket symbols with [] to work with Connector/Net. This option incurs a performance hit, so should only be used if necessary. This option was added in version 6.3.1.
SSL Mode, SslMode None This option has the following values:
  • None - do not use SSL.
  • Preferred - use SSL if the server supports it, but allow connection in all cases.
  • Required - Always use SSL. Deny connection if server does not support SSL.
  • VerifyCA - Always use SSL. Validate the CA but tolerate name mismatch.
  • VerifyFull - Always use SSL. Fail if the host name is not correct.

This option was introduced in MariaDB Connector/Net 6.2.1.

Table Cache, tablecache, tablecaching false Enables or disables caching of TableDirect commands. A value of true enables the cache while false disables it. For usage information about table caching, see , "Using Connector/Net with Table Caching". This option was added in Connector/Net 6.4.
Treat BLOBs as UTF8, TreatBlobsAsUTF8 false
Treat Tiny As Boolean, TreatTinyAsBoolean true Setting this value to false indicates that TINYINT(1) will be treated as an INT. See , "Numeric Type Overview" for a further explanation of the TINYINT and BOOL data types.
Use Affected Rows, UseAffectedRows false When true the connection will report changed rows instead of found rows. This option was added in Connector/Net version 5.2.6.
Use Procedure Bodies, UseProcedureBodies, procedure bodies true When set to true, the default value, MariaDB Connector/Net expects the body of the procedure to be viewable. This enables it to determine the parameter types and order. Set the option to false when the user connecting to the database does not have the SELECT privileges for the mysql.proc (stored procedures) table, or cannot view INFORMATION_SCHEMA.ROUTINES. In this case, MariaDB Connector/Net cannot determine the types and order of the parameters, and must be alerted to this fact by setting this option to false. When set to false, MariaDB Connector/Net does not rely on this information being available when the procedure is called. Because MariaDB Connector/Net will not be able to determine this information, explicitly set the types of all the parameters before the call and add the parameters to the command in the same order as they appear in the procedure definition. This option was added in MariaDB Connector/Net 5.0.4 and MariaDB Connector/Net 1.0.10.
User Id, UserID, Username, Uid, User name, User The MariaDB login account being used.
Compress, Use Compression, UseCompression false Setting this option to true enables compression of packets exchanged between the client and the server. This exchange is defined by the MariaDB client/server protocol.

Compression is used if both client and server support ZLIB compression, and the client has requested compression using this option.

A compressed packet header is: packet length (3 bytes), packet number (1 byte), and Uncompressed Packet Length (3 bytes). The Uncompressed Packet Length is the number of bytes in the original, uncompressed packet. If this is zero, the data in this packet has not been compressed. When the compression protocol is in use, either the client or the server may compress packets. However, compression will not occur if the compressed length is greater than the original length. Thus, some packets will contain compressed data while other packets will not.

Use Usage Advisor, Usage Advisor, UseUsageAdvisor false Logs inefficient database operations.
Use Performance Monitor, UsePerformanceMonitor, userperfmon, perfmon false Indicates that performance counters should be updated during execution.

Connection Pooling Options

The following table lists the valid names for options related to connection pooling within the ConnectionString. For more information about connection pooling, see , "Using Connector/Net with Connection Pooling".

Name Default Description
Cache Server Properties, CacheServerProperties false Specifies whether server variable settings are updated by a SHOW VARIABLES command each time a pooled connection is returned. Enabling this setting speeds up connections in a connection pool environment. Your application will not be informed of any changes to configuration variables made by other connections. This option was added in Connector/Net 6.3.
Connection Lifetime, ConnectionLifeTime 0 When a connection is returned to the pool, its creation time is compared with the current time, and the connection is destroyed if that time span (in seconds) exceeds the value specified by Connection Lifetime. This is useful in clustered configurations to force load balancing between a running server and a server just brought online. A value of zero (0) causes pooled connections to have the maximum connection timeout.
Connection Reset, ConnectionReset false If true, the connection state will be reset when it is retrieved from the pool. The default value of false avoids making an additional server round trip when obtaining a connection, but the connection state is not reset.
Maximum Pool Size, Max Pool Size, maximumpoolsize 100 The maximum number of connections allowed in the pool.
Minimum Pool Size, Min Pool Size, MinimumPoolSize 0 The minimum number of connections allowed in the pool.
Pooling true When true, the MySqlConnection object is drawn from the appropriate pool, or if necessary, is created and added to the appropriate pool. Recognized values are true, false, yes, and no.

Connector/Net API Reference

MySql.Data.MySqlClient
MySql.Data.Types

This section of the manual contains a complete reference to the Connector/Net ADO.NET component, automatically generated from the embedded documentation.

MySql.Data.MySqlClient

MySql.Data.MySqlClientHierarchy
BaseCommandInterceptor
BaseExceptionInterceptor
MySqlCommand Class
MySqlCommandBuilder Class
MySqlException Class
MySqlHelper Class
MySqlErrorCode Enumeration

Namespace hierarchy

Classes

Class Description
BaseCommandInterceptor Provides a means of enhancing or replacing SQL commands through the connection string rather than recompiling.
BaseExceptionInterceptor Provides a means of enabling and disabling exception handling through the connection string rather than recompiling.
MySqlClientPermission Derived from the .NET DBDataPermission class. For usage information, see , "Working with Partial Trust".
MySqlCommand
MySqlCommandBuilder
MySqlConnection
MySqlDataAdapter
MySqlDataReader Provides a means of reading a forward-only stream of rows from a MariaDB database. This class cannot be inherited.
MySqlError Collection of error codes that can be returned by the server
MySqlException The exception that is thrown when MariaDB returns an error. This class cannot be inherited.
MySqlHelper Helper class that makes it easier to work with the provider.
MySqlInfoMessageEventArgs Provides data for the InfoMessage event. This class cannot be inherited.
MySqlParameter Represents a parameter to a MySqlCommand, and optionally, its mapping to DataSetcolumns. This class cannot be inherited.
MySqlParameterCollection Represents a collection of parameters relevant to a MySqlCommand as well as their respective mappings to columns in a DataSet. This class cannot be inherited.
MySqlRowUpdatedEventArgs Provides data for the RowUpdated event. This class cannot be inherited.
MySqlRowUpdatingEventArgs Provides data for the RowUpdating event. This class cannot be inherited.
MySqlTransaction

Delegates

Delegate Description
MySqlInfoMessageEventHandler Represents the method that will handle the InfoMessage event of a MySqlConnection.
MySqlRowUpdatedEventHandler Represents the method that will handle the RowUpdatedevent of a MySqlDataAdapter.
MySqlRowUpdatingEventHandler Represents the method that will handle the RowUpdatingevent of a MySqlDataAdapter.

Enumerations

Enumeration Description
MySqlDbType Specifies MySQL-specific data type of a field, property, for use in a MySqlParameter.
MySqlErrorCode
MySql.Data.MySqlClientHierarchy

See Also

MySql.Data.MySqlClient Namespace

BaseCommandInterceptor

The BaseCommandInterceptor class has these methods that you can override: 

public virtual bool ExecuteScalar(string sql, ref object returnValue);
public virtual bool ExecuteNonQuery(string sql, ref int returnValue);
public virtual bool ExecuteReader(string sql, CommandBehavior behavior, ref MySqlDataReader returnValue);
public virtual void Init(MySqlConnection connection);

If your interceptor overrides one of the Execute... methods, set the returnValue output parameter and return true if you handled the event, or false if you did not handle the event. The SQL command is processed normally only when all command interceptors return false.

The connection passed to the Init method is the connection that is attached to this interceptor.

For full usage and examples, see , "Using the Connector/Net Interceptor Classes".

BaseExceptionInterceptor

You develop an exception interceptor first by creating a subclass of the BaseExceptionInterceptor class. You must override the InterceptException() method. You can also override the Init() method to do some one-time initialization.

Each exception interceptor has 2 methods: 

public abstract Exception InterceptException(Exception exception,
 MySqlConnection connection);
public virtual void Init(MySqlConnection connection);

The connection passed to Init() is the connection that is attached to this interceptor.

Each interceptor is required to override InterceptException and return an exception. It can return the exception it is given, or it can wrap it in a new exception. We currently do not offer the ability to suppress the exception.

For full usage and examples, see , "Using the Connector/Net Interceptor Classes".

MySqlCommand Class
MySqlCommand Members

For a list of all members of this type, see MySqlCommand Members.

Syntax: Visual Basic

NotInheritable Public Class MySqlCommand_
 Inherits Component_
 Implements IDbCommand, ICloneable

Syntax: C#

public sealed class MySqlCommand : Component, IDbCommand, ICloneable

Thread Safety

Public static (Shared in Visual Basic) members of this type are safe for multithreaded operations. Instance members are not guaranteed to be thread-safe.

Requirements

Namespace: MySql.Data.MySqlClient

Assembly: MySql.Data (in MySql.Data.dll)

See Also

MySqlCommand Members, MySql.Data.MySqlClient Namespace

MySqlCommand Members
MySqlCommand Constructor
CommandText Property
CommandTimeout Property
CommandType Property
Connection Property
IsPrepared Property
Parameters Property
Transaction Property
UpdatedRowSource Property
MySqlCommand.Cancel Method
MySqlCommand.CreateParameter Method
MySqlCommand.ExecuteNonQuery Method
ExecuteReader Method
MySqlCommand.ExecuteScalar Method
MySqlCommand.Prepare Method

MySqlCommand overview

Public Instance Constructors

MySqlCommand Overloaded. Initializes a new instance of the MySqlCommand class.

Public Instance Properties

CommandText
CommandTimeout
CommandType
Connection
Container (inherited from Component) Gets the IContainer that contains the Component.
IsPrepared
Parameters
Site (inherited from Component) Gets or sets the ISite of the Component.
Transaction
UpdatedRowSource

Public Instance Methods

Cancel Attempts to cancel the execution of a MySqlCommand. This operation is not supported.
CreateObjRef (inherited from MarshalByRefObject) Creates an object that contains all the relevant information required to generate a proxy used to communicate with a remote object.
CreateParameter Creates a new instance of a MySqlParameter object.
Dispose (inherited from Component) Releases all resources used by the Component.
Equals (inherited from Object) Determines whether the specified Object is equal to the current Object.
ExecuteNonQuery
ExecuteReader Overloaded.
ExecuteScalar
GetHashCode (inherited from Object) Serves as a hash function for a particular type. GetHashCode is suitable for use in hashing algorithms and data structures like a hash table.
GetLifetimeService (inherited from MarshalByRefObject) Retrieves the current lifetime service object that controls the lifetime policy for this instance.
GetType (inherited from Object) Gets the Type of the current instance.
InitializeLifetimeService (inherited from MarshalByRefObject) Obtains a lifetime service object to control the lifetime policy for this instance.
Prepare
ToString (inherited from Component) Returns a String containing the name of the Component, if any. This method should not be overridden.

Public Instance Events

Disposed (inherited from Component) Adds an event handler to listen to the Disposed event on the component.

See Also

MySqlCommand Class, MySql.Data.MySqlClient Namespace

MySqlCommand Constructor
MySqlCommand Constructor ()
MySqlCommand Constructor (String)
MySqlCommand Constructor
MySqlCommand Constructor

Initializes a new instance of the MySqlCommand class.

Overload List

Initializes a new instance of the MySqlCommand class.

See Also

MySqlCommand Class, MySql.Data.MySqlClient Namespace

MySqlCommand Constructor ()

Initializes a new instance of the MySqlCommand class.

Syntax: Visual Basic

Overloads Public Sub New()

Syntax: C#

public MySqlCommand();

See Also

MySqlCommand Class, MySql.Data.MySqlClient Namespace, MySqlCommand Constructor Overload List

MySqlCommand Constructor (String)

Syntax: Visual Basic

Overloads Public Sub New( _
 ByVal cmdText As String _
)

Syntax: C#

public MySqlCommand(
stringcmdText
);

See Also

MySqlCommand Class, MySql.Data.MySqlClient Namespace, MySqlCommand Constructor Overload List

MySqlCommand Constructor
MySqlConnection Class

Syntax: Visual Basic

Overloads Public Sub New( _
 ByVal cmdText As String, _
 ByVal connection As MySqlConnection _
)

Syntax: C#

public MySqlCommand(
stringcmdText,
MySqlConnectionconnection
);

See Also

MySqlCommand Class, MySql.Data.MySqlClient Namespace, MySqlCommand Constructor Overload List

MySqlConnection Class
MySqlConnection Members

For a list of all members of this type, see MySqlConnection Members .

Syntax: Visual Basic

NotInheritable Public Class MySqlConnection_
 Inherits Component_
 Implements IDbConnection, ICloneable

Syntax: C#

public sealed class MySqlConnection : Component, IDbConnection, ICloneable

Thread Safety

Public static (Shared in Visual Basic) members of this type are safe for multithreaded operations. Instance members are not guaranteed to be thread-safe.

Requirements

Namespace: MySql.Data.MySqlClient

Assembly: MySql.Data (in MySql.Data.dll)

See Also

MySqlConnection Members, MySql.Data.MySqlClient Namespace

MySqlConnection Members

MySqlConnection overview

Public Instance Constructors

MySqlConnection Overloaded. Initializes a new instance of the MySqlConnection class.

Public Instance Properties

ConnectionString
ConnectionTimeout
Container (inherited from Component) Gets the IContainer that contains the Component.
Database
DataSource Gets the name of the MariaDB server to which to connect.
ServerThread Returns the ID of the server thread this connection is executing on.
ServerVersion
Site (inherited from Component) Gets or sets the ISite of the Component.
State
UseCompression Indicates if this connection should use compression when communicating with the server.

Public Instance Methods

BeginTransaction Overloaded.
ChangeDatabase
Close
CreateCommand
CreateObjRef (inherited from MarshalByRefObject) Creates an object that contains all the relevant information required to generate a proxy used to communicate with a remote object.
Dispose (inherited from Component) Releases all resources used by the Component.
Equals (inherited from Object) Determines whether the specified Object is equal to the current Object.
GetHashCode (inherited from Object) Serves as a hash function for a particular type. GetHashCode is suitable for use in hashing algorithms and data structures like a hash table.
GetLifetimeService (inherited from MarshalByRefObject) Retrieves the current lifetime service object that controls the lifetime policy for this instance.
GetType (inherited from Object) Gets the Type of the current instance.
InitializeLifetimeService (inherited from MarshalByRefObject) Obtains a lifetime service object to control the lifetime policy for this instance.
Open
Ping Ping
ToString (inherited from Component) Returns a String containing the name of the Component, if any. This method should not be overridden.

Public Instance Events

Disposed (inherited from Component) Adds an event handler to listen to the Disposed event on the component.
InfoMessage
StateChange

See Also

MySqlConnection Class, MySql.Data.MySqlClient Namespace

MySqlConnection Constructor

Initializes a new instance of the MySqlConnection class.

Overload List

Initializes a new instance of the MySqlConnection class.

See Also

MySqlConnection Class, MySql.Data.MySqlClient Namespace

MySqlConnection Constructor

Initializes a new instance of the MySqlConnection class.

Syntax: Visual Basic

Overloads Public Sub New()

Syntax: C#

public MySqlConnection();

See Also

MySqlConnection Class, MySql.Data.MySqlClient Namespace, MySqlConnection Constructor Overload List

MySqlConnection Constructor

Syntax: Visual Basic

Overloads Public Sub New( _
 ByVal connectionString As String _
)

Syntax: C#

public MySqlConnection(
stringconnectionString
);

See Also

MySqlConnection Class, MySql.Data.MySqlClient Namespace, MySqlConnection Constructor Overload List

ConnectionString Property

Syntax: Visual Basic

NotOverridable Public Property ConnectionString As String _
_
 Implements IDbConnection.ConnectionString

Syntax: C#

public string ConnectionString {get; set;}

Implements

IDbConnection.ConnectionString

See Also

MySqlConnection Class, MySql.Data.MySqlClient Namespace

ConnectionTimeout Property

Syntax: Visual Basic

NotOverridable Public ReadOnly Property ConnectionTimeout As Integer _
_
 Implements IDbConnection.ConnectionTimeout

Syntax: C#

public int ConnectionTimeout {get;}

Implements

IDbConnection.ConnectionTimeout

See Also

MySqlConnection Class, MySql.Data.MySqlClient Namespace

Database Property

Syntax: Visual Basic

NotOverridable Public ReadOnly Property Database As String _
_
 Implements IDbConnection.Database

Syntax: C#

public string Database {get;}

Implements

IDbConnection.Database

See Also

MySqlConnection Class, MySql.Data.MySqlClient Namespace

DataSource Property

Gets the name of the MariaDB server to which to connect.

Syntax: Visual Basic

Public ReadOnly Property DataSource As String

Syntax: C#

public string DataSource {get;}

See Also

MySqlConnection Class, MySql.Data.MySqlClient Namespace

ServerThread Property

Returns the ID of the server thread this connection is executing on

Syntax: Visual Basic

Public ReadOnly Property ServerThread As Integer

Syntax: C#

public int ServerThread {get;}

See Also

MySqlConnection Class, MySql.Data.MySqlClient Namespace

ServerVersion Property

Syntax: Visual Basic

Public ReadOnly Property ServerVersion As String

Syntax: C#

public string ServerVersion {get;}

See Also

MySqlConnection Class, MySql.Data.MySqlClient Namespace

State Property

Syntax: Visual Basic

NotOverridable Public ReadOnly Property State As ConnectionState _
_
 Implements IDbConnection.State

Syntax: C#

public System.Data.ConnectionState State {get;}

Implements

IDbConnection.State

See Also

MySqlConnection Class, MySql.Data.MySqlClient Namespace

UseCompression Property

Indicates if this connection should use compression when communicating with the server.

Syntax: Visual Basic

Public ReadOnly Property UseCompression As Boolean

Syntax: C#

public bool UseCompression {get;}

See Also

MySqlConnection Class, MySql.Data.MySqlClient Namespace

BeginTransaction Method

Overload List

See Also

MySqlConnection Class, MySql.Data.MySqlClient Namespace

MySqlConnection.BeginTransaction Method

Syntax: Visual Basic

Overloads Public Function BeginTransaction() As MySqlTransaction

Syntax: C#

public MySqlTransaction BeginTransaction();

See Also

MySqlConnection Class, MySql.Data.MySqlClient Namespace, MySqlConnection.BeginTransaction Overload List

MySqlTransaction Class

For a list of all members of this type, see MySqlTransaction Members .

Syntax: Visual Basic

NotInheritable Public Class MySqlTransaction_
 Implements IDbTransaction, IDisposable

Syntax: C#

public sealed class MySqlTransaction : IDbTransaction, IDisposable

Thread Safety

Public static (Shared in Visual Basic) members of this type are safe for multithreaded operations. Instance members are not guaranteed to be thread-safe.

Requirements

Namespace: MySql.Data.MySqlClient

Assembly: MySql.Data (in MySql.Data.dll)

See Also

MySqlTransaction Members, MySql.Data.MySqlClient Namespace

MySqlTransaction Members

MySqlTransaction overview

Public Instance Properties

Connection Gets the MySqlConnection object associated with the transaction, or a null reference (Nothing in Visual Basic) if the transaction is no longer valid.
IsolationLevel Specifies the IsolationLevel for this transaction.

Public Instance Methods

Commit
Equals (inherited from Object) Determines whether the specified Object is equal to the current Object.
GetHashCode (inherited from Object) Serves as a hash function for a particular type. GetHashCode is suitable for use in hashing algorithms and data structures like a hash table.
GetType (inherited from Object) Gets the Type of the current instance.
Rollback
ToString (inherited from Object) Returns a String that represents the current Object.

See Also

MySqlTransaction Class, MySql.Data.MySqlClient Namespace

Connection Property

Gets the MySqlConnection object associated with the transaction, or a null reference (Nothing in Visual Basic) if the transaction is no longer valid.

Syntax: Visual Basic

Public ReadOnly Property Connection As MySqlConnection

Syntax: C#

public MySqlConnection Connection {get;}

Property Value

The MySqlConnection object associated with this transaction.

Remarks

A single application may have multiple database connections, each with zero or more transactions. This property enables you to determine the connection object associated with a particular transaction created by BeginTransaction.

See Also

MySqlTransaction Class, MySql.Data.MySqlClient Namespace

IsolationLevel Property

Specifies the IsolationLevel for this transaction.

Syntax: Visual Basic

NotOverridable Public ReadOnly Property IsolationLevel As IsolationLevel _
_
 Implements IDbTransaction.IsolationLevel

Syntax: C#

public System.Data.IsolationLevel IsolationLevel {get;}

Property Value

The IsolationLevel for this transaction. The default is ReadCommitted.

Implements

IDbTransaction.IsolationLevel

Remarks

Parallel transactions are not supported. Therefore, the IsolationLevel applies to the entire transaction.

See Also

MySqlTransaction Class, MySql.Data.MySqlClient Namespace

MySqlTransaction.Commit Method

Syntax: Visual Basic

NotOverridable Public Sub Commit() _
_
 Implements IDbTransaction.Commit

Syntax: C#

public void Commit();

Implements

IDbTransaction.Commit

See Also

MySqlTransaction Class, MySql.Data.MySqlClient Namespace

MySqlTransaction.Rollback Method

Syntax: Visual Basic

NotOverridable Public Sub Rollback() _
_
 Implements IDbTransaction.Rollback

Syntax: C#

public void Rollback();

Implements

IDbTransaction.Rollback

See Also

MySqlTransaction Class, MySql.Data.MySqlClient Namespace

MySqlConnection.BeginTransaction Method

Syntax: Visual Basic

Overloads Public Function BeginTransaction( _
 ByVal iso As IsolationLevel _
) As MySqlTransaction

Syntax: C#

public MySqlTransaction BeginTransaction(
IsolationLeveliso
);

See Also

MySqlConnection Class, MySql.Data.MySqlClient Namespace, MySqlConnection.BeginTransaction Overload List

MySqlConnection.ChangeDatabase Method

Syntax: Visual Basic

NotOverridable Public Sub ChangeDatabase( _
 ByVal databaseName As String _
) _
_
 Implements IDbConnection.ChangeDatabase

Syntax: C#

public void ChangeDatabase(
stringdatabaseName
);

Implements

IDbConnection.ChangeDatabase

See Also

MySqlConnection Class, MySql.Data.MySqlClient Namespace

MySqlConnection.Close Method

Syntax: Visual Basic

NotOverridable Public Sub Close() _
_
 Implements IDbConnection.Close

Syntax: C#

public void Close();

Implements

IDbConnection.Close

See Also

MySqlConnection Class, MySql.Data.MySqlClient Namespace

MySqlConnection.CreateCommand Method

Syntax: Visual Basic

Public Function CreateCommand() As MySqlCommand

Syntax: C#

public MySqlCommand CreateCommand();

See Also

MySqlConnection Class, MySql.Data.MySqlClient Namespace

MySqlConnection.Open Method

Syntax: Visual Basic

NotOverridable Public Sub Open() _
_
 Implements IDbConnection.Open

Syntax: C#

public void Open();

Implements

IDbConnection.Open

See Also

MySqlConnection Class, MySql.Data.MySqlClient Namespace

MySqlConnection.Ping Method

Ping

Syntax: Visual Basic

Public Function Ping() As Boolean

Syntax: C#

public bool Ping();

Return Value

See Also

MySqlConnection Class, MySql.Data.MySqlClient Namespace

MySqlConnection.InfoMessage Event

Syntax: Visual Basic

Public Event InfoMessage As MySqlInfoMessageEventHandler

Syntax: C#

public event MySqlInfoMessageEventHandler InfoMessage;

See Also

MySqlConnection Class, MySql.Data.MySqlClient Namespace

MySqlInfoMessageEventHandler Delegate

Represents the method that will handle the InfoMessage event of a MySqlConnection.

Syntax: Visual Basic

Public Delegate Sub MySqlInfoMessageEventHandler( _
 ByVal sender As Object, _
 ByVal args As MySqlInfoMessageEventArgs _
)

Syntax: C#

public delegate void MySqlInfoMessageEventHandler(
objectsender,
MySqlInfoMessageEventArgsargs
);

Requirements

Namespace: MySql.Data.MySqlClient

Assembly: MySql.Data (in MySql.Data.dll)

See Also

MySql.Data.MySqlClient Namespace

MySqlInfoMessageEventArgs Class

Provides data for the InfoMessage event. This class cannot be inherited.

For a list of all members of this type, see MySqlInfoMessageEventArgs Members .

Syntax: Visual Basic

Public Class MySqlInfoMessageEventArgs_
 Inherits EventArgs

Syntax: C#

public class MySqlInfoMessageEventArgs : EventArgs

Thread Safety

Public static (Shared in Visual Basic) members of this type are safe for multithreaded operations. Instance members are not guaranteed to be thread-safe.

Requirements

Namespace: MySql.Data.MySqlClient

Assembly: MySql.Data (in MySql.Data.dll)

See Also

MySqlInfoMessageEventArgs Members, MySql.Data.MySqlClient Namespace

MySqlInfoMessageEventArgs Members

MySqlInfoMessageEventArgs overview

Public Instance Constructors

MySqlInfoMessageEventArgs Constructor Initializes a new instance of the MySqlInfoMessageEventArgs class.

Public Instance Fields

errors

Public Instance Methods

Equals (inherited from Object) Determines whether the specified Object is equal to the current Object.
GetHashCode (inherited from Object) Serves as a hash function for a particular type. GetHashCode is suitable for use in hashing algorithms and data structures like a hash table.
GetType (inherited from Object) Gets the Type of the current instance.
ToString (inherited from Object) Returns a String that represents the current Object.

Protected Instance Methods

Finalize (inherited from Object) Allows an Object to attempt to free resources and perform other cleanup operations before the Object is reclaimed by garbage collection.
MemberwiseClone (inherited from Object) Creates a shallow copy of the current Object.

See Also

MySqlInfoMessageEventArgs Class, MySql.Data.MySqlClient Namespace

MySqlInfoMessageEventArgs Constructor

Initializes a new instance of the MySqlInfoMessageEventArgs class.

Syntax: Visual Basic

Public Sub New()

Syntax: C#

public MySqlInfoMessageEventArgs();

See Also

MySqlInfoMessageEventArgs Class, MySql.Data.MySqlClient Namespace

MySqlInfoMessageEventArgs.errors Field

Syntax: Visual Basic

Public errors As MySqlError()

Syntax: C#

public MySqlError[] errors;

See Also

MySqlInfoMessageEventArgs Class, MySql.Data.MySqlClient Namespace

MySqlError Class

Collection of error codes that can be returned by the server

For a list of all members of this type, see MySqlError Members .

Syntax: Visual Basic

Public Class MySqlError

Syntax: C#

public class MySqlError

Thread Safety

Public static (Shared in Visual Basic) members of this type are safe for multithreaded operations. Instance members are not guaranteed to be thread-safe.

Requirements

Namespace: MySql.Data.MySqlClient

Assembly: MySql.Data (in MySql.Data.dll)

See Also

MySqlError Members, MySql.Data.MySqlClient Namespace

MySqlError Members

MySqlError overview

Public Instance Constructors

MySqlError Constructor

Public Instance Properties

Code Error code
Level Error level
Message Error message

Public Instance Methods

Equals (inherited from Object) Determines whether the specified Object is equal to the current Object.
GetHashCode (inherited from Object) Serves as a hash function for a particular type. GetHashCode is suitable for use in hashing algorithms and data structures like a hash table.
GetType (inherited from Object) Gets the Type of the current instance.
ToString (inherited from Object) Returns a String that represents the current Object.

Protected Instance Methods

Finalize (inherited from Object) Allows an Object to attempt to free resources and perform other cleanup operations before the Object is reclaimed by garbage collection.
MemberwiseClone (inherited from Object) Creates a shallow copy of the current Object.

See Also

MySqlError Class, MySql.Data.MySqlClient Namespace

MySqlError Constructor

Syntax: Visual Basic

Public Sub New( _
 ByVal level As String, _
 ByVal code As Integer, _
 ByVal message As String _
)

Syntax: C#

public MySqlError(
stringlevel,
intcode,
stringmessage
);

Parameters

See Also

MySqlError Class, MySql.Data.MySqlClient Namespace

Code Property

Error code

Syntax: Visual Basic

Public ReadOnly Property Code As Integer

Syntax: C#

public int Code {get;}

See Also

MySqlError Class, MySql.Data.MySqlClient Namespace

Level Property

Error level

Syntax: Visual Basic

Public ReadOnly Property Level As String

Syntax: C#

public string Level {get;}

See Also

MySqlError Class, MySql.Data.MySqlClient Namespace

Message Property

Error message

Syntax: Visual Basic

Public ReadOnly Property Message As String

Syntax: C#

public string Message {get;}

See Also

MySqlError Class, MySql.Data.MySqlClient Namespace

MySqlConnection.StateChange Event

Syntax: Visual Basic

Public Event StateChange As StateChangeEventHandler

Syntax: C#

public event StateChangeEventHandler StateChange;

See Also

MySqlConnection Class, MySql.Data.MySqlClient Namespace

MySqlCommand Constructor

Syntax: Visual Basic

Overloads Public Sub New( _
 ByVal cmdText As String, _
 ByVal connection As MySqlConnection, _
 ByVal transaction As MySqlTransaction _
)

Syntax: C#

public MySqlCommand(
stringcmdText,
MySqlConnectionconnection,
MySqlTransactiontransaction
);

See Also

MySqlCommand Class, MySql.Data.MySqlClient Namespace, MySqlCommand Constructor Overload List

CommandText Property

Syntax: Visual Basic

NotOverridable Public Property CommandText As String _
_
 Implements IDbCommand.CommandText

Syntax: C#

public string CommandText {get; set;}

Implements

IDbCommand.CommandText

See Also

MySqlCommand Class, MySql.Data.MySqlClient Namespace

CommandTimeout Property

Syntax: Visual Basic

NotOverridable Public Property CommandTimeout As Integer _
_
 Implements IDbCommand.CommandTimeout

Syntax: C#

public int CommandTimeout {get; set;}

Implements

IDbCommand.CommandTimeout

See Also

MySqlCommand Class, MySql.Data.MySqlClient Namespace

CommandType Property

Syntax: Visual Basic

NotOverridable Public Property CommandType As CommandType _
_
 Implements IDbCommand.CommandType

Syntax: C#

public System.Data.CommandType CommandType {get; set;}

Implements

IDbCommand.CommandType

See Also

MySqlCommand Class, MySql.Data.MySqlClient Namespace

Connection Property

Syntax: Visual Basic

Public Property Connection As MySqlConnection

Syntax: C#

public MySqlConnection Connection {get; set;}

See Also

MySqlCommand Class, MySql.Data.MySqlClient Namespace

IsPrepared Property

Syntax: Visual Basic

Public ReadOnly Property IsPrepared As Boolean

Syntax: C#

public bool IsPrepared {get;}

See Also

MySqlCommand Class, MySql.Data.MySqlClient Namespace

Parameters Property
MySqlParameterCollection Class

Syntax: Visual Basic

Public ReadOnly Property Parameters As MySqlParameterCollection

Syntax: C#

public MySqlParameterCollection Parameters {get;}

See Also

MySqlCommand Class, MySql.Data.MySqlClient Namespace

MySqlParameterCollection Class
MySqlParameterCollection Members

Represents a collection of parameters relevant to a MySqlCommand as well as their respective mappings to columns in a DataSet. This class cannot be inherited.

For a list of all members of this type, see MySqlParameterCollection Members .

Syntax: Visual Basic

NotInheritable Public Class MySqlParameterCollection_
 Inherits MarshalByRefObject_
 Implements IDataParameterCollection, IList, ICollection, IEnumerable

Syntax: C#

public sealed class MySqlParameterCollection : MarshalByRefObject, IDataParameterCollection, IList, ICollection, IEnumerable

Thread Safety

Public static (Shared in Visual Basic) members of this type are safe for multithreaded operations. Instance members are not guaranteed to be thread-safe.

Requirements

Namespace: MySql.Data.MySqlClient

Assembly: MySql.Data (in MySql.Data.dll)

See Also

MySqlParameterCollection Members, MySql.Data.MySqlClient Namespace

MySqlParameterCollection Members
MySqlParameterCollection Constructor
Count Property
Item Property
Add Method
MySqlParameterCollection.Clear Method
Contains Method
MySqlParameterCollection.CopyTo Method
IndexOf Method
MySqlParameterCollection.Insert Method
MySqlParameterCollection.Remove Method
RemoveAt Method

MySqlParameterCollection overview

Public Instance Constructors

MySqlParameterCollection Constructor Initializes a new instance of the MySqlParameterCollection class.

Public Instance Properties

Count Gets the number of MySqlParameter objects in the collection.
Item Overloaded. Gets the MySqlParameter with a specified attribute. In C#, this property is the indexer for the MySqlParameterCollection class.

Public Instance Methods

Add Overloaded. Adds the specified MySqlParameter object to the MySqlParameterCollection.
Clear Removes all items from the collection.
Contains Overloaded. Gets a value indicating whether a MySqlParameter exists in the collection.
CopyTo Copies MySqlParameter objects from the MySqlParameterCollection to the specified array.
CreateObjRef (inherited from MarshalByRefObject) Creates an object that contains all the relevant information required to generate a proxy used to communicate with a remote object.
Equals (inherited from Object) Determines whether the specified Object is equal to the current Object.
GetHashCode (inherited from Object) Serves as a hash function for a particular type. GetHashCode is suitable for use in hashing algorithms and data structures like a hash table.
GetLifetimeService (inherited from MarshalByRefObject) Retrieves the current lifetime service object that controls the lifetime policy for this instance.
GetType (inherited from Object) Gets the Type of the current instance.
IndexOf Overloaded. Gets the location of a MySqlParameter in the collection.
InitializeLifetimeService (inherited from MarshalByRefObject) Obtains a lifetime service object to control the lifetime policy for this instance.
Insert Inserts a MySqlParameter into the collection at the specified index.
Remove Removes the specified MySqlParameter from the collection.
RemoveAt Overloaded. Removes the specified MySqlParameter from the collection.
ToString (inherited from Object) Returns a String that represents the current Object.

See Also

MySqlParameterCollection Class, MySql.Data.MySqlClient Namespace

MySqlParameterCollection Constructor

Initializes a new instance of the MySqlParameterCollection class.

Syntax: Visual Basic

Public Sub New()

Syntax: C#

public MySqlParameterCollection();

See Also

MySqlParameterCollection Class, MySql.Data.MySqlClient Namespace

Count Property

Gets the number of MySqlParameter objects in the collection.

Syntax: Visual Basic

NotOverridable Public ReadOnly Property Count As Integer _
_
 Implements ICollection.Count

Syntax: C#

public int Count {get;}

Implements

ICollection.Count

See Also

MySqlParameterCollection Class, MySql.Data.MySqlClient Namespace

Item Property

Gets the MySqlParameter with a specified attribute. In C#, this property is the indexer for the MySqlParameterCollection class.

Overload List

Gets the MySqlParameter at the specified index.

Gets the MySqlParameter with the specified name.

See Also

MySqlParameterCollection Class, MySql.Data.MySqlClient Namespace

MySqlParameter Class

Represents a parameter to a MySqlCommand, and optionally, its mapping to DataSetcolumns. This class cannot be inherited.

For a list of all members of this type, see MySqlParameter Members .

Syntax: Visual Basic

NotInheritable Public Class MySqlParameter_
 Inherits MarshalByRefObject_
 Implements IDataParameter, IDbDataParameter, ICloneable

Syntax: C#

public sealed class MySqlParameter : MarshalByRefObject, IDataParameter, IDbDataParameter, ICloneable

Thread Safety

Public static (Shared in Visual Basic) members of this type are safe for multithreaded operations. Instance members are not guaranteed to be thread-safe.

Requirements

Namespace: MySql.Data.MySqlClient

Assembly: MySql.Data (in MySql.Data.dll)

See Also

MySqlParameter Members, MySql.Data.MySqlClient Namespace

MySqlParameter Members

MySqlParameter overview

Public Instance Constructors

MySqlParameter Overloaded. Initializes a new instance of the MySqlParameter class.

Public Instance Properties

DbType Gets or sets the DbType of the parameter.
Direction Gets or sets a value indicating whether the parameter is input-only, output-only, bidirectional, or a stored procedure return value parameter. As of MariaDB version 4.1 and earlier, input-only is the only valid choice.
IsNullable Gets or sets a value indicating whether the parameter accepts null values.
IsUnsigned
MySqlDbType Gets or sets the MySqlDbType of the parameter.
ParameterName Gets or sets the name of the MySqlParameter.
Precision Gets or sets the maximum number of digits used to represent the Value property.
Scale Gets or sets the number of decimal places to which Value is resolved.
Size Gets or sets the maximum size, in bytes, of the data within the column.
SourceColumn Gets or sets the name of the source column that is mapped to the DataSetand used for loading or returning the Value.
SourceVersion Gets or sets the DataRowVersion to use when loading Value.
Value Gets or sets the value of the parameter.

Public Instance Methods

CreateObjRef (inherited from MarshalByRefObject) Creates an object that contains all the relevant information required to generate a proxy used to communicate with a remote object.
Equals (inherited from Object) Determines whether the specified Object is equal to the current Object.
GetHashCode (inherited from Object) Serves as a hash function for a particular type. GetHashCode is suitable for use in hashing algorithms and data structures like a hash table.
GetLifetimeService (inherited from MarshalByRefObject) Retrieves the current lifetime service object that controls the lifetime policy for this instance.
GetType (inherited from Object) Gets the Type of the current instance.
InitializeLifetimeService (inherited from MarshalByRefObject) Obtains a lifetime service object to control the lifetime policy for this instance.
ToString Overridden. Gets a string containing the ParameterName.

See Also

MySqlParameter Class, MySql.Data.MySqlClient Namespace

MySqlParameter Constructor

Initializes a new instance of the MySqlParameter class.

Overload List

Initializes a new instance of the MySqlParameter class.

Initializes a new instance of the MySqlParameter class with the parameter name and the data type.

Initializes a new instance of the MySqlParameter class with the parameter name, the MySqlDbType, and the size.

Initializes a new instance of the MySqlParameter class with the parameter name, the type of the parameter, the size of the parameter, a ParameterDirection, the precision of the parameter, the scale of the parameter, the source column, a DataRowVersion to use, and the value of the parameter.

Initializes a new instance of the MySqlParameter class with the parameter name, the MySqlDbType, the size, and the source column name.

Initializes a new instance of the MySqlParameter class with the parameter name and a value of the new MySqlParameter.

See Also

MySqlParameter Class, MySql.Data.MySqlClient Namespace

MySqlParameter Constructor ()

Initializes a new instance of the MySqlParameter class.

Syntax: Visual Basic

Overloads Public Sub New()

Syntax: C#

public MySqlParameter();

See Also

MySqlParameter Class, MySql.Data.MySqlClient Namespace, MySqlParameter Constructor Overload List

MySqlParameter Constructor

Initializes a new instance of the MySqlParameter class with the parameter name and the data type.

Syntax: Visual Basic

Overloads Public Sub New( _
 ByVal parameterName As String, _
 ByVal dbType As MySqlDbType _
)

Syntax: C#

public MySqlParameter(
stringparameterName,
MySqlDbTypedbType
);

Parameters

See Also

MySqlParameter Class, MySql.Data.MySqlClient Namespace, MySqlParameter Constructor Overload List

MySqlDbType Enumeration

Specifies MySQL-specific data type of a field, property, for use in a MySqlParameter.

Syntax: Visual Basic

Public Enum MySqlDbType

Syntax: C#

public enum MySqlDbType

Members

Member Name Description
Newdate Obsolete. Use Datetime or Date type.
Timestamp A timestamp. The range is '1970-01-01 00:00:01.000000' to '2038-01-19 03:14:07.999999'. (Fractional seconds can only be stored with a MariaDB 5.6.4 or higher database server.)
Time The range is '-838:59:59.000000' to '838:59:59.000000'. (Fractional seconds can only be stored with a MariaDB 5.6.4 or higher database server.)
Date The supported range is '1000-01-01' to '9999-12-31'.
Datetime The supported range is '1000-01-01 00:00:00.000000' to '9999-12-31 23:59:59.999999'. (Fractional seconds can only be stored with a MariaDB 5.6.4 or higher database server.)
Year A year in 2- or 4-digit format (default is 4-digit). The allowable values are 1901 to 2155, 0000 in the 4-digit year format, and 1970-2069 if you use the 2-digit format (70-69).
TinyBlob A BLOB column with a maximum length of 255 (2^8 - 1) characters.
Blob A BLOB column with a maximum length of 65535 (2^16 - 1) characters.
MediumBlob A BLOB column with a maximum length of 16777215 (2^24 - 1) characters.
LongBlob A BLOB column with a maximum length of 4294967295 or 4G (2^32 - 1) characters.
Int16 A 16-bit signed integer. The signed range is -32768 to 32767. The unsigned range is 0 to 65535.
Int24 Specifies a 24 (3 byte) signed or unsigned value.
Int32 A 32-bit signed integer.
Int64 A 64-bit signed integer.
Byte The signed range is -128 to 127. The unsigned range is 0 to 255.
Float A small (single-precision) floating-point number. Allowable values are -3.402823466E+38 to -1.175494351E-38, 0, and 1.175494351E-38 to 3.402823466E+38.
Double A normal-size (double-precision) floating-point number. Allowable values are -1.7976931348623157E+308 to -2.2250738585072014E-308, 0, and 2.2250738585072014E-308 to 1.7976931348623157E+308.
UByte An 8-bit unsigned value.
UInt16 A 16-bit unsigned value.
UInt24 A 24-bit unsigned value.
UInt32 A 32-bit unsigned value.
UInt64 A 64-bit unsigned value.
Decimal A fixed precision and scale numeric value between -10^38-1 and 10^38-1.
NewDecimal New Decimal
Set A set. A string object that can have zero or more values, each of which must be chosen from the list of values 'value1', 'value2', ... A SET can have a maximum of 64 members.
String Obsolete. Use VarChar type.
VarChar A variable-length string containing 0 to 255 characters.
VarString A variable-length string containing 0 to 65535 characters.
Enum An enumeration. A string object that can have only one value, chosen from the list of values 'value1', 'value2', ..., NULL or the special '' error value. An ENUM can have a maximum of 65535 distinct values.
Geometry
Bit Bit-field data type.
TinyText A nonbinary string column supporting a maximum length of 255 (2^8 - 1) characters.
Text A nonbinary string column supporting a maximum length of 65535 (2^16 - 1) characters.
MediumText A nonbinary string column supporting a maximum length of 16777215 (2^24 - 1) characters.
LongText A nonbinary string column supporting a maximum length of 4294967295 (2^32 - 1) characters.

Requirements

Namespace: MySql.Data.MySqlClient

Assembly: MySql.Data (in MySql.Data.dll)

See Also

MySql.Data.MySqlClient Namespace

MySqlParameter Constructor (String, MySqlDbType, Int32)

Initializes a new instance of the MySqlParameter class with the parameter name, the MySqlDbType, and the size.

Syntax: Visual Basic

Overloads Public Sub New( _
 ByVal parameterName As String, _
 ByVal dbType As MySqlDbType, _
 ByVal size As Integer _
)

Syntax: C#

public MySqlParameter(
stringparameterName,
MySqlDbTypedbType,
intsize
);

Parameters

See Also

MySqlParameter Class, MySql.Data.MySqlClient Namespace, MySqlParameter Constructor Overload List

MySqlParameter Constructor

Initializes a new instance of the MySqlParameter class with the parameter name, the type of the parameter, the size of the parameter, a ParameterDirection, the precision of the parameter, the scale of the parameter, the source column, a DataRowVersion to use, and the value of the parameter.

Syntax: Visual Basic

Overloads Public Sub New( _
 ByVal parameterName As String, _
 ByVal dbType As MySqlDbType, _
 ByVal size As Integer, _
 ByVal direction As ParameterDirection, _
 ByVal isNullable As Boolean, _
 ByVal precision As Byte, _
 ByVal scale As Byte, _
 ByVal sourceColumn As String, _
 ByVal sourceVersion As DataRowVersion, _
 ByVal value As Object _
)

Syntax: C#

public MySqlParameter(
stringparameterName,
MySqlDbTypedbType,
intsize,
ParameterDirectiondirection,
boolisNullable,
byteprecision,
bytescale,
stringsourceColumn,
DataRowVersionsourceVersion,
objectvalue
);

Parameters

Exceptions

Exception Type Condition
ArgumentException

See Also

MySqlParameter Class, MySql.Data.MySqlClient Namespace, MySqlParameter Constructor Overload List

Value Property

Gets or sets the value of the parameter.

Syntax: Visual Basic

NotOverridable Public Property Value As Object _
_
 Implements IDataParameter.Value

Syntax: C#

public object Value {get; set;}

Implements

IDataParameter.Value

See Also

MySqlParameter Class, MySql.Data.MySqlClient Namespace

MySqlParameter Constructor

Initializes a new instance of the MySqlParameter class with the parameter name, the MySqlDbType, the size, and the source column name.

Syntax: Visual Basic

Overloads Public Sub New( _
 ByVal parameterName As String, _
 ByVal dbType As MySqlDbType, _
 ByVal size As Integer, _
 ByVal sourceColumn As String _
)

Syntax: C#

public MySqlParameter(
stringparameterName,
MySqlDbTypedbType,
intsize,
stringsourceColumn
);

Parameters

See Also

MySqlParameter Class, MySql.Data.MySqlClient Namespace, MySqlParameter Constructor Overload List

MySqlParameter Constructor

Initializes a new instance of the MySqlParameter class with the parameter name and a value of the new MySqlParameter.

Syntax: Visual Basic

Overloads Public Sub New( _
 ByVal parameterName As String, _
 ByVal value As Object _
)

Syntax: C#

public MySqlParameter(
stringparameterName,
objectvalue
);

Parameters

See Also

MySqlParameter Class, MySql.Data.MySqlClient Namespace, MySqlParameter Constructor Overload List

DbType Property

Gets or sets the DbType of the parameter.

Syntax: Visual Basic

NotOverridable Public Property DbType As DbType _
_
 Implements IDataParameter.DbType

Syntax: C#

public System.Data.DbType DbType {get; set;}

Implements

IDataParameter.DbType

See Also

MySqlParameter Class, MySql.Data.MySqlClient Namespace

Direction Property

Gets or sets a value indicating whether the parameter is input-only, output-only, bidirectional, or a stored procedure return value parameter. As of MariaDB version 4.1 and earlier, input-only is the only valid choice.

Syntax: Visual Basic

NotOverridable Public Property Direction As ParameterDirection _
_
 Implements IDataParameter.Direction

Syntax: C#

public System.Data.ParameterDirection Direction {get; set;}

Implements

IDataParameter.Direction

See Also

MySqlParameter Class, MySql.Data.MySqlClient Namespace

IsNullable Property

Gets or sets a value indicating whether the parameter accepts null values.

Syntax: Visual Basic

NotOverridable Public Property IsNullable As Boolean _
_
 Implements IDataParameter.IsNullable

Syntax: C#

public bool IsNullable {get; set;}

Implements

IDataParameter.IsNullable

See Also

MySqlParameter Class, MySql.Data.MySqlClient Namespace

IsUnsigned Property

Syntax: Visual Basic

Public Property IsUnsigned As Boolean

Syntax: C#

public bool IsUnsigned {get; set;}

See Also

MySqlParameter Class, MySql.Data.MySqlClient Namespace

MySqlDbType Property

Gets or sets the MySqlDbType of the parameter.

Syntax: Visual Basic

Public Property MySqlDbType As MySqlDbType

Syntax: C#

public MySqlDbType MySqlDbType {get; set;}

See Also

MySqlParameter Class, MySql.Data.MySqlClient Namespace

ParameterName Property

Gets or sets the name of the MySqlParameter.

Syntax: Visual Basic

NotOverridable Public Property ParameterName As String _
_
 Implements IDataParameter.ParameterName

Syntax: C#

public string ParameterName {get; set;}

Implements

IDataParameter.ParameterName

See Also

MySqlParameter Class, MySql.Data.MySqlClient Namespace

Precision Property

Gets or sets the maximum number of digits used to represent the Value property.

Syntax: Visual Basic

NotOverridable Public Property Precision As Byte _
_
 Implements IDbDataParameter.Precision

Syntax: C#

public byte Precision {get; set;}

Implements

IDbDataParameter.Precision

See Also

MySqlParameter Class, MySql.Data.MySqlClient Namespace

Scale Property

Gets or sets the number of decimal places to which Value is resolved.

Syntax: Visual Basic

NotOverridable Public Property Scale As Byte _
_
 Implements IDbDataParameter.Scale

Syntax: C#

public byte Scale {get; set;}

Implements

IDbDataParameter.Scale

See Also

MySqlParameter Class, MySql.Data.MySqlClient Namespace

Size Property

Gets or sets the maximum size, in bytes, of the data within the column.

Syntax: Visual Basic

NotOverridable Public Property Size As Integer _
_
 Implements IDbDataParameter.Size

Syntax: C#

public int Size {get; set;}

Implements

IDbDataParameter.Size

See Also

MySqlParameter Class, MySql.Data.MySqlClient Namespace

SourceColumn Property

Gets or sets the name of the source column that is mapped to the DataSetand used for loading or returning the Value.

Syntax: Visual Basic

NotOverridable Public Property SourceColumn As String _
_
 Implements IDataParameter.SourceColumn

Syntax: C#

public string SourceColumn {get; set;}

Implements

IDataParameter.SourceColumn

See Also

MySqlParameter Class, MySql.Data.MySqlClient Namespace

SourceVersion Property

Gets or sets the DataRowVersion to use when loading Value.

Syntax: Visual Basic

NotOverridable Public Property SourceVersion As DataRowVersion _
_
 Implements IDataParameter.SourceVersion

Syntax: C#

public System.Data.DataRowVersion SourceVersion {get; set;}

Implements

IDataParameter.SourceVersion

See Also

MySqlParameter Class, MySql.Data.MySqlClient Namespace

MySqlParameter.ToString Method

Overridden. Gets a string containing the ParameterName.

Syntax: Visual Basic

Overrides Public Function ToString() As String

Syntax: C#

public override string ToString();

Return Value

See Also

MySqlParameter Class, MySql.Data.MySqlClient Namespace

Item Property (Int32)

Gets the MySqlParameter at the specified index.

Syntax: Visual Basic

Overloads Public Default Property Item( _
 ByVal index As Integer _
) As MySqlParameter

Syntax: C#

public MySqlParameter this[
intindex
] {get; set;}

See Also

MySqlParameterCollection Class, MySql.Data.MySqlClient Namespace, MySqlParameterCollection.Item Overload List

Item Property (String)

Gets the MySqlParameter with the specified name.

Syntax: Visual Basic

Overloads Public Default Property Item( _
 ByVal name As String _
) As MySqlParameter

Syntax: C#

public MySqlParameter this[
stringname
] {get; set;}

See Also

MySqlParameterCollection Class, MySql.Data.MySqlClient Namespace, MySqlParameterCollection.Item Overload List

Add Method

Adds the specified MySqlParameter object to the MySqlParameterCollection.

Overload List

Adds the specified MySqlParameter object to the MySqlParameterCollection.

Adds the specified MySqlParameter object to the MySqlParameterCollection.

Adds a MySqlParameter to the MySqlParameterCollection given the parameter name and the data type.

Adds a MySqlParameter to the MySqlParameterCollection with the parameter name, the data type, and the column length.

Adds a MySqlParameter to the MySqlParameterCollection with the parameter name, the data type, the column length, and the source column name.

Adds a MySqlParameter to the MySqlParameterCollection given the specified parameter name and value.

See Also

MySqlParameterCollection Class, MySql.Data.MySqlClient Namespace

MySqlParameterCollection.Add Method

Adds the specified MySqlParameter object to the MySqlParameterCollection.

Syntax: Visual Basic

Overloads Public Function Add( _
 ByVal value As MySqlParameter _
) As MySqlParameter

Syntax: C#

public MySqlParameter Add(
MySqlParametervalue
);

Parameters

Return Value

The newly added MySqlParameter object.

See Also

MySqlParameterCollection Class, MySql.Data.MySqlClient Namespace, MySqlParameterCollection.Add Overload List

MySqlParameterCollection.Add Method

Adds the specified MySqlParameter object to the MySqlParameterCollection.

Syntax: Visual Basic

NotOverridable Overloads Public Function Add( _
 ByVal value As Object _
) As Integer _
_
 Implements IList.Add

Syntax: C#

public int Add(
objectvalue
);

Parameters

Return Value

The index of the new MySqlParameter object.

Implements

IList.Add

See Also

MySqlParameterCollection Class, MySql.Data.MySqlClient Namespace, MySqlParameterCollection.Add Overload List

MySqlParameterCollection.Add Method

Adds a MySqlParameter to the MySqlParameterCollection given the parameter name and the data type.

Syntax: Visual Basic

Overloads Public Function Add( _
 ByVal parameterName As String, _
 ByVal dbType As MySqlDbType _
) As MySqlParameter

Syntax: C#

public MySqlParameter Add(
stringparameterName,
MySqlDbTypedbType
);

Parameters

Return Value

The newly added MySqlParameter object.

See Also

MySqlParameterCollection Class, MySql.Data.MySqlClient Namespace, MySqlParameterCollection.Add Overload List

MySqlParameterCollection.Add Method

Adds a MySqlParameter to the MySqlParameterCollection with the parameter name, the data type, and the column length.

Syntax: Visual Basic

Overloads Public Function Add( _
 ByVal parameterName As String, _
 ByVal dbType As MySqlDbType, _
 ByVal size As Integer _
) As MySqlParameter

Syntax: C#

public MySqlParameter Add(
stringparameterName,
MySqlDbTypedbType,
intsize
);

Parameters

Return Value

The newly added MySqlParameter object.

See Also

MySqlParameterCollection Class, MySql.Data.MySqlClient Namespace, MySqlParameterCollection.Add Overload List

MySqlParameterCollection.Add Method

Adds a MySqlParameter to the MySqlParameterCollection with the parameter name, the data type, the column length, and the source column name.

Syntax: Visual Basic

Overloads Public Function Add( _
 ByVal parameterName As String, _
 ByVal dbType As MySqlDbType, _
 ByVal size As Integer, _
 ByVal sourceColumn As String _
) As MySqlParameter

Syntax: C#

public MySqlParameter Add(
stringparameterName,
MySqlDbTypedbType,
intsize,
stringsourceColumn
);

Parameters

Return Value

The newly added MySqlParameter object.

See Also

MySqlParameterCollection Class, MySql.Data.MySqlClient Namespace, MySqlParameterCollection.Add Overload List

MySqlParameterCollection.Add Method

Adds a MySqlParameter to the MySqlParameterCollection given the specified parameter name and value.

Syntax: Visual Basic

Overloads Public Function Add( _
 ByVal parameterName As String, _
 ByVal value As Object _
) As MySqlParameter

Syntax: C#

public MySqlParameter Add(
stringparameterName,
objectvalue
);

Parameters

Return Value

The newly added MySqlParameter object.

See Also

MySqlParameterCollection Class, MySql.Data.MySqlClient Namespace, MySqlParameterCollection.Add Overload List

MySqlParameterCollection.Clear Method

Removes all items from the collection.

Syntax: Visual Basic

NotOverridable Public Sub Clear() _
_
 Implements IList.Clear

Syntax: C#

public void Clear();

Implements

IList.Clear

See Also

MySqlParameterCollection Class, MySql.Data.MySqlClient Namespace

Contains Method

Gets a value indicating whether a MySqlParameter exists in the collection.

Overload List

Gets a value indicating whether a MySqlParameter exists in the collection.

Gets a value indicating whether a MySqlParameter with the specified parameter name exists in the collection.

See Also

MySqlParameterCollection Class, MySql.Data.MySqlClient Namespace

MySqlParameterCollection.Contains Method

Gets a value indicating whether a MySqlParameter exists in the collection.

Syntax: Visual Basic

NotOverridable Overloads Public Function Contains( _
 ByVal value As Object _
) As Boolean _
_
 Implements IList.Contains

Syntax: C#

public bool Contains(
objectvalue
);

Parameters

Return Value

true if the collection contains the MySqlParameter object; otherwise, false.

Implements

IList.Contains

See Also

MySqlParameterCollection Class, MySql.Data.MySqlClient Namespace, MySqlParameterCollection.Contains Overload List

MySqlParameterCollection.Contains Method

Gets a value indicating whether a MySqlParameter with the specified parameter name exists in the collection.

Syntax: Visual Basic

NotOverridable Overloads Public Function Contains( _
 ByVal name As String _
) As Boolean _
_
 Implements IDataParameterCollection.Contains

Syntax: C#

public bool Contains(
stringname
);

Parameters

Return Value

true if the collection contains the parameter; otherwise, false.

Implements

IDataParameterCollection.Contains

See Also

MySqlParameterCollection Class, MySql.Data.MySqlClient Namespace, MySqlParameterCollection.Contains Overload List

MySqlParameterCollection.CopyTo Method

Copies MySqlParameter objects from the MySqlParameterCollection to the specified array.

Syntax: Visual Basic

NotOverridable Public Sub CopyTo( _
 ByVal array As Array, _
 ByVal index As Integer _
) _
_
 Implements ICollection.CopyTo

Syntax: C#

public void CopyTo(
Arrayarray,
intindex
);

Parameters

Implements

ICollection.CopyTo

See Also

MySqlParameterCollection Class, MySql.Data.MySqlClient Namespace

IndexOf Method

Gets the location of a MySqlParameter in the collection.

Overload List

Gets the location of a MySqlParameter in the collection.

Gets the location of the MySqlParameter in the collection with a specific parameter name.

See Also

MySqlParameterCollection Class, MySql.Data.MySqlClient Namespace

MySqlParameterCollection.IndexOf Method

Gets the location of a MySqlParameter in the collection.

Syntax: Visual Basic

NotOverridable Overloads Public Function IndexOf( _
 ByVal value As Object _
) As Integer _
_
 Implements IList.IndexOf

Syntax: C#

public int IndexOf(
objectvalue
);

Parameters

Return Value

The zero-based location of the MySqlParameter in the collection.

Implements

IList.IndexOf

See Also

MySqlParameterCollection Class, MySql.Data.MySqlClient Namespace, MySqlParameterCollection.IndexOf Overload List

MySqlParameterCollection.IndexOf Method

Gets the location of the MySqlParameter in the collection with a specific parameter name.

Syntax: Visual Basic

NotOverridable Overloads Public Function IndexOf( _
 ByVal parameterName As String _
) As Integer _
_
 Implements IDataParameterCollection.IndexOf

Syntax: C#

public int IndexOf(
stringparameterName
);

Parameters

Return Value

The zero-based location of the MySqlParameter in the collection.

Implements

IDataParameterCollection.IndexOf

See Also

MySqlParameterCollection Class, MySql.Data.MySqlClient Namespace, MySqlParameterCollection.IndexOf Overload List

MySqlParameterCollection.Insert Method

Inserts a MySqlParameter into the collection at the specified index.

Syntax: Visual Basic

NotOverridable Public Sub Insert( _
 ByVal index As Integer, _
 ByVal value As Object _
) _
_
 Implements IList.Insert

Syntax: C#

public void Insert(
intindex,
objectvalue
);

Parameters

Implements

IList.Insert

See Also

MySqlParameterCollection Class, MySql.Data.MySqlClient Namespace

MySqlParameterCollection.Remove Method

Removes the specified MySqlParameter from the collection.

Syntax: Visual Basic

NotOverridable Public Sub Remove( _
 ByVal value As Object _
) _
_
 Implements IList.Remove

Syntax: C#

public void Remove(
objectvalue
);

Parameters

Implements

IList.Remove

See Also

MySqlParameterCollection Class, MySql.Data.MySqlClient Namespace

RemoveAt Method

Removes the specified MySqlParameter from the collection.

Overload List

Removes the specified MySqlParameter from the collection using a specific index.

Removes the specified MySqlParameter from the collection using the parameter name.

See Also

MySqlParameterCollection Class, MySql.Data.MySqlClient Namespace

MySqlParameterCollection.RemoveAt Method

Removes the specified MySqlParameter from the collection using a specific index.

Syntax: Visual Basic

NotOverridable Overloads Public Sub RemoveAt( _
 ByVal index As Integer _
) _
_
 Implements IList.RemoveAt

Syntax: C#

public void RemoveAt(
intindex
);

Parameters

Implements

IList.RemoveAt

See Also

MySqlParameterCollection Class, MySql.Data.MySqlClient Namespace, MySqlParameterCollection.RemoveAt Overload List

MySqlParameterCollection.RemoveAt Method

Removes the specified MySqlParameter from the collection using the parameter name.

Syntax: Visual Basic

NotOverridable Overloads Public Sub RemoveAt( _
 ByVal name As String _
) _
_
 Implements IDataParameterCollection.RemoveAt

Syntax: C#

public void RemoveAt(
stringname
);

Parameters

Implements

IDataParameterCollection.RemoveAt

See Also

MySqlParameterCollection Class, MySql.Data.MySqlClient Namespace, MySqlParameterCollection.RemoveAt Overload List

Transaction Property

Syntax: Visual Basic

Public Property Transaction As MySqlTransaction

Syntax: C#

public MySqlTransaction Transaction {get; set;}

See Also

MySqlCommand Class, MySql.Data.MySqlClient Namespace

UpdatedRowSource Property

Syntax: Visual Basic

NotOverridable Public Property UpdatedRowSource As UpdateRowSource _
_
 Implements IDbCommand.UpdatedRowSource

Syntax: C#

public System.Data.UpdateRowSource UpdatedRowSource {get; set;}

Implements

IDbCommand.UpdatedRowSource

See Also

MySqlCommand Class, MySql.Data.MySqlClient Namespace

MySqlCommand.Cancel Method

Attempts to cancel the execution of a MySqlCommand. This operation is not supported.

Syntax: Visual Basic

NotOverridable Public Sub Cancel() _
_
 Implements IDbCommand.Cancel

Syntax: C#

public void Cancel();

Implements

IDbCommand.Cancel

Remarks

Cancelling an executing command is currently not supported on any version of MySQL.

Exceptions

Exception Type Condition
NotSupportedException This operation is not supported.

See Also

MySqlCommand Class, MySql.Data.MySqlClient Namespace

MySqlCommand.CreateParameter Method

Creates a new instance of a MySqlParameter object.

Syntax: Visual Basic

Public Function CreateParameter() As MySqlParameter

Syntax: C#

public MySqlParameter CreateParameter();

Return Value

A MySqlParameter object.

Remarks

This method is a strongly-typed version of CreateParameter.

See Also

MySqlCommand Class, MySql.Data.MySqlClient Namespace

MySqlCommand.ExecuteNonQuery Method

Syntax: Visual Basic

NotOverridable Public Function ExecuteNonQuery() As Integer _
_
 Implements IDbCommand.ExecuteNonQuery

Syntax: C#

public int ExecuteNonQuery();

Implements

IDbCommand.ExecuteNonQuery

See Also

MySqlCommand Class, MySql.Data.MySqlClient Namespace

ExecuteReader Method
MySqlCommand.ExecuteReader Method
MySqlCommand.ExecuteReader Method

Overload List

See Also

MySqlCommand Class, MySql.Data.MySqlClient Namespace

MySqlCommand.ExecuteReader Method
MySqlDataReader Class

Syntax: Visual Basic

Overloads Public Function ExecuteReader() As MySqlDataReader

Syntax: C#

public MySqlDataReader ExecuteReader();

See Also

MySqlCommand Class, MySql.Data.MySqlClient Namespace, MySqlCommand.ExecuteReader Overload List

MySqlDataReader Class
MySqlDataReader Members

Provides a means of reading a forward-only stream of rows from a MariaDB database. This class cannot be inherited.

For a list of all members of this type, see MySqlDataReader Members .

Syntax: Visual Basic

NotInheritable Public Class MySqlDataReader_
 Inherits MarshalByRefObject_
 Implements IEnumerable, IDataReader, IDisposable, IDataRecord

Syntax: C#

public sealed class MySqlDataReader : MarshalByRefObject, IEnumerable, IDataReader, IDisposable, IDataRecord

Thread Safety

Public static (Shared in Visual Basic) members of this type are safe for multithreaded operations. Instance members are not guaranteed to be thread-safe.

Requirements

Namespace: MySql.Data.MySqlClient

Assembly: MySql.Data (in MySql.Data.dll)

See Also

MySqlDataReader Members, MySql.Data.MySqlClient Namespace

MySqlDataReader Members

MySqlDataReader overview

Public Instance Properties

Depth Gets a value indicating the depth of nesting for the current row. This method is not supported currently and always returns 0.
FieldCount Gets the number of columns in the current row.
HasRows Gets a value indicating whether the MySqlDataReader contains one or more rows.
IsClosed Gets a value indicating whether the data reader is closed.
Item Overloaded. Overloaded. Gets the value of a column in its native format. In C#, this property is the indexer for the MySqlDataReader class.
RecordsAffected Gets the number of rows changed, inserted, or deleted by execution of the SQL statement.

Public Instance Methods

Close Closes the MySqlDataReader object.
CreateObjRef (inherited from MarshalByRefObject) Creates an object that contains all the relevant information required to generate a proxy used to communicate with a remote object.
Equals (inherited from Object) Determines whether the specified Object is equal to the current Object.
GetBoolean Gets the value of the specified column as a Boolean.
GetByte Gets the value of the specified column as a byte.
GetBytes Reads a stream of bytes from the specified column offset into the buffer an array starting at the given buffer offset.
GetChar Gets the value of the specified column as a single character.
GetChars Reads a stream of characters from the specified column offset into the buffer as an array starting at the given buffer offset.
GetDataTypeName Gets the name of the source data type.
GetDateTime
GetDecimal
GetDouble
GetFieldType Gets the Type that is the data type of the object.
GetFloat
GetGuid
GetHashCode (inherited from Object) Serves as a hash function for a particular type. GetHashCode is suitable for use in hashing algorithms and data structures like a hash table.
GetInt16
GetInt32
GetInt64
GetLifetimeService (inherited from MarshalByRefObject) Retrieves the current lifetime service object that controls the lifetime policy for this instance.
GetMySqlDateTime
GetName Gets the name of the specified column.
GetOrdinal Gets the column ordinal, given the name of the column.
GetSchemaTable Returns a DataTable that describes the column metadata of the MySqlDataReader.
GetString
GetTimeSpan
GetType (inherited from Object) Gets the Type of the current instance.
GetUInt16
GetUInt32
GetUInt64
GetValue Gets the value of the specified column in its native format.
GetValues Gets all attribute columns in the collection for the current row.
InitializeLifetimeService (inherited from MarshalByRefObject) Obtains a lifetime service object to control the lifetime policy for this instance.
IsDBNull Gets a value indicating whether the column contains non-existent or missing values.
NextResult Advances the data reader to the next result, when reading the results of batch SQL statements.
Read Advances the MySqlDataReader to the next record.
ToString (inherited from Object) Returns a String that represents the current Object.

See Also

MySqlDataReader Class, MySql.Data.MySqlClient Namespace

Depth Property

Gets a value indicating the depth of nesting for the current row. This method is not supported currently and always returns 0.

Syntax: Visual Basic

NotOverridable Public ReadOnly Property Depth As Integer _
_
 Implements IDataReader.Depth

Syntax: C#

public int Depth {get;}

Implements

IDataReader.Depth

See Also

MySqlDataReader Class, MySql.Data.MySqlClient Namespace

FieldCount Property

Gets the number of columns in the current row.

Syntax: Visual Basic

NotOverridable Public ReadOnly Property FieldCount As Integer _
_
 Implements IDataRecord.FieldCount

Syntax: C#

public int FieldCount {get;}

Implements

IDataRecord.FieldCount

See Also

MySqlDataReader Class, MySql.Data.MySqlClient Namespace

HasRows Property

Gets a value indicating whether the MySqlDataReader contains one or more rows.

Syntax: Visual Basic

Public ReadOnly Property HasRows As Boolean

Syntax: C#

public bool HasRows {get;}

See Also

MySqlDataReader Class, MySql.Data.MySqlClient Namespace

IsClosed Property

Gets a value indicating whether the data reader is closed.

Syntax: Visual Basic

NotOverridable Public ReadOnly Property IsClosed As Boolean _
_
 Implements IDataReader.IsClosed

Syntax: C#

public bool IsClosed {get;}

Implements

IDataReader.IsClosed

See Also

MySqlDataReader Class, MySql.Data.MySqlClient Namespace

Item Property

Overloaded. Gets the value of a column in its native format. In C#, this property is the indexer for the MySqlDataReader class.

Overload List

Overloaded. Gets the value of a column in its native format. In C#, this property is the indexer for the MySqlDataReader class.

Gets the value of a column in its native format. In C#, this property is the indexer for the MySqlDataReader class.

See Also

MySqlDataReader Class, MySql.Data.MySqlClient Namespace

Item Property (Int32)

Overloaded. Gets the value of a column in its native format. In C#, this property is the indexer for the MySqlDataReader class.

Syntax: Visual Basic

NotOverridable Overloads Public Default ReadOnly Property Item( _
 ByVal i As Integer _
) _
_
 Implements IDataRecord.Item As Object _
_
 Implements IDataRecord.Item

Syntax: C#

public object this[
inti
] {get;}

Implements

IDataRecord.Item

See Also

MySqlDataReader Class, MySql.Data.MySqlClient Namespace, MySqlDataReader.Item Overload List

Item Property (String)

Gets the value of a column in its native format. In C#, this property is the indexer for the MySqlDataReader class.

Syntax: Visual Basic

NotOverridable Overloads Public Default ReadOnly Property Item( _
 ByVal name As String _
) _
_
 Implements IDataRecord.Item As Object _
_
 Implements IDataRecord.Item

Syntax: C#

public object this[
stringname
] {get;}

Implements

IDataRecord.Item

See Also

MySqlDataReader Class, MySql.Data.MySqlClient Namespace, MySqlDataReader.Item Overload List

RecordsAffected Property

Gets the number of rows changed, inserted, or deleted by execution of the SQL statement.

Syntax: Visual Basic

NotOverridable Public ReadOnly Property RecordsAffected As Integer _
_
 Implements IDataReader.RecordsAffected

Syntax: C#

public int RecordsAffected {get;}

Implements

IDataReader.RecordsAffected

See Also

MySqlDataReader Class, MySql.Data.MySqlClient Namespace

MySqlDataReader.Close Method

Closes the MySqlDataReader object.

Syntax: Visual Basic

NotOverridable Public Sub Close() _
_
 Implements IDataReader.Close

Syntax: C#

public void Close();

Implements

IDataReader.Close

See Also

MySqlDataReader Class, MySql.Data.MySqlClient Namespace

MySqlDataReader.GetBoolean Method

Gets the value of the specified column as a Boolean.

Syntax: Visual Basic

NotOverridable Public Function GetBoolean( _
 ByVal i As Integer _
) As Boolean _
_
 Implements IDataRecord.GetBoolean

Syntax: C#

public bool GetBoolean(
inti
);

Parameters

Return Value

Implements

IDataRecord.GetBoolean

See Also

MySqlDataReader Class, MySql.Data.MySqlClient Namespace

MySqlDataReader.GetByte Method

Gets the value of the specified column as a byte.

Syntax: Visual Basic

NotOverridable Public Function GetByte( _
 ByVal i As Integer _
) As Byte _
_
 Implements IDataRecord.GetByte

Syntax: C#

public byte GetByte(
inti
);

Parameters

Return Value

Implements

IDataRecord.GetByte

See Also

MySqlDataReader Class, MySql.Data.MySqlClient Namespace

MySqlDataReader.GetBytes Method

Reads a stream of bytes from the specified column offset into the buffer an array starting at the given buffer offset.

Syntax: Visual Basic

NotOverridable Public Function GetBytes( _
 ByVal i As Integer, _
 ByVal dataIndex As Long, _
 ByVal buffer As Byte(), _
 ByVal bufferIndex As Integer, _
 ByVal length As Integer _
) As Long _
_
 Implements IDataRecord.GetBytes

Syntax: C#

public long GetBytes(
inti,
longdataIndex,
byte[]buffer,
intbufferIndex,
intlength
);

Parameters

Return Value

The actual number of bytes read.

Implements

IDataRecord.GetBytes

See Also

MySqlDataReader Class, MySql.Data.MySqlClient Namespace

MySqlDataReader.GetChar Method

Gets the value of the specified column as a single character.

Syntax: Visual Basic

NotOverridable Public Function GetChar( _
 ByVal i As Integer _
) As Char _
_
 Implements IDataRecord.GetChar

Syntax: C#

public char GetChar(
inti
);

Parameters

Return Value

Implements

IDataRecord.GetChar

See Also

MySqlDataReader Class, MySql.Data.MySqlClient Namespace

MySqlDataReader.GetChars Method

Reads a stream of characters from the specified column offset into the buffer as an array starting at the given buffer offset.

Syntax: Visual Basic

NotOverridable Public Function GetChars( _
 ByVal i As Integer, _
 ByVal fieldOffset As Long, _
 ByVal buffer As Char(), _
 ByVal bufferoffset As Integer, _
 ByVal length As Integer _
) As Long _
_
 Implements IDataRecord.GetChars

Syntax: C#

public long GetChars(
inti,
longfieldOffset,
char[]buffer,
intbufferoffset,
intlength
);

Parameters

Return Value

Implements

IDataRecord.GetChars

See Also

MySqlDataReader Class, MySql.Data.MySqlClient Namespace

MySqlDataReader.GetDataTypeName Method

Gets the name of the source data type.

Syntax: Visual Basic

NotOverridable Public Function GetDataTypeName( _
 ByVal i As Integer _
) As String _
_
 Implements IDataRecord.GetDataTypeName

Syntax: C#

public string GetDataTypeName(
inti
);

Parameters

Return Value

Implements

IDataRecord.GetDataTypeName

See Also

MySqlDataReader Class, MySql.Data.MySqlClient Namespace

MySqlDataReader.GetDateTime Method

Syntax: Visual Basic

NotOverridable Public Function GetDateTime( _
 ByVal index As Integer _
) As Date _
_
 Implements IDataRecord.GetDateTime

Syntax: C#

public DateTime GetDateTime(
intindex
);

Implements

IDataRecord.GetDateTime

See Also

MySqlDataReader Class, MySql.Data.MySqlClient Namespace

MySqlDataReader.GetDecimal Method

Syntax: Visual Basic

NotOverridable Public Function GetDecimal( _
 ByVal index As Integer _
) As Decimal _
_
 Implements IDataRecord.GetDecimal

Syntax: C#

public decimal GetDecimal(
intindex
);

Implements

IDataRecord.GetDecimal

See Also

MySqlDataReader Class, MySql.Data.MySqlClient Namespace

MySqlDataReader.GetDouble Method

Syntax: Visual Basic

NotOverridable Public Function GetDouble( _
 ByVal index As Integer _
) As Double _
_
 Implements IDataRecord.GetDouble

Syntax: C#

public double GetDouble(
intindex
);

Implements

IDataRecord.GetDouble

See Also

MySqlDataReader Class, MySql.Data.MySqlClient Namespace

MySqlDataReader.GetFieldType Method

Gets the Type that is the data type of the object.

Syntax: Visual Basic

NotOverridable Public Function GetFieldType( _
 ByVal i As Integer _
) As Type _
_
 Implements IDataRecord.GetFieldType

Syntax: C#

public Type GetFieldType(
inti
);

Parameters

Return Value

Implements

IDataRecord.GetFieldType

See Also

MySqlDataReader Class, MySql.Data.MySqlClient Namespace

MySqlDataReader.GetFloat Method

Syntax: Visual Basic

NotOverridable Public Function GetFloat( _
 ByVal index As Integer _
) As Single _
_
 Implements IDataRecord.GetFloat

Syntax: C#

public float GetFloat(
intindex
);

Implements

IDataRecord.GetFloat

See Also

MySqlDataReader Class, MySql.Data.MySqlClient Namespace

MySqlDataReader.GetGuid Method

Syntax: Visual Basic

NotOverridable Public Function GetGuid( _
 ByVal index As Integer _
) As Guid _
_
 Implements IDataRecord.GetGuid

Syntax: C#

public Guid GetGuid(
intindex
);

Implements

IDataRecord.GetGuid

See Also

MySqlDataReader Class, MySql.Data.MySqlClient Namespace

MySqlDataReader.GetInt16 Method

Syntax: Visual Basic

NotOverridable Public Function GetInt16( _
 ByVal index As Integer _
) As Short _
_
 Implements IDataRecord.GetInt16

Syntax: C#

public short GetInt16(
intindex
);

Implements

IDataRecord.GetInt16

See Also

MySqlDataReader Class, MySql.Data.MySqlClient Namespace

MySqlDataReader.GetInt32 Method

Syntax: Visual Basic

NotOverridable Public Function GetInt32( _
 ByVal index As Integer _
) As Integer _
_
 Implements IDataRecord.GetInt32

Syntax: C#

public int GetInt32(
intindex
);

Implements

IDataRecord.GetInt32

See Also

MySqlDataReader Class, MySql.Data.MySqlClient Namespace

MySqlDataReader.GetInt64 Method

Syntax: Visual Basic

NotOverridable Public Function GetInt64( _
 ByVal index As Integer _
) As Long _
_
 Implements IDataRecord.GetInt64

Syntax: C#

public long GetInt64(
intindex
);

Implements

IDataRecord.GetInt64

See Also

MySqlDataReader Class, MySql.Data.MySqlClient Namespace

MySqlDataReader.GetMySqlDateTime Method

Syntax: Visual Basic

Public Function GetMySqlDateTime( _
 ByVal index As Integer _
) As MySqlDateTime

Syntax: C#

public MySqlDateTime GetMySqlDateTime(
intindex
);

See Also

MySqlDataReader Class, MySql.Data.MySqlClient Namespace

MySqlDataReader.GetName Method

Gets the name of the specified column.

Syntax: Visual Basic

NotOverridable Public Function GetName( _
 ByVal i As Integer _
) As String _
_
 Implements IDataRecord.GetName

Syntax: C#

public string GetName(
inti
);

Parameters

Return Value

Implements

IDataRecord.GetName

See Also

MySqlDataReader Class, MySql.Data.MySqlClient Namespace

MySqlDataReader.GetOrdinal Method

Gets the column ordinal, given the name of the column.

Syntax: Visual Basic

NotOverridable Public Function GetOrdinal( _
 ByVal name As String _
) As Integer _
_
 Implements IDataRecord.GetOrdinal

Syntax: C#

public int GetOrdinal(
stringname
);

Parameters

Return Value

Implements

IDataRecord.GetOrdinal

See Also

MySqlDataReader Class, MySql.Data.MySqlClient Namespace

MySqlDataReader.GetSchemaTable Method

Returns a DataTable that describes the column metadata of the MySqlDataReader.

Syntax: Visual Basic

NotOverridable Public Function GetSchemaTable() As DataTable _
_
 Implements IDataReader.GetSchemaTable

Syntax: C#

public DataTable GetSchemaTable();

Return Value

Implements

IDataReader.GetSchemaTable

See Also

MySqlDataReader Class, MySql.Data.MySqlClient Namespace

MySqlDataReader.GetString Method

Syntax: Visual Basic

NotOverridable Public Function GetString( _
 ByVal index As Integer _
) As String _
_
 Implements IDataRecord.GetString

Syntax: C#

public string GetString(
intindex
);

Implements

IDataRecord.GetString

See Also

MySqlDataReader Class, MySql.Data.MySqlClient Namespace

MySqlDataReader.GetTimeSpan Method

Syntax: Visual Basic

Public Function GetTimeSpan( _
 ByVal index As Integer _
) As TimeSpan

Syntax: C#

public TimeSpan GetTimeSpan(
intindex
);

See Also

MySqlDataReader Class, MySql.Data.MySqlClient Namespace

MySqlDataReader.GetUInt16 Method

Syntax: Visual Basic

Public Function GetUInt16( _
 ByVal index As Integer _
) As UInt16

Syntax: C#

public ushort GetUInt16(
intindex
);

See Also

MySqlDataReader Class, MySql.Data.MySqlClient Namespace

MySqlDataReader.GetUInt32 Method

Syntax: Visual Basic

Public Function GetUInt32( _
 ByVal index As Integer _
) As UInt32

Syntax: C#

public uint GetUInt32(
intindex
);

See Also

MySqlDataReader Class, MySql.Data.MySqlClient Namespace

MySqlDataReader.GetUInt64 Method

Syntax: Visual Basic

Public Function GetUInt64( _
 ByVal index As Integer _
) As UInt64

Syntax: C#

public ulong GetUInt64(
intindex
);

See Also

MySqlDataReader Class, MySql.Data.MySqlClient Namespace

MySqlDataReader.GetValue Method

Gets the value of the specified column in its native format.

Syntax: Visual Basic

NotOverridable Public Function GetValue( _
 ByVal i As Integer _
) As Object _
_
 Implements IDataRecord.GetValue

Syntax: C#

public object GetValue(
inti
);

Parameters

Return Value

Implements

IDataRecord.GetValue

See Also

MySqlDataReader Class, MySql.Data.MySqlClient Namespace

MySqlDataReader.GetValues Method

Gets all attribute columns in the collection for the current row.

Syntax: Visual Basic

NotOverridable Public Function GetValues( _
 ByVal values As Object() _
) As Integer _
_
 Implements IDataRecord.GetValues

Syntax: C#

public int GetValues(
object[]values
);

Parameters

Return Value

Implements

IDataRecord.GetValues

See Also

MySqlDataReader Class, MySql.Data.MySqlClient Namespace

MySqlDataReader.IsDBNull Method

Gets a value indicating whether the column contains non-existent or missing values.

Syntax: Visual Basic

NotOverridable Public Function IsDBNull( _
 ByVal i As Integer _
) As Boolean _
_
 Implements IDataRecord.IsDBNull

Syntax: C#

public bool IsDBNull(
inti
);

Parameters

Return Value

Implements

IDataRecord.IsDBNull

See Also

MySqlDataReader Class, MySql.Data.MySqlClient Namespace

MySqlDataReader.NextResult Method

Advances the data reader to the next result, when reading the results of batch SQL statements.

Syntax: Visual Basic

NotOverridable Public Function NextResult() As Boolean _
_
 Implements IDataReader.NextResult

Syntax: C#

public bool NextResult();

Return Value

Implements

IDataReader.NextResult

See Also

MySqlDataReader Class, MySql.Data.MySqlClient Namespace

MySqlDataReader.Read Method

Advances the MySqlDataReader to the next record.

Syntax: Visual Basic

NotOverridable Public Function Read() As Boolean _
_
 Implements IDataReader.Read

Syntax: C#

public bool Read();

Return Value

Implements

IDataReader.Read

See Also

MySqlDataReader Class, MySql.Data.MySqlClient Namespace

MySqlCommand.ExecuteReader Method

Syntax: Visual Basic

Overloads Public Function ExecuteReader( _
 ByVal behavior As CommandBehavior _
) As MySqlDataReader

Syntax: C#

public MySqlDataReader ExecuteReader(
CommandBehaviorbehavior
);

See Also

MySqlCommand Class, MySql.Data.MySqlClient Namespace, MySqlCommand.ExecuteReader Overload List

MySqlCommand.ExecuteScalar Method

Syntax: Visual Basic

NotOverridable Public Function ExecuteScalar() As Object _
_
 Implements IDbCommand.ExecuteScalar

Syntax: C#

public object ExecuteScalar();

Implements

IDbCommand.ExecuteScalar

See Also

MySqlCommand Class, MySql.Data.MySqlClient Namespace

MySqlCommand.Prepare Method

Syntax: Visual Basic

NotOverridable Public Sub Prepare() _
_
 Implements IDbCommand.Prepare

Syntax: C#

public void Prepare();

Implements

IDbCommand.Prepare

See Also

MySqlCommand Class, MySql.Data.MySqlClient Namespace

MySqlCommandBuilder Class
MySqlCommandBuilder Members

For a list of all members of this type, see MySqlCommandBuilder Members .

Syntax: Visual Basic

NotInheritable Public Class MySqlCommandBuilder_
 Inherits Component

Syntax: C#

public sealed class MySqlCommandBuilder : Component

Thread Safety

Public static (Shared in Visual Basic) members of this type are safe for multithreaded operations. Instance members are not guaranteed to be thread-safe.

Requirements

Namespace: MySql.Data.MySqlClient

Assembly: MySql.Data (in MySql.Data.dll)

See Also

MySqlCommandBuilder Members, MySql.Data.MySqlClient Namespace

MySqlCommandBuilder Members
DeriveParameters Method
MySqlCommandBuilder Constructor
DataAdapter Property
QuotePrefix Property
QuoteSuffix Property
MySqlCommandBuilder.GetDeleteCommand Method
MySqlCommandBuilder.GetInsertCommand Method
MySqlCommandBuilder.GetUpdateCommand Method
MySqlCommandBuilder.RefreshSchema Method

MySqlCommandBuilder overview

Public Static (Shared) Methods

DeriveParameters Overloaded. Retrieves parameter information from the stored procedure specified in the MySqlCommand and populates the Parameters collection of the specified MySqlCommand object. This method is not currently supported since stored procedures are not available in MySql.

Public Instance Constructors

MySqlCommandBuilder Overloaded. Initializes a new instance of the MySqlCommandBuilder class.

Public Instance Properties

Container (inherited from Component) Gets the IContainer that contains the Component.
DataAdapter
QuotePrefix
QuoteSuffix
Site (inherited from Component) Gets or sets the ISite of the Component.

Public Instance Methods

CreateObjRef (inherited from MarshalByRefObject) Creates an object that contains all the relevant information required to generate a proxy used to communicate with a remote object.
Dispose (inherited from Component) Releases all resources used by the Component.
Equals (inherited from Object) Determines whether the specified Object is equal to the current Object.
GetDeleteCommand
GetHashCode (inherited from Object) Serves as a hash function for a particular type. GetHashCode is suitable for use in hashing algorithms and data structures like a hash table.
GetInsertCommand
GetLifetimeService (inherited from MarshalByRefObject) Retrieves the current lifetime service object that controls the lifetime policy for this instance.
GetType (inherited from Object) Gets the Type of the current instance.
GetUpdateCommand
InitializeLifetimeService (inherited from MarshalByRefObject) Obtains a lifetime service object to control the lifetime policy for this instance.
RefreshSchema
ToString (inherited from Component) Returns a String containing the name of the Component, if any. This method should not be overridden.

Public Instance Events

Disposed (inherited from Component) Adds an event handler to listen to the Disposed event on the component.

See Also

MySqlCommandBuilder Class, MySql.Data.MySqlClient Namespace

DeriveParameters Method
MySqlCommandBuilder.DeriveParameters Method
MySqlCommandBuilder.DeriveParameters Method

Retrieves parameter information from the stored procedure specified in the MySqlCommand and populates the Parameters collection of the specified MySqlCommand object. This method is not currently supported since stored procedures are not available in MySql.

Overload List

Retrieves parameter information from the stored procedure specified in the MySqlCommand and populates the Parameters collection of the specified MySqlCommand object. This method is not currently supported since stored procedures are not available in MySql.

See Also

MySqlCommandBuilder Class, MySql.Data.MySqlClient Namespace

MySqlCommandBuilder.DeriveParameters Method

Retrieves parameter information from the stored procedure specified in the MySqlCommand and populates the Parameters collection of the specified MySqlCommand object. This method is not currently supported since stored procedures are not available in MySql.

Syntax: Visual Basic

Overloads Public Shared Sub DeriveParameters( _
 ByVal command As MySqlCommand _
)

Syntax: C#

public static void DeriveParameters(
MySqlCommandcommand
);

Parameters

Exceptions

Exception Type Condition
InvalidOperationException The command text is not a valid stored procedure name.

See Also

MySqlCommandBuilder Class, MySql.Data.MySqlClient Namespace, MySqlCommandBuilder.DeriveParameters Overload List

MySqlCommandBuilder.DeriveParameters Method

Syntax: Visual Basic

Overloads Public Shared Sub DeriveParameters( _
 ByVal command As MySqlCommand, _
 ByVal useProc As Boolean _
)

Syntax: C#

public static void DeriveParameters(
MySqlCommandcommand,
booluseProc
);

See Also

MySqlCommandBuilder Class, MySql.Data.MySqlClient Namespace, MySqlCommandBuilder.DeriveParameters Overload List

MySqlCommandBuilder Constructor
MySqlCommandBuilder Constructor
MySqlCommandBuilder Constructor
MySqlCommandBuilder Constructor
MySqlCommandBuilder Constructor

Initializes a new instance of the MySqlCommandBuilder class.

Overload List

Initializes a new instance of the MySqlCommandBuilder class.

See Also

MySqlCommandBuilder Class, MySql.Data.MySqlClient Namespace

MySqlCommandBuilder Constructor

Initializes a new instance of the MySqlCommandBuilder class.

Syntax: Visual Basic

Overloads Public Sub New()

Syntax: C#

public MySqlCommandBuilder();

See Also

MySqlCommandBuilder Class, MySql.Data.MySqlClient Namespace, MySqlCommandBuilder Constructor Overload List

MySqlCommandBuilder Constructor
MySqlDataAdapter Class

Syntax: Visual Basic

Overloads Public Sub New( _
 ByVal adapter As MySqlDataAdapter _
)

Syntax: C#

public MySqlCommandBuilder(
MySqlDataAdapteradapter
);

See Also

MySqlCommandBuilder Class, MySql.Data.MySqlClient Namespace, MySqlCommandBuilder Constructor Overload List

MySqlDataAdapter Class
MySqlDataAdapter Members

For a list of all members of this type, see MySqlDataAdapter Members .

Syntax: Visual Basic

NotInheritable Public Class MySqlDataAdapter_
 Inherits DbDataAdapter

Syntax: C#

public sealed class MySqlDataAdapter : DbDataAdapter

Thread Safety

Public static (Shared in Visual Basic) members of this type are safe for multithreaded operations. Instance members are not guaranteed to be thread-safe.

Requirements

Namespace: MySql.Data.MySqlClient

Assembly: MySql.Data (in MySql.Data.dll)

See Also

MySqlDataAdapter Members, MySql.Data.MySqlClient Namespace

MySqlDataAdapter Members

MySqlDataAdapter overview

Public Instance Constructors

MySqlDataAdapter Overloaded. Initializes a new instance of the MySqlDataAdapter class.

Public Instance Properties

AcceptChangesDuringFill (inherited from DataAdapter) Gets or sets a value indicating whether AcceptChangesis called on a DataRowafter it is added to the DataTableduring any of the Fill operations.
AcceptChangesDuringUpdate (inherited from DataAdapter) Gets or sets whether AcceptChangesis called during a Update.
Container (inherited from Component) Gets the IContainer that contains the Component.
ContinueUpdateOnError (inherited from DataAdapter) Gets or sets a value that specifies whether to generate an exception when an error is encountered during a row update.
DeleteCommand Overloaded.
FillLoadOption (inherited from DataAdapter) Gets or sets the LoadOption that determines how the adapter fills the DataTablefrom the DbDataReader.
InsertCommand Overloaded.
MissingMappingAction (inherited from DataAdapter) Determines the action to take when incoming data does not have a matching table or column.
MissingSchemaAction (inherited from DataAdapter) Determines the action to take when existing DataSetschema does not match incoming data.
ReturnProviderSpecificTypes (inherited from DataAdapter) Gets or sets whether the Fillmethod should return provider-specific values or common CLS-compliant values.
SelectCommand Overloaded.
Site (inherited from Component) Gets or sets the ISite of the Component.
TableMappings (inherited from DataAdapter) Gets a collection that provides the master mapping between a source table and a DataTable.
UpdateBatchSize (inherited from DbDataAdapter) Gets or sets a value that enables or disables batch processing support, and specifies the number of commands that can be executed in a batch.
UpdateCommand Overloaded.

Public Instance Methods

CreateObjRef (inherited from MarshalByRefObject) Creates an object that contains all the relevant information required to generate a proxy used to communicate with a remote object.
Dispose (inherited from Component) Releases all resources used by the Component.
Equals (inherited from Object) Determines whether the specified Object is equal to the current Object.
Fill (inherited from DbDataAdapter) Overloaded. Adds or refreshes rows in the DataSetto match those in the data source using the DataSetname, and creates a DataTablenamed 'Table.'
FillSchema (inherited from DbDataAdapter) Overloaded. Configures the schema of the specified DataTablebased on the specified SchemaType.
GetFillParameters (inherited from DbDataAdapter) Gets the parameters set by the user when executing an SQL SELECT statement.
GetHashCode (inherited from Object) Serves as a hash function for a particular type. GetHashCode is suitable for use in hashing algorithms and data structures like a hash table.
GetLifetimeService (inherited from MarshalByRefObject) Retrieves the current lifetime service object that controls the lifetime policy for this instance.
GetType (inherited from Object) Gets the Type of the current instance.
InitializeLifetimeService (inherited from MarshalByRefObject) Obtains a lifetime service object to control the lifetime policy for this instance.
ResetFillLoadOption (inherited from DataAdapter) Resets FillLoadOptionto its default state and causes Fillto honor AcceptChangesDuringFill.
ShouldSerializeAcceptChangesDuringFill (inherited from DataAdapter) Determines whether the AcceptChangesDuringFillproperty should be persisted.
ShouldSerializeFillLoadOption (inherited from DataAdapter) Determines whether the FillLoadOptionproperty should be persisted.
ToString (inherited from Component) Returns a String containing the name of the Component, if any. This method should not be overridden.
Update (inherited from DbDataAdapter) Overloaded. Calls the respective INSERT, UPDATE, or DELETE statements for each inserted, updated, or deleted row in the specified DataSet.

Public Instance Events

Disposed (inherited from Component) Adds an event handler to listen to the Disposed event on the component.
FillError (inherited from DataAdapter) Returned when an error occurs during a fill operation.
RowUpdated Occurs during Update after a command is executed against the data source. The attempt to update is made, so the event fires.
RowUpdating Occurs during Update before a command is executed against the data source. The attempt to update is made, so the event fires.

Protected Internal Instance Properties

FillCommandBehavior (inherited from DbDataAdapter) Gets or sets the behavior of the command used to fill the data adapter.

See Also

MySqlDataAdapter Class, MySql.Data.MySqlClient Namespace

MySqlDataAdapter Constructor

Initializes a new instance of the MySqlDataAdapter class.

Overload List

Initializes a new instance of the MySqlDataAdapter class.

See Also

MySqlDataAdapter Class, MySql.Data.MySqlClient Namespace

MySqlDataAdapter Constructor

Initializes a new instance of the MySqlDataAdapter class.

Syntax: Visual Basic

Overloads Public Sub New()

Syntax: C#

public MySqlDataAdapter();

See Also

MySqlDataAdapter Class, MySql.Data.MySqlClient Namespace, MySqlDataAdapter Constructor Overload List

MySqlDataAdapter Constructor

Syntax: Visual Basic

Overloads Public Sub New( _
 ByVal selectCommand As MySqlCommand _
)

Syntax: C#

public MySqlDataAdapter(
MySqlCommandselectCommand
);

See Also

MySqlDataAdapter Class, MySql.Data.MySqlClient Namespace, MySqlDataAdapter Constructor Overload List

MySqlDataAdapter Constructor

Syntax: Visual Basic

Overloads Public Sub New( _
 ByVal selectCommandText As String, _
 ByVal connection As MySqlConnection _
)

Syntax: C#

public MySqlDataAdapter(
stringselectCommandText,
MySqlConnectionconnection
);

See Also

MySqlDataAdapter Class, MySql.Data.MySqlClient Namespace, MySqlDataAdapter Constructor Overload List

MySqlDataAdapter Constructor

Syntax: Visual Basic

Overloads Public Sub New( _
 ByVal selectCommandText As String, _
 ByVal selectConnString As String _
)

Syntax: C#

public MySqlDataAdapter(
stringselectCommandText,
stringselectConnString
);

See Also

MySqlDataAdapter Class, MySql.Data.MySqlClient Namespace, MySqlDataAdapter Constructor Overload List

DeleteCommand Property

Syntax: Visual Basic

Overloads Public Property DeleteCommand As MySqlCommand

Syntax: C#

new public MySqlCommand DeleteCommand {get; set;}

See Also

MySqlDataAdapter Class, MySql.Data.MySqlClient Namespace

InsertCommand Property

Syntax: Visual Basic

Overloads Public Property InsertCommand As MySqlCommand

Syntax: C#

new public MySqlCommand InsertCommand {get; set;}

See Also

MySqlDataAdapter Class, MySql.Data.MySqlClient Namespace

SelectCommand Property

Syntax: Visual Basic

Overloads Public Property SelectCommand As MySqlCommand

Syntax: C#

new public MySqlCommand SelectCommand {get; set;}

See Also

MySqlDataAdapter Class, MySql.Data.MySqlClient Namespace

UpdateCommand Property

Syntax: Visual Basic

Overloads Public Property UpdateCommand As MySqlCommand

Syntax: C#

new public MySqlCommand UpdateCommand {get; set;}

See Also

MySqlDataAdapter Class, MySql.Data.MySqlClient Namespace

MySqlDataAdapter.RowUpdated Event

Occurs during Update after a command is executed against the data source. The attempt to update is made, so the event fires.

Syntax: Visual Basic

Public Event RowUpdated As MySqlRowUpdatedEventHandler

Syntax: C#

public event MySqlRowUpdatedEventHandler RowUpdated;

Event Data

The event handler receives an argument of type MySqlRowUpdatedEventArgs containing data related to this event. The following MySqlRowUpdatedEventArgsproperties provide information specific to this event.

Property Description
Command Gets or sets the MySqlCommand executed when Update is called.
Errors Gets any errors generated by the .NET Framework data provider when the Commandwas executed.
RecordsAffected Gets the number of rows changed, inserted, or deleted by execution of the SQL statement.
Row Gets the DataRowsent through an Update.
RowCount Gets the number of rows processed in a batch of updated records.
StatementType Gets the type of SQL statement executed.
Status Gets the UpdateStatus of the Commandproperty.
TableMapping Gets the DataTableMappingsent through an Update.

See Also

MySqlDataAdapter Class, MySql.Data.MySqlClient Namespace

MySqlRowUpdatedEventHandler Delegate

Represents the method that will handle the RowUpdatedevent of a MySqlDataAdapter.

Syntax: Visual Basic

Public Delegate Sub MySqlRowUpdatedEventHandler( _
 ByVal sender As Object, _
 ByVal e As MySqlRowUpdatedEventArgs _
)

Syntax: C#

public delegate void MySqlRowUpdatedEventHandler(
objectsender,
MySqlRowUpdatedEventArgs
);

Requirements

Namespace: MySql.Data.MySqlClient

Assembly: MySql.Data (in MySql.Data.dll)

See Also

MySql.Data.MySqlClient Namespace

MySqlRowUpdatedEventArgs Class

Provides data for the RowUpdated event. This class cannot be inherited.

For a list of all members of this type, see MySqlRowUpdatedEventArgs Members .

Syntax: Visual Basic

NotInheritable Public Class MySqlRowUpdatedEventArgs_
 Inherits RowUpdatedEventArgs

Syntax: C#

public sealed class MySqlRowUpdatedEventArgs : RowUpdatedEventArgs

Thread Safety

Public static (Shared in Visual Basic) members of this type are safe for multithreaded operations. Instance members are not guaranteed to be thread-safe.

Requirements

Namespace: MySql.Data.MySqlClient

Assembly: MySql.Data (in MySql.Data.dll)

See Also

MySqlRowUpdatedEventArgs Members, MySql.Data.MySqlClient Namespace

MySqlRowUpdatedEventArgs Members

MySqlRowUpdatedEventArgs overview

Public Instance Constructors

MySqlRowUpdatedEventArgs Constructor Initializes a new instance of the MySqlRowUpdatedEventArgs class.

Public Instance Properties

Command Overloaded. Gets or sets the MySqlCommand executed when Update is called.
Errors (inherited from RowUpdatedEventArgs) Gets any errors generated by the .NET Framework data provider when the Commandwas executed.
RecordsAffected (inherited from RowUpdatedEventArgs) Gets the number of rows changed, inserted, or deleted by execution of the SQL statement.
Row (inherited from RowUpdatedEventArgs) Gets the DataRowsent through an Update.
RowCount (inherited from RowUpdatedEventArgs) Gets the number of rows processed in a batch of updated records.
StatementType (inherited from RowUpdatedEventArgs) Gets the type of SQL statement executed.
Status (inherited from RowUpdatedEventArgs) Gets the UpdateStatus of the Commandproperty.
TableMapping (inherited from RowUpdatedEventArgs) Gets the DataTableMappingsent through an Update.

Public Instance Methods

CopyToRows (inherited from RowUpdatedEventArgs) Overloaded. Copies references to the modified rows into the provided array.
Equals (inherited from Object) Determines whether the specified Object is equal to the current Object.
GetHashCode (inherited from Object) Serves as a hash function for a particular type. GetHashCode is suitable for use in hashing algorithms and data structures like a hash table.
GetType (inherited from Object) Gets the Type of the current instance.
ToString (inherited from Object) Returns a String that represents the current Object.

See Also

MySqlRowUpdatedEventArgs Class, MySql.Data.MySqlClient Namespace

MySqlRowUpdatedEventArgs Constructor

Initializes a new instance of the MySqlRowUpdatedEventArgs class.

Syntax: Visual Basic

Public Sub New( _
 ByVal row As DataRow, _
 ByVal command As IDbCommand, _
 ByVal statementType As StatementType, _
 ByVal tableMapping As DataTableMapping _
)

Syntax: C#

public MySqlRowUpdatedEventArgs(
DataRowrow,
IDbCommandcommand,
StatementTypestatementType,
DataTableMappingtableMapping
);

Parameters

See Also

MySqlRowUpdatedEventArgs Class, MySql.Data.MySqlClient Namespace

Command Property

Gets or sets the MySqlCommand executed when Update is called.

Syntax: Visual Basic

Overloads Public ReadOnly Property Command As MySqlCommand

Syntax: C#

new public MySqlCommand Command {get;}

See Also

MySqlRowUpdatedEventArgs Class, MySql.Data.MySqlClient Namespace

MySqlDataAdapter.RowUpdating Event

Occurs during Update before a command is executed against the data source. The attempt to update is made, so the event fires.

Syntax: Visual Basic

Public Event RowUpdating As MySqlRowUpdatingEventHandler

Syntax: C#

public event MySqlRowUpdatingEventHandler RowUpdating;

Event Data

The event handler receives an argument of type MySqlRowUpdatingEventArgs containing data related to this event. The following MySqlRowUpdatingEventArgsproperties provide information specific to this event.

Property Description
Command Gets or sets the MySqlCommand to execute when performing the Update.
Errors Gets any errors generated by the .NET Framework data provider when the Command executes.
Row Gets the DataRow that will be sent to the server as part of an insert, update, or delete operation.
StatementType Gets the type of SQL statement to execute.
Status Gets or sets the UpdateStatus of the Commandproperty.
TableMapping Gets the DataTableMapping to send through the Update.

See Also

MySqlDataAdapter Class, MySql.Data.MySqlClient Namespace

MySqlRowUpdatingEventHandler Delegate

Represents the method that will handle the RowUpdatingevent of a MySqlDataAdapter.

Syntax: Visual Basic

Public Delegate Sub MySqlRowUpdatingEventHandler( _
 ByVal sender As Object, _
 ByVal e As MySqlRowUpdatingEventArgs _
)

Syntax: C#

public delegate void MySqlRowUpdatingEventHandler(
objectsender,
MySqlRowUpdatingEventArgs
);

Requirements

Namespace: MySql.Data.MySqlClient

Assembly: MySql.Data (in MySql.Data.dll)

See Also

MySql.Data.MySqlClient Namespace

MySqlRowUpdatingEventArgs Class

Provides data for the RowUpdating event. This class cannot be inherited.

For a list of all members of this type, see MySqlRowUpdatingEventArgs Members .

Syntax: Visual Basic

NotInheritable Public Class MySqlRowUpdatingEventArgs_
 Inherits RowUpdatingEventArgs

Syntax: C#

public sealed class MySqlRowUpdatingEventArgs : RowUpdatingEventArgs

Thread Safety

Public static (Shared in Visual Basic) members of this type are safe for multithreaded operations. Instance members are not guaranteed to be thread-safe.

Requirements

Namespace: MySql.Data.MySqlClient

Assembly: MySql.Data (in MySql.Data.dll)

See Also

MySqlRowUpdatingEventArgs Members, MySql.Data.MySqlClient Namespace

MySqlRowUpdatingEventArgs Members

MySqlRowUpdatingEventArgs overview

Public Instance Constructors

MySqlRowUpdatingEventArgs Constructor Initializes a new instance of the MySqlRowUpdatingEventArgs class.

Public Instance Properties

Command Overloaded. Gets or sets the MySqlCommand to execute when performing the Update.
Errors (inherited from RowUpdatingEventArgs) Gets any errors generated by the .NET Framework data provider when the Command executes.
Row (inherited from RowUpdatingEventArgs) Gets the DataRow that will be sent to the server as part of an insert, update, or delete operation.
StatementType (inherited from RowUpdatingEventArgs) Gets the type of SQL statement to execute.
Status (inherited from RowUpdatingEventArgs) Gets or sets the UpdateStatus of the Commandproperty.
TableMapping (inherited from RowUpdatingEventArgs) Gets the DataTableMapping to send through the Update.

Public Instance Methods

Equals (inherited from Object) Determines whether the specified Object is equal to the current Object.
GetHashCode (inherited from Object) Serves as a hash function for a particular type. GetHashCode is suitable for use in hashing algorithms and data structures like a hash table.
GetType (inherited from Object) Gets the Type of the current instance.
ToString (inherited from Object) Returns a String that represents the current Object.

See Also

MySqlRowUpdatingEventArgs Class, MySql.Data.MySqlClient Namespace

MySqlRowUpdatingEventArgs Constructor

Initializes a new instance of the MySqlRowUpdatingEventArgs class.

Syntax: Visual Basic

Public Sub New( _
 ByVal row As DataRow, _
 ByVal command As IDbCommand, _
 ByVal statementType As StatementType, _
 ByVal tableMapping As DataTableMapping _
)

Syntax: C#

public MySqlRowUpdatingEventArgs(
DataRowrow,
IDbCommandcommand,
StatementTypestatementType,
DataTableMappingtableMapping
);

Parameters

See Also

MySqlRowUpdatingEventArgs Class, MySql.Data.MySqlClient Namespace

Command Property

Gets or sets the MySqlCommand to execute when performing the Update.

Syntax: Visual Basic

Overloads Public Property Command As MySqlCommand

Syntax: C#

new public MySqlCommand Command {get; set;}

See Also

MySqlRowUpdatingEventArgs Class, MySql.Data.MySqlClient Namespace

MySqlCommandBuilder Constructor

Syntax: Visual Basic

Overloads Public Sub New( _
 ByVal adapter As MySqlDataAdapter, _
 ByVal lastOneWins As Boolean _
)

Syntax: C#

public MySqlCommandBuilder(
MySqlDataAdapteradapter,
boollastOneWins
);

See Also

MySqlCommandBuilder Class, MySql.Data.MySqlClient Namespace, MySqlCommandBuilder Constructor Overload List

MySqlCommandBuilder Constructor

Syntax: Visual Basic

Overloads Public Sub New( _
 ByVal lastOneWins As Boolean _
)

Syntax: C#

public MySqlCommandBuilder(
boollastOneWins
);

See Also

MySqlCommandBuilder Class, MySql.Data.MySqlClient Namespace, MySqlCommandBuilder Constructor Overload List

DataAdapter Property

Syntax: Visual Basic

Public Property DataAdapter As MySqlDataAdapter

Syntax: C#

public MySqlDataAdapter DataAdapter {get; set;}

See Also

MySqlCommandBuilder Class, MySql.Data.MySqlClient Namespace

QuotePrefix Property

Syntax: Visual Basic

Public Property QuotePrefix As String

Syntax: C#

public string QuotePrefix {get; set;}

See Also

MySqlCommandBuilder Class, MySql.Data.MySqlClient Namespace

QuoteSuffix Property

Syntax: Visual Basic

Public Property QuoteSuffix As String

Syntax: C#

public string QuoteSuffix {get; set;}

See Also

MySqlCommandBuilder Class, MySql.Data.MySqlClient Namespace

MySqlCommandBuilder.GetDeleteCommand Method

Syntax: Visual Basic

Public Function GetDeleteCommand() As MySqlCommand

Syntax: C#

public MySqlCommand GetDeleteCommand();

See Also

MySqlCommandBuilder Class, MySql.Data.MySqlClient Namespace

MySqlCommandBuilder.GetInsertCommand Method

Syntax: Visual Basic

Public Function GetInsertCommand() As MySqlCommand

Syntax: C#

public MySqlCommand GetInsertCommand();

See Also

MySqlCommandBuilder Class, MySql.Data.MySqlClient Namespace

MySqlCommandBuilder.GetUpdateCommand Method

Syntax: Visual Basic

Public Function GetUpdateCommand() As MySqlCommand

Syntax: C#

public MySqlCommand GetUpdateCommand();

See Also

MySqlCommandBuilder Class, MySql.Data.MySqlClient Namespace

MySqlCommandBuilder.RefreshSchema Method

Syntax: Visual Basic

Public Sub RefreshSchema()

Syntax: C#

public void RefreshSchema();

See Also

MySqlCommandBuilder Class, MySql.Data.MySqlClient Namespace

MySqlException Class
MySqlException Members

The exception that is thrown when MariaDB returns an error. This class cannot be inherited.

For a list of all members of this type, see MySqlException Members .

Syntax: Visual Basic

NotInheritable Public Class MySqlException_
 Inherits SystemException

Syntax: C#

public sealed class MySqlException : SystemException

Thread Safety

Public static (Shared in Visual Basic) members of this type are safe for multithreaded operations. Instance members are not guaranteed to be thread-safe.

Requirements

Namespace: MySql.Data.MySqlClient

Assembly: MySql.Data (in MySql.Data.dll)

See Also

MySqlException Members, MySql.Data.MySqlClient Namespace

MySqlException Members
Number Property

MySqlException overview

Public Instance Properties

Data (inherited from Exception) Gets a collection of key/value pairs that provide additional, user-defined information about the exception.
HelpLink (inherited from Exception) Gets or sets a link to the help file associated with this exception.
InnerException (inherited from Exception) Gets the Exceptioninstance that caused the current exception.
Message (inherited from Exception) Gets a message that describes the current exception.
Number Gets a number that identifies the type of error. This number corresponds to the error numbers given in "Server Error Codes and Messages".
Source (inherited from Exception) Gets or sets the name of the application or the object that causes the error.
StackTrace (inherited from Exception) Gets a string representation of the frames on the call stack at the time the current exception was thrown.
TargetSite (inherited from Exception) Gets the method that throws the current exception.

Public Instance Methods

Equals (inherited from Object) Determines whether the specified Object is equal to the current Object.
GetBaseException (inherited from Exception) When overridden in a derived class, returns the Exception that is the root cause of one or more subsequent exceptions.
GetHashCode (inherited from Object) Serves as a hash function for a particular type. GetHashCode is suitable for use in hashing algorithms and data structures like a hash table.
GetObjectData (inherited from Exception) When overridden in a derived class, sets the SerializationInfo with information about the exception.
GetType (inherited from Exception) Gets the runtime type of the current instance.
ToString (inherited from Exception) Creates and returns a string representation of the current exception.

See Also

MySqlException Class, MySql.Data.MySqlClient Namespace

Number Property

Gets a number that identifies the type of error.

Syntax: Visual Basic

Public ReadOnly Property Number As Integer

Syntax: C#

public int Number {get;}

See Also

MySqlException Class, MySql.Data.MySqlClient Namespace

MySqlHelper Class
MySqlHelper Members

Helper class that makes it easier to work with the provider.

For a list of all members of this type, see MySqlHelper Members .

Syntax: Visual Basic

NotInheritable Public Class MySqlHelper

Syntax: C#

public sealed class MySqlHelper

Thread Safety

Public static (Shared in Visual Basic) members of this type are safe for multithreaded operations. Instance members are not guaranteed to be thread-safe.

Requirements

Namespace: MySql.Data.MySqlClient

Assembly: MySql.Data (in MySql.Data.dll)

See Also

MySqlHelper Members, MySql.Data.MySqlClient Namespace

MySqlHelper Members
MySqlHelper.ExecuteDataRow Method
ExecuteDataset Method
ExecuteNonQuery Method
ExecuteReader Method
ExecuteScalar Method
MySqlHelper.UpdateDataSet Method

MySqlHelper overview

Public Static (Shared) Methods

ExecuteDataRow Executes a single SQL statement and returns the first row of the resultset. A new MySqlConnection object is created, opened, and closed during this method.
ExecuteDataset Overloaded. Executes a single SQL statement and returns the resultset in a DataSet. A new MySqlConnection object is created, opened, and closed during this method.
ExecuteNonQuery Overloaded. Executes a single command against a MariaDB database. The MySqlConnection is assumed to be open when the method is called and remains open after the method completes.
ExecuteReader Overloaded. Executes a single command against a MariaDB database.
ExecuteScalar Overloaded. Execute a single command against a MariaDB database.
UpdateDataSet Updates the given table with data from the given DataSet

Public Instance Methods

Equals (inherited from Object) Determines whether the specified Object is equal to the current Object.
GetHashCode (inherited from Object) Serves as a hash function for a particular type. GetHashCode is suitable for use in hashing algorithms and data structures like a hash table.
GetType (inherited from Object) Gets the Type of the current instance.
ToString (inherited from Object) Returns a String that represents the current Object.

See Also

MySqlHelper Class, MySql.Data.MySqlClient Namespace

MySqlHelper.ExecuteDataRow Method

Executes a single SQL statement and returns the first row of the resultset. A new MySqlConnection object is created, opened, and closed during this method.

Syntax: Visual Basic

Public Shared Function ExecuteDataRow( _
 ByVal connectionString As String, _
 ByVal commandText As String, _
 ParamArray parms As MySqlParameter() _
) As DataRow

Syntax: C#

public static DataRow ExecuteDataRow(
stringconnectionString,
stringcommandText,
 params MySqlParameter[]parms
);

Parameters

Return Value

DataRow containing the first row of the resultset

See Also

MySqlHelper Class, MySql.Data.MySqlClient Namespace

ExecuteDataset Method
MySqlHelper.ExecuteDataset Method
MySqlHelper.ExecuteDataset Method
MySqlHelper.ExecuteDataset Method
MySqlHelper.ExecuteDataset Method

Executes a single SQL statement and returns the resultset in a DataSet. The state of the MySqlConnection object remains unchanged after execution of this method.

Overload List

Executes a single SQL statement and returns the resultset in a DataSet. The state of the MySqlConnection object remains unchanged after execution of this method.

Executes a single SQL statement and returns the resultset in a DataSet. The state of the MySqlConnection object remains unchanged after execution of this method.

Executes a single SQL statement and returns the resultset in a DataSet. A new MySqlConnection object is created, opened, and closed during this method.

Executes a single SQL statement and returns the resultset in a DataSet. A new MySqlConnection object is created, opened, and closed during this method.

See Also

MySqlHelper Class, MySql.Data.MySqlClient Namespace

MySqlHelper.ExecuteDataset Method

Executes a single SQL statement and returns the resultset in a DataSet. The state of the MySqlConnection object remains unchanged after execution of this method.

Syntax: Visual Basic

Overloads Public Shared Function ExecuteDataset( _
 ByVal connection As MySqlConnection, _
 ByVal commandText As String _
) As DataSet

Syntax: C#

public static DataSet ExecuteDataset(
MySqlConnectionconnection,
stringcommandText
);

Parameters

Return Value

DataSetcontaining the resultset

See Also

MySqlHelper Class, MySql.Data.MySqlClient Namespace, MySqlHelper.ExecuteDataset Overload List

MySqlHelper.ExecuteDataset Method

Executes a single SQL statement and returns the resultset in a DataSet. The state of the MySqlConnection object remains unchanged after execution of this method.

Syntax: Visual Basic

Overloads Public Shared Function ExecuteDataset( _
 ByVal connection As MySqlConnection, _
 ByVal commandText As String, _
 ParamArray commandParameters As MySqlParameter() _
) As DataSet

Syntax: C#

public static DataSet ExecuteDataset(
MySqlConnectionconnection,
stringcommandText,
 params MySqlParameter[]commandParameters
);

Parameters

Return Value

DataSetcontaining the resultset

See Also

MySqlHelper Class, MySql.Data.MySqlClient Namespace, MySqlHelper.ExecuteDataset Overload List

MySqlHelper.ExecuteDataset Method

Executes a single SQL statement and returns the resultset in a DataSet. A new MySqlConnection object is created, opened, and closed during this method.

Syntax: Visual Basic

Overloads Public Shared Function ExecuteDataset( _
 ByVal connectionString As String, _
 ByVal commandText As String _
) As DataSet

Syntax: C#

public static DataSet ExecuteDataset(
stringconnectionString,
stringcommandText
);

Parameters

Return Value

DataSetcontaining the resultset

See Also

MySqlHelper Class, MySql.Data.MySqlClient Namespace, MySqlHelper.ExecuteDataset Overload List

MySqlHelper.ExecuteDataset Method

Executes a single SQL statement and returns the resultset in a DataSet. A new MySqlConnection object is created, opened, and closed during this method.

Syntax: Visual Basic

Overloads Public Shared Function ExecuteDataset( _
 ByVal connectionString As String, _
 ByVal commandText As String, _
 ParamArray commandParameters As MySqlParameter() _
) As DataSet

Syntax: C#

public static DataSet ExecuteDataset(
stringconnectionString,
stringcommandText,
 params MySqlParameter[]commandParameters
);

Parameters

Return Value

DataSetcontaining the resultset

See Also

MySqlHelper Class, MySql.Data.MySqlClient Namespace, MySqlHelper.ExecuteDataset Overload List

ExecuteNonQuery Method
MySqlHelper.ExecuteNonQuery Method
MySqlHelper.ExecuteNonQuery Method

Executes a single command against a MariaDB database. The MySqlConnection is assumed to be open when the method is called and remains open after the method completes.

Overload List

Executes a single command against a MariaDB database. The MySqlConnection is assumed to be open when the method is called and remains open after the method completes.

Executes a single command against a MariaDB database. A new MySqlConnection is created using the ConnectionString given.

See Also

MySqlHelper Class, MySql.Data.MySqlClient Namespace

MySqlHelper.ExecuteNonQuery Method

Executes a single command against a MariaDB database. The MySqlConnection is assumed to be open when the method is called and remains open after the method completes.

Syntax: Visual Basic

Overloads Public Shared Function ExecuteNonQuery( _
 ByVal connection As MySqlConnection, _
 ByVal commandText As String, _
 ParamArray commandParameters As MySqlParameter() _
) As Integer

Syntax: C#

public static int ExecuteNonQuery(
MySqlConnectionconnection,
stringcommandText,
 params MySqlParameter[]commandParameters
);

Parameters

Return Value

See Also

MySqlHelper Class, MySql.Data.MySqlClient Namespace, MySqlHelper.ExecuteNonQuery Overload List

MySqlHelper.ExecuteNonQuery Method

Executes a single command against a MariaDB database. A new MySqlConnection is created using the ConnectionString given.

Syntax: Visual Basic

Overloads Public Shared Function ExecuteNonQuery( _
 ByVal connectionString As String, _
 ByVal commandText As String, _
 ParamArray parms As MySqlParameter() _
) As Integer

Syntax: C#

public static int ExecuteNonQuery(
stringconnectionString,
stringcommandText,
 params MySqlParameter[]parms
);

Parameters

Return Value

See Also

MySqlHelper Class, MySql.Data.MySqlClient Namespace, MySqlHelper.ExecuteNonQuery Overload List

ExecuteReader Method
MySqlHelper.ExecuteReader Method
MySqlHelper.ExecuteReader Method

Executes a single command against a MariaDB database.

Overload List

Executes a single command against a MariaDB database.

Executes a single command against a MariaDB database.

See Also

MySqlHelper Class, MySql.Data.MySqlClient Namespace

MySqlHelper.ExecuteReader Method

Executes a single command against a MariaDB database.

Syntax: Visual Basic

Overloads Public Shared Function ExecuteReader( _
 ByVal connectionString As String, _
 ByVal commandText As String _
) As MySqlDataReader

Syntax: C#

public static MySqlDataReader ExecuteReader(
stringconnectionString,
stringcommandText
);

Parameters

Return Value

MySqlDataReader object ready to read the results of the command

See Also

MySqlHelper Class, MySql.Data.MySqlClient Namespace, MySqlHelper.ExecuteReader Overload List

MySqlHelper.ExecuteReader Method

Executes a single command against a MariaDB database.

Syntax: Visual Basic

Overloads Public Shared Function ExecuteReader( _
 ByVal connectionString As String, _
 ByVal commandText As String, _
 ParamArray commandParameters As MySqlParameter() _
) As MySqlDataReader

Syntax: C#

public static MySqlDataReader ExecuteReader(
stringconnectionString,
stringcommandText,
 params MySqlParameter[]commandParameters
);

Parameters

Return Value

MySqlDataReader object ready to read the results of the command

See Also

MySqlHelper Class, MySql.Data.MySqlClient Namespace, MySqlHelper.ExecuteReader Overload List

ExecuteScalar Method
MySqlHelper.ExecuteScalar Method
MySqlHelper.ExecuteScalar Method
MySqlHelper.ExecuteScalar Method
MySqlHelper.ExecuteScalar Method

Execute a single command against a MariaDB database.

Overload List

Execute a single command against a MariaDB database.

Execute a single command against a MariaDB database.

Execute a single command against a MariaDB database.

Execute a single command against a MariaDB database.

See Also

MySqlHelper Class, MySql.Data.MySqlClient Namespace

MySqlHelper.ExecuteScalar Method

Execute a single command against a MariaDB database.

Syntax: Visual Basic

Overloads Public Shared Function ExecuteScalar( _
 ByVal connection As MySqlConnection, _
 ByVal commandText As String _
) As Object

Syntax: C#

public static object ExecuteScalar(
MySqlConnectionconnection,
stringcommandText
);

Parameters

Return Value

The first column of the first row in the result set, or a null reference if the result set is empty.

See Also

MySqlHelper Class, MySql.Data.MySqlClient Namespace, MySqlHelper.ExecuteScalar Overload List

MySqlHelper.ExecuteScalar Method

Execute a single command against a MariaDB database.

Syntax: Visual Basic

Overloads Public Shared Function ExecuteScalar( _
 ByVal connection As MySqlConnection, _
 ByVal commandText As String, _
 ParamArray commandParameters As MySqlParameter() _
) As Object

Syntax: C#

public static object ExecuteScalar(
MySqlConnectionconnection,
stringcommandText,
 params MySqlParameter[]commandParameters
);

Parameters

Return Value

The first column of the first row in the result set, or a null reference if the result set is empty.

See Also

MySqlHelper Class, MySql.Data.MySqlClient Namespace, MySqlHelper.ExecuteScalar Overload List

MySqlHelper.ExecuteScalar Method

Execute a single command against a MariaDB database.

Syntax: Visual Basic

Overloads Public Shared Function ExecuteScalar( _
 ByVal connectionString As String, _
 ByVal commandText As String _
) As Object

Syntax: C#

public static object ExecuteScalar(
stringconnectionString,
stringcommandText
);

Parameters

Return Value

The first column of the first row in the result set, or a null reference if the result set is empty.

See Also

MySqlHelper Class, MySql.Data.MySqlClient Namespace, MySqlHelper.ExecuteScalar Overload List

MySqlHelper.ExecuteScalar Method

Execute a single command against a MariaDB database.

Syntax: Visual Basic

Overloads Public Shared Function ExecuteScalar( _
 ByVal connectionString As String, _
 ByVal commandText As String, _
 ParamArray commandParameters As MySqlParameter() _
) As Object

Syntax: C#

public static object ExecuteScalar(
stringconnectionString,
stringcommandText,
 params MySqlParameter[]commandParameters
);

Parameters

Return Value

The first column of the first row in the result set, or a null reference if the result set is empty.

See Also

MySqlHelper Class, MySql.Data.MySqlClient Namespace, MySqlHelper.ExecuteScalar Overload List

MySqlHelper.UpdateDataSet Method

Updates the given table with data from the given DataSet

Syntax: Visual Basic

Public Shared Sub UpdateDataSet( _
 ByVal connectionString As String, _
 ByVal commandText As String, _
 ByVal ds As DataSet, _
 ByVal tablename As String _
)

Syntax: C#

public static void UpdateDataSet(
stringconnectionString,
stringcommandText,
DataSetds,
stringtablename
);

Parameters

See Also

MySqlHelper Class, MySql.Data.MySqlClient Namespace

MySqlErrorCode Enumeration

Syntax: Visual Basic

Public Enum MySqlErrorCode

Syntax: C#

public enum MySqlErrorCode

Members

Member Name Description
PacketTooLarge
PasswordNotAllowed
DuplicateKeyEntry
HostNotPrivileged
PasswordNoMatch
AnonymousUser
DuplicateKey
KeyNotFound
DuplicateKeyName

Requirements

Namespace: MySql.Data.MySqlClient

Assembly: MySql.Data (in MySql.Data.dll)

See Also

MySql.Data.MySqlClient Namespace

MySql.Data.Types

MySql.Data.TypesHierarchy
MySqlConversionException Class
MySqlDateTime Class

Namespace hierarchy

Classes

Class Description
MySqlConversionException Summary description for MySqlConversionException.
MySqlDateTime Summary description for MySqlDateTime.
MySqlValue
MySql.Data.TypesHierarchy

See Also

MySql.Data.Types Namespace

MySqlConversionException Class
MySqlConversionException Members

Summary description for MySqlConversionException.

For a list of all members of this type, see MySqlConversionException Members .

Syntax: Visual Basic

Public Class MySqlConversionException_
 Inherits ApplicationException

Syntax: C#

public class MySqlConversionException : ApplicationException

Thread Safety

Public static (Shared in Visual Basic) members of this type are safe for multithreaded operations. Instance members are not guaranteed to be thread-safe.

Requirements

Namespace: MySql.Data.Types

Assembly: MySql.Data (in MySql.Data.dll)

See Also

MySqlConversionException Members, MySql.Data.Types Namespace

MySqlConversionException Members
MySqlConversionException Constructor

MySqlConversionException overview

Public Instance Constructors

MySqlConversionException Constructor Ctor

Public Instance Properties

Data (inherited from Exception) Gets a collection of key/value pairs that provide additional, user-defined information about the exception.
HelpLink (inherited from Exception) Gets or sets a link to the help file associated with this exception.
InnerException (inherited from Exception) Gets the Exceptioninstance that caused the current exception.
Message (inherited from Exception) Gets a message that describes the current exception.
Source (inherited from Exception) Gets or sets the name of the application or the object that causes the error.
StackTrace (inherited from Exception) Gets a string representation of the frames on the call stack at the time the current exception was thrown.
TargetSite (inherited from Exception) Gets the method that throws the current exception.

Public Instance Methods

Equals (inherited from Object) Determines whether the specified Object is equal to the current Object.
GetBaseException (inherited from Exception) When overridden in a derived class, returns the Exception that is the root cause of one or more subsequent exceptions.
GetHashCode (inherited from Object) Serves as a hash function for a particular type. GetHashCode is suitable for use in hashing algorithms and data structures like a hash table.
GetObjectData (inherited from Exception) When overridden in a derived class, sets the SerializationInfo with information about the exception.
GetType (inherited from Exception) Gets the runtime type of the current instance.
ToString (inherited from Exception) Creates and returns a string representation of the current exception.

Protected Instance Properties

HResult (inherited from Exception) Gets or sets HRESULT, a coded numeric value that is assigned to a specific exception.

Protected Instance Methods

Finalize (inherited from Object) Allows an Object to attempt to free resources and perform other cleanup operations before the Object is reclaimed by garbage collection.
MemberwiseClone (inherited from Object) Creates a shallow copy of the current Object.

See Also

MySqlConversionException Class, MySql.Data.Types Namespace

MySqlConversionException Constructor

Syntax: Visual Basic

Public Sub New( _
 ByVal msg As String _
)

Syntax: C#

public MySqlConversionException(
stringmsg
);

See Also

MySqlConversionException Class, MySql.Data.Types Namespace

MySqlDateTime Class
MySqlDateTime Members

Summary description for MySqlDateTime.

For a list of all members of this type, see MySqlDateTime Members .

Syntax: Visual Basic

Public Class MySqlDateTime_
 Inherits MySqlValue_
 Implements IConvertible, IComparable

Syntax: C#

public class MySqlDateTime : MySqlValue, IConvertible, IComparable

Thread Safety

Public static (Shared in Visual Basic) members of this type are safe for multithreaded operations. Instance members are not guaranteed to be thread-safe.

Requirements

Namespace: MySql.Data.Types

Assembly: MySql.Data (in MySql.Data.dll)

See Also

MySqlDateTime Members, MySql.Data.Types Namespace

MySqlDateTime Members
MySqlDateTime Explicit MySqlDateTime to DateTime Conversion
Day Property
Hour Property
IsNull Property
IsValidDateTime Property
Millisecond Property
Minute Property
Month Property
Second Property
Year Property
MySqlDateTime.GetDateTime Method
MySqlDateTime.ToString Method

MySqlDateTime overview

Public Static (Shared) Type Conversions

Explicit MySqlDateTime to DateTime Conversion

Public Instance Properties

Day Returns the day portion of this datetime
Hour Returns the hour portion of this datetime
IsNull (inherited from MySqlValue)
IsValidDateTime Indicates if this object contains a value that can be represented as a DateTime
Minute Returns the minute portion of this datetime
Month Returns the month portion of this datetime
Second Returns the second portion of this datetime
Millisecond Returns the millisecond portion of this datetime
ValueAsObject (inherited from MySqlValue) Returns the value of this field as an object
Year Returns the year portion of this datetime

Public Instance Methods

Equals (inherited from Object) Determines whether the specified Object is equal to the current Object.
GetDateTime Returns this value as a DateTime
GetHashCode (inherited from Object) Serves as a hash function for a particular type. GetHashCode is suitable for use in hashing algorithms and data structures like a hash table.
GetType (inherited from Object) Gets the Type of the current instance.
ToString Returns a MySQL-specific string representation of this value

Protected Instance Fields

classType (inherited from MySqlValue) The system type represented by this value
dbType (inherited from MySqlValue) The generic dbtype of this value
isNull (inherited from MySqlValue) Is this value null
mySqlDbType (inherited from MySqlValue) The specific MariaDB db type
mySqlTypeName (inherited from MySqlValue) The MySQL-specific typename of this value
objectValue (inherited from MySqlValue)

Protected Instance Methods

Finalize (inherited from Object) Allows an Object to attempt to free resources and perform other cleanup operations before the Object is reclaimed by garbage collection.
MemberwiseClone (inherited from Object) Creates a shallow copy of the current Object.

See Also

MySqlDateTime Class, MySql.Data.Types Namespace

MySqlDateTime Explicit MySqlDateTime to DateTime Conversion

Syntax: Visual Basic

MySqlDateTime.op_Explicit(val)

Syntax: C#

public static explicit operator DateTime(
MySqlDateTimeval
);

Parameters

Return Value

See Also

MySqlDateTime Class, MySql.Data.Types Namespace

Day Property

Returns the day portion of this datetime

Syntax: Visual Basic

Public Property Day As Integer

Syntax: C#

public int Day {get; set;}

See Also

MySqlDateTime Class, MySql.Data.Types Namespace

Hour Property

Returns the hour portion of this datetime

Syntax: Visual Basic

Public Property Hour As Integer

Syntax: C#

public int Hour {get; set;}

See Also

MySqlDateTime Class, MySql.Data.Types Namespace

IsNull Property
MySqlValue Class

Syntax: Visual Basic

Public Property IsNull As Boolean

Syntax: C#

public bool IsNull {get; set;}

See Also

MySqlValue Class, MySql.Data.Types Namespace

MySqlValue Class
MySqlValue Members

For a list of all members of this type, see MySqlValue Members .

Syntax: Visual Basic

MustInherit Public Class MySqlValue

Syntax: C#

public abstract class MySqlValue

Thread Safety

Public static (Shared in Visual Basic) members of this type are safe for multithreaded operations. Instance members are not guaranteed to be thread-safe.

Requirements

Namespace: MySql.Data.Types

Assembly: MySql.Data (in MySql.Data.dll)

See Also

MySqlValue Members, MySql.Data.Types Namespace

MySqlValue Members
MySqlValue.numberFormat Field
MySqlValue Constructor
ValueAsObject Property
MySqlValue.ToString Method
MySqlValue.classType Field
MySqlValue.dbType Field
MySqlValue.mySqlDbType Field
MySqlValue.mySqlTypeName Field
MySqlValue.objectValue Field

MySqlValue overview

Protected Static (Shared) Fields

numberFormat

Public Instance Constructors

MySqlValue Constructor Initializes a new instance of the MySqlValue class.

Public Instance Properties

IsNull
ValueAsObject Returns the value of this field as an object

Public Instance Methods

Equals (inherited from Object) Determines whether the specified Object is equal to the current Object.
GetHashCode (inherited from Object) Serves as a hash function for a particular type. GetHashCode is suitable for use in hashing algorithms and data structures like a hash table.
GetType (inherited from Object) Gets the Type of the current instance.
ToString Returns a string representation of this value

Protected Instance Fields

classType The system type represented by this value
dbType The generic dbtype of this value
isNull Is this value null
mySqlDbType The specific MariaDB db type
mySqlTypeName The MySQL-specific typename of this value
objectValue

Protected Instance Methods

Finalize (inherited from Object) Allows an Object to attempt to free resources and perform other cleanup operations before the Object is reclaimed by garbage collection.
MemberwiseClone (inherited from Object) Creates a shallow copy of the current Object.

See Also

MySqlValue Class, MySql.Data.Types Namespace

MySqlValue.numberFormat Field

Syntax: Visual Basic

Protected Shared numberFormat As NumberFormatInfo

Syntax: C#

protected static NumberFormatInfo numberFormat;

See Also

MySqlValue Class, MySql.Data.Types Namespace

MySqlValue Constructor

Initializes a new instance of the MySqlValue class.

Syntax: Visual Basic

Public Sub New()

Syntax: C#

public MySqlValue();

See Also

MySqlValue Class, MySql.Data.Types Namespace

ValueAsObject Property

Returns the value of this field as an object

Syntax: Visual Basic

Public ReadOnly Property ValueAsObject As Object

Syntax: C#

public object ValueAsObject {get;}

See Also

MySqlValue Class, MySql.Data.Types Namespace

MySqlValue.ToString Method

Returns a string representation of this value

Syntax: Visual Basic

Overrides Public Function ToString() As String

Syntax: C#

public override string ToString();

See Also

MySqlValue Class, MySql.Data.Types Namespace

MySqlValue.classType Field

The system type represented by this value

Syntax: Visual Basic

Protected classType As Type

Syntax: C#

protected Type classType;

See Also

MySqlValue Class, MySql.Data.Types Namespace

MySqlValue.dbType Field

The generic dbtype of this value

Syntax: Visual Basic

Protected dbType As DbType

Syntax: C#

protected DbType dbType;

See Also

MySqlValue Class, MySql.Data.Types Namespace

MySqlValue.mySqlDbType Field

The specific MariaDB db type

Syntax: Visual Basic

Protected mySqlDbType As MySqlDbType

Syntax: C#

protected MySqlDbType mySqlDbType;

See Also

MySqlValue Class, MySql.Data.Types Namespace

MySqlValue.mySqlTypeName Field

The MySQL-specific typename of this value

Syntax: Visual Basic

Protected mySqlTypeName As String

Syntax: C#

protected string mySqlTypeName;

See Also

MySqlValue Class, MySql.Data.Types Namespace

MySqlValue.objectValue Field

Syntax: Visual Basic

Protected objectValue As Object

Syntax: C#

protected object objectValue;

See Also

MySqlValue Class, MySql.Data.Types Namespace

IsValidDateTime Property

Indicates if this object contains a value that can be represented as a DateTime

Syntax: Visual Basic

Public ReadOnly Property IsValidDateTime As Boolean

Syntax: C#

public bool IsValidDateTime {get;}

See Also

MySqlDateTime Class, MySql.Data.Types Namespace

Millisecond Property

Returns the millisecond portion of this datetime

Syntax: Visual Basic

Public Property Millisecond As Integer

Syntax: C#

public int Millisecond {get; set;}

See Also

MySqlDateTime Class, MySql.Data.Types Namespace

Minute Property

Returns the minute portion of this datetime

Syntax: Visual Basic

Public Property Minute As Integer

Syntax: C#

public int Minute {get; set;}

See Also

MySqlDateTime Class, MySql.Data.Types Namespace

Month Property

Returns the month portion of this datetime

Syntax: Visual Basic

Public Property Month As Integer

Syntax: C#

public int Month {get; set;}

See Also

MySqlDateTime Class, MySql.Data.Types Namespace

Second Property

Returns the second portion of this datetime

Syntax: Visual Basic

Public Property Second As Integer

Syntax: C#

public int Second {get; set;}

See Also

MySqlDateTime Class, MySql.Data.Types Namespace

Year Property

Returns the year portion of this datetime

Syntax: Visual Basic

Public Property Year As Integer

Syntax: C#

public int Year {get; set;}

See Also

MySqlDateTime Class, MySql.Data.Types Namespace

MySqlDateTime.GetDateTime Method

Returns this value as a DateTime

Syntax: Visual Basic

Public Function GetDateTime() As Date

Syntax: C#

public DateTime GetDateTime();

See Also

MySqlDateTime Class, MySql.Data.Types Namespace

MySqlDateTime.ToString Method

Returns a MySQL-specific string representation of this value

Syntax: Visual Basic

Overrides Public Function ToString() As String

Syntax: C#

public override string ToString();

See Also

MySqlDateTime Class, MySql.Data.Types Namespace

Connector/Net Support

Connector/Net Community Support
How to Report Connector/Net Problems or Bugs
Connector/Net Change History

The developers of Connector/Net greatly value the input of our users in the software development process. If you find Connector/Net lacking some feature important to you, or if you discover a bug and need to file a bug report, please use the instructions in , "How to Report Bugs or Problems".

Connector/Net Community Support

How to Report Connector/Net Problems or Bugs

If you encounter difficulties or problems with Connector/Net, contact the Connector/Net community, as explained in , "Connector/Net Community Support".

First try to execute the same SQL statements and commands from the mysql client program or from admndemo. This helps you determine whether the error is in Connector/Net or MySQL.

If reporting a problem, ideally include the following information with the email:

Remember that the more information you can supply to us, the more likely it is that we can fix the problem.

If you believe the problem to be a bug, then you must report the bug through https://jira.mariadb.org/.

Connector/Net Change History

The Connector/Net Change History (Changelog) is located with the main Changelog for MySQL. See "MySQL Connector/Net Change History".

Connector/Net FAQ

Questions

Questions and Answers

21.2.9.1: How do I obtain the value of an auto-incremented column?

When using CommandBuilder, setting ReturnGeneratedIdentifiers property to true no longer works, as CommandBuilder does not add last_insert_id() by default.

CommandBuilder hooks up to the DataAdapter.RowUpdating event handler, which means it will get called for every row. It examines the command object and, if it is the same referenced object, it essentially rebuilds the object, thereby destroying your command text changes.

One approach to solving this problem is to clone the command object so you have a different actual reference: 

dataAdapter.InsertCommand = cb.GetInsertCommand().Clone()

This will work, but since the CommandBuilder is still connected to the DataAdapter, the RowUpdating event will still fire and performance will be hit. To stop that, once all your commands have been added you need to disconnect the CommandBuilder from the DataAdapter: 

cb.DataAdapter = null;

The last requirement is to make sure the id that is returned by last_insert_id() has the correct name. For example: 

SELECT last_insert_id() AS id

A complete working example is shown here: 

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Data;
using MySql.Data;
using MySql.Data.MySqlClient;
namespace GetAutoIncId
{
 class Program
 {
 static void Main(string[] args)
 {
 string connStr = 'server=localhost;user=root;database=TestDB;port=3306;password=******;';
 MySqlConnection conn = new MySqlConnection(connStr);
 try
 {
 Console.WriteLine('Connecting to MariaDB...');
 conn.Open();
 string sql = 'SELECT * FROM TestTable';
 MySqlDataAdapter da = new MySqlDataAdapter(sql, conn);
 MySqlCommandBuilder cb = new MySqlCommandBuilder(da);
 MySqlCommand cmd = new MySqlCommand();
 cmd.Connection = conn;
 cmd.CommandText = sql;
 // use Cloned object to avoid .NET rebuilding the object, and 
 // thereby throwing away our command text additions.
 MySqlCommand insertCmd = cb.GetInsertCommand().Clone(); 
 insertCmd.CommandText = insertCmd.CommandText + ';SELECT last_insert_id() AS id';
 insertCmd.UpdatedRowSource = UpdateRowSource.FirstReturnedRecord;
 da.InsertCommand = insertCmd;
 cb.DataAdapter = null; // Unhook RowUpdating event handler
 DataTable dt = new DataTable();
 da.Fill(dt);
 DataRow row = dt.NewRow();
 row['name'] = 'Joe Smith';
 dt.Rows.Add(row);
 da.Update(dt);
 System.Console.WriteLine('ID after update: ' + row['id']);
 }
 catch (Exception ex)
 {
 Console.WriteLine(ex.ToString());
 }
 conn.Close();
 Console.WriteLine('Done.');
 }
 }
}

MySQL Connector/J

Overview of MariaDB Connector/J
Connector/J Versions
Connector/J Installation
Connector/J Examples
Connector/J (JDBC) Reference
JDBC Concepts
J2EE Concepts
Using Connector/J with Tomcat
Using Connector/J with JBoss
Using Connector/J with Spring
Using Connector/J with GlassFish
Troubleshooting Connector/J
Connector/J Support

Overview of MariaDB Connector/J

MySQL provides connectivity for client applications developed in the Java programming language through a JDBC driver, which is called MariaDB Connector/J.

MySQL Connector/J is a JDBC Type 4 driver. Different versions are available that are compatible with the JDBC 3.0 and JDBC 4.0 specifications. The Type 4 designation means that the driver is pure-Java implementation of the MariaDB protocol and does not rely on the MariaDB client libraries.

For large-scale programs that use common design patterns of data access, consider using one of the popular persistence frameworks such as Hibernate, Spring's JDBC templates or Ibatis SQL Maps to reduce the amount of JDBC code for you to debug, tune, secure, and maintain.

This section is not designed to be a complete JDBC tutorial. If you need more information about using JDBC you might be interested in the following online tutorials that are more in-depth than the information presented here:

Key Topics

Connector/J Versions

Java Versions Supported

There are currently four versions of MariaDB Connector/J available:

The following table summarizes the Connector/J versions available:

Connector/J version Driver Type JDBC version MySQL Server version Status
5.1 4 3.0, 4.0 4.1, 5.0, 5.1, 5.4, 5.5 Recommended version
5.0 4 3.0 4.1, 5.0 Released version
3.1 4 3.0 4.1, 5.0 Obsolete
3.0 4 3.0 3.x, 4.1 Obsolete

The current recommended version for Connector/J is 5.1. This guide covers all four connector versions, with specific notes given where a setting applies to a specific option.

Java Versions Supported

The following table summarizes Connector/J Java dependencies:

Connector/J version Java RTE required JDK required (to build source code)
5.1 1.5.x, 1.6.x 1.6.x and 1.5.x
5.0 1.3.x, 1.4.x, 1.5.x, 1.6.x 1.4.2, 1.5.x, 1.6.x
3.1 1.2.x, 1.3.x, 1.4.x, 1.5.x, 1.6.x 1.4.2, 1.5.x, 1.6.x
3.0 1.2.x, 1.3.x, 1.4.x, 1.5.x, 1.6.x 1.4.2, 1.5.x, 1.6.x

MySQL Connector/J does not support JDK-1.1.x or JDK-1.0.x.

Because of the implementation of java.sql.Savepoint, Connector/J 3.1.0 and newer will not run on a Java runtime older than 1.4 unless the class verifier is turned off (by setting the -Xverify:none option to the Java runtime). This is because the class verifier will try to load the class definition for java.sql.Savepoint even though it is not accessed by the driver unless you actually use savepoint functionality.

Caching functionality provided by Connector/J 3.1.0 or newer is also not available on JVMs older than 1.4.x, as it relies on java.util.LinkedHashMap which was first available in JDK-1.4.0.

If you are building Connector/J from source code using the source distribution (see , "Installing from the Development Source Tree"), you must use JDK 1.4.2 or newer to compile the Connector package. For Connector/J 5.1, you must have both JDK-1.6.x and JDK-1.5.x installed to be able to build the source code.

Connector/J Installation

Installing Connector/J from a Binary Distribution
Installing the Driver and Configuring the CLASSPATH
Upgrading from an Older Version
Installing from the Development Source Tree

You can install the Connector/J package using either the binary or source distribution. The binary distribution provides the easiest method for installation; the source distribution lets you customize your installation further. With either solution, you manually add the Connector/J location to your Java CLASSPATH.

If you are upgrading from a previous version, read the upgrade information in , "Upgrading from an Older Version" before continuing.

Connector/J is also available as part of the Maven project. For more information, and to download the Connector/J JAR files, see the Maven repository.

Installing Connector/J from a Binary Distribution

For the easiest method of installation, use the binary distribution of the Connector/J package. The binary distribution is available either as a tar/gzip or zip file. Extract it to a suitable location, then optionally make the information about the package available by changing your CLASSPATH (see , "Installing the Driver and Configuring the CLASSPATH").

MySQL Connector/J is distributed as a .zip or .tar.gz archive containing the sources, the class files, and the JAR archive named mysql-connector-java-[version]-bin.jar.

Starting with Connector/J 3.1.9, the .class files that constitute the JAR files are only included as part of the driver JAR file.

Starting with Connector/J 3.1.8, the archive also includes a debug build of the driver in a file named mysql-connector-java-[version]-bin-g.jar. Do not use the debug build of the driver unless instructed to do so when reporting a problem or a bug, as it is not designed to be run in production environments, and will have adverse performance impact when used. The debug binary also depends on the Aspect/J runtime library, which is located in the src/lib/aspectjrt.jar file that comes with the Connector/J distribution.

Use the appropriate graphical or command-line utility to extract the distribution (for example, WinZip for the .zip archive, and tar for the .tar.gz archive). Because there are potentially long file names in the distribution, we use the GNU tar archive format. Use GNU tar (or an application that understands the GNU tar archive format) to unpack the .tar.gz variant of the distribution.

Installing the Driver and Configuring the CLASSPATH

Once you have extracted the distribution archive, you can install the driver by placing mysql-connector-java-[version]-bin.jar in your classpath, either by adding the full path to it to your CLASSPATH environment variable, or by directly specifying it with the command line switch -cp when starting the JVM.

To use the driver with the JDBC DriverManager, use com.mysql.jdbc.Driver as the class that implements java.sql.Driver.

You can set the CLASSPATH environment variable under UNIX, Linux or Mac OS X either locally for a user within their .profile, .login or other login file. You can also set it globally by editing the global /etc/profile file.

For example, add the Connector/J driver to your CLASSPATH using one of the following forms, depending on your command shell: 

# Bourne-compatible shell (sh, ksh, bash, zsh):
shell> export CLASSPATH=/path/mysql-connector-java-[ver]-bin.jar:$CLASSPATH
# C shell (csh, tcsh):
shell> setenv CLASSPATH /path/mysql-connector-java-[ver]-bin.jar:$CLASSPATH

Within Windows 2000, Windows XP, Windows Server 2003 and Windows Vista, you set the environment variable through the System Control Panel.

To use MariaDB Connector/J with an application server such as GlassFish, Tomcat or JBoss, read your vendor's documentation for more information on how to configure third-party class libraries, as most application servers ignore the CLASSPATH environment variable. For configuration examples for some J2EE application servers, see , "J2EE Concepts". However, the authoritative source for JDBC connection pool configuration information for your particular application server is the documentation for that application server.

If you are developing servlets or JSPs, and your application server is J2EE-compliant, you can put the driver's .jar file in the WEB-INF/lib subdirectory of your webapp, as this is a standard location for third party class libraries in J2EE web applications.

You can also use the MysqlDataSource or MysqlConnectionPoolDataSource classes in the com.mysql.jdbc.jdbc2.optional package, if your J2EE application server supports or requires them. Starting with Connector/J 5.0.0, the javax.sql.XADataSource interface is implemented using the com.mysql.jdbc.jdbc2.optional.MysqlXADataSource class, which supports XA distributed transactions when used in combination with MariaDB server version 5.0.

The various MysqlDataSource classes support the following parameters (through standard set mutators):

Upgrading from an Older Version

Upgrading from MariaDB Connector/J 3.0 to 3.1
Upgrading to MariaDB Connector/J 5.1.x
JDBC-Specific Issues When Upgrading to MariaDB Server 4.1 or Newer

This section has information for users who are upgrading from one version of Connector/J to another, or to a new version of the MariaDB server that supports a more recent level of JDBC. A newer version of Connector/J might include changes to support new features, improve existing functionality, or comply with new standards.

Upgrading from MariaDB Connector/J 3.0 to 3.1

Connector/J 3.1 is designed to be backward-compatible with Connector/J 3.0 as much as possible. Major changes are isolated to new functionality exposed in MySQL-4.1 and newer, which includes Unicode character sets, server-side prepared statements, SQLState codes returned in error messages by the server and various performance enhancements that can be enabled or disabled using configuration properties.

Upgrading to MariaDB Connector/J 5.1.x
JDBC-Specific Issues When Upgrading to MariaDB Server 4.1 or Newer

Installing from the Development Source Tree

Caution

Read this section only if you are interested in helping us test our new code. To just get MariaDB Connector/J up and running on your system, use a standard binary release distribution.

To install MariaDB Connector/J from the development source tree, make sure that you have the following prerequisites:

To check out and compile a specific branch of MariaDB Connector/J, follow these steps:

  1. Check out the latest code from the branch that you want with one of the following commands.

    The source code repository for MariaDB Connector/J is located on Launchpad at https://code.launchpad.net/connectorj. To check out the latest development branch, use: 

    shell> bzr branch lp:connectorji

    This creates a connectorj subdirectory in the current directory that contains the latest sources for the requested branch.

    To check out the latest 5.1 code, use: 

    shell> bzr branch lp:connectorj/5.1

    This creates a 5.1 subdirectory in the current directory containing the latest 5.1 code.

  2. To build Connector/J 5.1, make sure that you have both JDK 1.6.x installed and an older JDK such as JDK 1.5.x. This is because Connector/J supports both JDBC 3.0 (which was prior to JDK 1.6.x) and JDBC 4.0. Set your JAVA_HOME environment variable to the path of the older JDK installation.
  3. Change your current working directory to either the connectorj or 5.1 directory, depending on which branch you intend to build.
  4. To build Connector/J 5.1, edit the build.xml to reflect the location of your JDK 1.6.x installation. The lines to change are: 
     <property name="com.mysql.jdbc.java6.javac" value="C:\jvms\jdk1.6.0\bin\javac.exe" />
 <property name="com.mysql.jdbc.java6.rtjar" value="C:\jvms\jdk1.6.0\jre\lib\rt.jar" />

    Alternatively, you can set the value of these property names through the Ant -D option.

  5. Issue the following command to compile the driver and create a .jar file suitable for installation: 
    shell> ant dist

    This creates a build directory in the current directory, where all build output will go. A directory is created in the build directory that includes the version number of the sources you are building from. This directory contains the sources, compiled .class files, and a .jar file suitable for deployment. For other possible targets, including ones that will create a fully packaged distribution, issue the following command: 

    shell> ant -projecthelp
  6. A newly created .jar file containing the JDBC driver will be placed in the directory build/mysql-connector-java-[version].

    Install the newly created JDBC driver as you would a binary .jar file that you download from MySQL, by following the instructions in , "Installing the Driver and Configuring the CLASSPATH".

A package containing both the binary and source code for Connector/J 5.1 can also be found at the following location: Connector/J 5.1 Download

Connector/J Examples

Examples of using Connector/J are located throughout this document. This section provides a summary and links to these examples.

Connector/J (JDBC) Reference

Driver/Datasource Class Names, URL Syntax and Configuration Properties for Connector/J
JDBC API Implementation Notes
Java, JDBC and MariaDB Types
Using Character Sets and Unicode
Connecting Securely Using SSL
Using Master/Slave Replication with ReplicationConnection
Mapping MariaDB Error Numbers to SQLStates

This section of the manual contains reference material for MariaDB Connector/J, some of which is automatically generated during the Connector/J build process.

Driver/Datasource Class Names, URL Syntax and Configuration Properties for Connector/J

The name of the class that implements java.sql.Driver in MariaDB Connector/J is com.mysql.jdbc.Driver. The org.gjt.mm.mysql.Driver class name is also usable to remain backward-compatible with MM.MySQL. Use this class name when registering the driver, or when otherwise configuring software to use MariaDB Connector/J.

The JDBC URL format for MariaDB Connector/J is as follows, with items in square brackets ([, ]) being optional: 

jdbc:mysql://[host][,failoverhost...][:port]/[database] »
[?propertyName1][=propertyValue1][&propertyName2][=propertyValue2]...

If the host name is not specified, it defaults to 127.0.0.1. If the port is not specified, it defaults to 3306, the default port number for MariaDB servers. 

jdbc:mysql://[host:port],[host:port].../[database] »
[?propertyName1][=propertyValue1][&propertyName2][=propertyValue2]...

Here is a sample connection URL: 

jdbc:mysql://localhost:3306/sakila?profileSQL=true

If the database is not specified, the connection is made with no default database. In this case, either call the setCatalog() method on the Connection instance, or fully specify table names using the database name (that is, SELECT dbname.tablename.colname FROM dbname.tablename...) in your SQL. Not specifying the database to use upon connection is generally only useful when building tools that work with multiple databases, such as GUI database managers.Note

Always use the Connection.setCatalog() method to specify the desired database in JDBC applications, rather than the USE database statement.

MySQL Connector/J has fail-over support. This enables the driver to fail-over to any number of slave hosts and still perform read-only queries. Fail-over only happens when the connection is in an autoCommit(true) state, because fail-over can not happen reliably when a transaction is in progress. Most application servers and connection pools set autoCommit to true at the end of every transaction/connection use.

The fail-over functionality has the following behavior:

In either case, whenever you are connected to a 'failed-over' server, the connection will be set to read-only state, so queries that would modify data will have exceptions thrown (the query will never be processed by the MariaDB server).

Configuration properties define how Connector/J will make a connection to a MariaDB server. Unless otherwise noted, properties can be set for a DataSource object or for a Connection object.

Configuration properties can be set in one of the following ways:

The properties are listed in the following tables.

Connection/Authentication.

Property Name Definition Default Value Since Version
user The user to connect as all versions
password The password to use when connecting all versions
socketFactory The name of the class that the driver should use for creating socket connections to the server. This class must implement the interface 'com.mysql.jdbc.SocketFactory' and have public no-args constructor. com.mysql.jdbc.StandardSocketFactory 3.0.3
connectTimeout Timeout for socket connect (in milliseconds), with 0 being no timeout. Only works on JDK-1.4 or newer. Defaults to '0'. 0 3.0.1
socketTimeout Timeout on network socket operations (0, the default means no timeout). 0 3.0.1
connectionLifecycleInterceptors A comma-delimited list of classes that implement 'com.mysql.jdbc.ConnectionLifecycleInterceptor' that should notified of connection lifecycle events (creation, destruction, commit, rollback, setCatalog and setAutoCommit) and potentially alter the execution of these commands. ConnectionLifecycleInterceptors are 'stackable', more than one interceptor may be specified via the configuration property as a comma-delimited list, with the interceptors executed in order from left to right. 5.1.4
useConfigs Load the comma-delimited list of configuration properties before parsing the URL or applying user-specified properties. These configurations are explained in the 'Configurations' of the documentation. 3.1.5
authenticationPlugins Comma-delimited list of classes that implement com.mysql.jdbc.AuthenticationPlugin and which will be used for authentication unless disabled by 'disabledAuthenticationPlugins' property. 5.1.19
defaultAuthenticationPlugin Name of a class implementing com.mysql.jdbc.AuthenticationPlugin which will be used as the default authentication plugin (see below). It is an error to use a class which is not listed in 'authenticationPlugins' nor it is one of the built-in plugins. It is an error to set as default a plugin which was disabled with 'disabledAuthenticationPlugins' property. It is an error to set this value to null or the empty string (i.e. there must be at least a valid default authentication plugin specified for the connection, meeting all constraints listed above). com.mysql.jdbc.authentication.MysqlNativePasswordPlugin 5.1.19
disabledAuthenticationPlugins Comma-delimited list of classes implementing com.mysql.jdbc.AuthenticationPlugin or mechanisms, i.e. 'mysql_native_password'. The authentication plugins or mechanisms listed will not be used for authentication which will fail if it requires one of them. It is an error to disable the default authentication plugin (either the one named by 'defaultAuthenticationPlugin' property or the hard-coded one if 'defaultAuthenticationPlugin' propery is not set). 5.1.19
interactiveClient Set the CLIENT_INTERACTIVE flag, which tells MariaDB to timeout connections based on INTERACTIVE_TIMEOUT instead of WAIT_TIMEOUT false 3.1.0
localSocketAddress Hostname or IP address given to explicitly configure the interface that the driver will bind the client side of the TCP/IP connection to when connecting. 5.0.5
propertiesTransform An implementation of com.mysql.jdbc.ConnectionPropertiesTransform that the driver will use to modify URL properties passed to the driver before attempting a connection 3.1.4
useCompression Use zlib compression when communicating with the server (true/false)? Defaults to 'false'. false 3.0.17

Networking.

Property Name Definition Default Value Since Version
maxAllowedPacket Maximum allowed packet size to send to server. If not set, the value of system variable 'max_allowed_packet' will be used to initialize this upon connecting. This value will not take effect if set larger than the value of 'max_allowed_packet'. -1 5.1.8
tcpKeepAlive If connecting using TCP/IP, should the driver set SO_KEEPALIVE? true 5.0.7
tcpNoDelay If connecting using TCP/IP, should the driver set SO_TCP_NODELAY (disabling the Nagle Algorithm)? true 5.0.7
tcpRcvBuf If connecting using TCP/IP, should the driver set SO_RCV_BUF to the given value? The default value of '0', means use the platform default value for this property) 0 5.0.7
tcpSndBuf If connecting using TCP/IP, should the driver set SO_SND_BUF to the given value? The default value of '0', means use the platform default value for this property) 0 5.0.7
tcpTrafficClass If connecting using TCP/IP, should the driver set traffic class or type-of-service fields ?See the documentation for java.net.Socket.setTrafficClass() for more information. 0 5.0.7

High Availability and Clustering.

Property Name Definition Default Value Since Version
autoReconnect Should the driver try to re-establish stale and/or dead connections? If enabled the driver will throw an exception for a queries issued on a stale or dead connection, which belong to the current transaction, but will attempt reconnect before the next query issued on the connection in a new transaction. The use of this feature is not recommended, because it has side effects related to session state and data consistency when applications don't handle SQLExceptions properly, and is only designed to be used when you are unable to configure your application to handle SQLExceptions resulting from dead and stale connections properly. Alternatively, as a last option, investigate setting the MariaDB server variable 'wait_timeout' to a high value, rather than the default of 8 hours. false 1.1
autoReconnectForPools Use a reconnection strategy appropriate for connection pools (defaults to 'false') false 3.1.3
failOverReadOnly When failing over in autoReconnect mode, should the connection be set to 'read-only'? true 3.0.12
maxReconnects Maximum number of reconnects to attempt if autoReconnect is true, default is '3'. 3 1.1
reconnectAtTxEnd If autoReconnect is set to true, should the driver attempt reconnections at the end of every transaction? false 3.0.10
retriesAllDown When using loadbalancing, the number of times the driver should cycle through available hosts, attempting to connect. Between cycles, the driver will pause for 250ms if no servers are available. 120 5.1.6
initialTimeout If autoReconnect is enabled, the initial time to wait between re-connect attempts (in seconds, defaults to '2'). 2 1.1
roundRobinLoadBalance When autoReconnect is enabled, and failoverReadonly is false, should we pick hosts to connect to on a round-robin basis? false 3.1.2
queriesBeforeRetryMaster Number of queries to issue before falling back to master when failed over (when using multi-host failover). Whichever condition is met first, 'queriesBeforeRetryMaster' or 'secondsBeforeRetryMaster' will cause an attempt to be made to reconnect to the master. Defaults to 50. 50 3.0.2
secondsBeforeRetryMaster How long should the driver wait, when failed over, before attempting 30 3.0.2
selfDestructOnPingMaxOperations =If set to a non-zero value, the driver will report close the connection and report failure when Connection.ping() or Connection.isValid(int) is called if the connnection's count of commands sent to the server exceeds this value. 0 5.1.6
selfDestructOnPingSecondsLifetime If set to a non-zero value, the driver will report close the connection and report failure when Connection.ping() or Connection.isValid(int) is called if the connnection's lifetime exceeds this value. 0 5.1.6
resourceId A globally unique name that identifies the resource that this datasource or connection is connected to, used for XAResource.isSameRM() when the driver can't determine this value based on hostnames used in the URL 5.0.1

Security.

Property Name Definition Default Value Since Version
allowMultiQueries Allow the use of ';' to delimit multiple queries during one statement (true/false), defaults to 'false', and does not affect the addBatch() and executeBatch() methods, which instead rely on rewriteBatchStatements. false 3.1.1
useSSL Use SSL when communicating with the server (true/false), defaults to 'false' false 3.0.2
requireSSL Require SSL connection if useSSL=true? (defaults to 'false'). false 3.1.0
verifyServerCertificate If 'useSSL' is set to 'true', should the driver verify the server's certificate? When using this feature, the keystore parameters should be specified by the 'clientCertificateKeyStore*' properties, rather than system properties. true 5.1.6
clientCertificateKeyStoreUrl URL to the client certificate KeyStore (if not specified, use defaults) 5.1.0
clientCertificateKeyStoreType KeyStore type for client certificates (NULL or empty means use the default, which is 'JKS'. Standard keystore types supported by the JVM are 'JKS' and 'PKCS12', your environment may have more available depending on what security products are installed and available to the JVM. JKS 5.1.0
clientCertificateKeyStorePassword Password for the client certificates KeyStore 5.1.0
trustCertificateKeyStoreUrl URL to the trusted root certificate KeyStore (if not specified, use defaults) 5.1.0
trustCertificateKeyStoreType KeyStore type for trusted root certificates (NULL or empty means use the default, which is 'JKS'. Standard keystore types supported by the JVM are 'JKS' and 'PKCS12', your environment may have more available depending on what security products are installed and available to the JVM. JKS 5.1.0
trustCertificateKeyStorePassword Password for the trusted root certificates KeyStore 5.1.0
allowLoadLocalInfile Should the driver allow use of 'LOAD DATA LOCAL INFILE...' (defaults to 'true'). true 3.0.3
allowUrlInLocalInfile Should the driver allow URLs in 'LOAD DATA LOCAL INFILE' statements? false 3.1.4
paranoid Take measures to prevent exposure sensitive information in error messages and clear data structures holding sensitive data when possible? (defaults to 'false') false 3.0.1
passwordCharacterEncoding What character encoding is used for passwords? Leaving this set to the default value (null), uses the platform character set, which works for ISO8859_1 (i.e. 'latin1') passwords. For passwords in other character encodings, the encoding will have to be specified with this property, as it's not possible for the driver to auto-detect this. 5.1.7

Performance Extensions.

Property Name Definition Default Value Since Version
callableStmtCacheSize If 'cacheCallableStmts' is enabled, how many callable statements should be cached? 100 3.1.2
metadataCacheSize The number of queries to cache ResultSetMetadata for if cacheResultSetMetaData is set to 'true' (default 50) 50 3.1.1
useLocalSessionState Should the driver refer to the internal values of autocommit and transaction isolation that are set by Connection.setAutoCommit() and Connection.setTransactionIsolation() and transaction state as maintained by the protocol, rather than querying the database or blindly sending commands to the database for commit() or rollback() method calls? false 3.1.7
useLocalTransactionState Should the driver use the in-transaction state provided by the MariaDB protocol to determine if a commit() or rollback() should actually be sent to the database? false 5.1.7
prepStmtCacheSize If prepared statement caching is enabled, how many prepared statements should be cached? 25 3.0.10
prepStmtCacheSqlLimit If prepared statement caching is enabled, what's the largest SQL the driver will cache the parsing for? 256 3.0.10
alwaysSendSetIsolation Should the driver always communicate with the database when Connection.setTransactionIsolation() is called? If set to false, the driver will only communicate with the database when the requested transaction isolation is different than the whichever is newer, the last value that was set via Connection.setTransactionIsolation(), or the value that was read from the server when the connection was established. Note that useLocalSessionState=true will force the same behavior as alwaysSendSetIsolation=false, regardless of how alwaysSendSetIsolation is set. true 3.1.7
maintainTimeStats Should the driver maintain various internal timers to enable idle time calculations as well as more verbose error messages when the connection to the server fails? Setting this property to false removes at least two calls to System.getCurrentTimeMillis() per query. true 3.1.9
useCursorFetch If connected to MariaDB > 5.0.2, and setFetchSize() > 0 on a statement, should that statement use cursor-based fetching to retrieve rows? false 5.0.0
blobSendChunkSize Chunk to use when sending BLOB/CLOBs via ServerPreparedStatements 1048576 3.1.9
cacheCallableStmts Should the driver cache the parsing stage of CallableStatements false 3.1.2
cachePrepStmts Should the driver cache the parsing stage of PreparedStatements of client-side prepared statements, the 'check' for suitability of server-side prepared and server-side prepared statements themselves? false 3.0.10
cacheResultSetMetadata Should the driver cache ResultSetMetaData for Statements and PreparedStatements? (Req. JDK-1.4+, true/false, default 'false') false 3.1.1
cacheServerConfiguration Should the driver cache the results of 'SHOW VARIABLES' and 'SHOW COLLATION' on a per-URL basis? false 3.1.5
defaultFetchSize The driver will call setFetchSize(n) with this value on all newly-created Statements 0 3.1.9
dontTrackOpenResources The JDBC specification requires the driver to automatically track and close resources, however if your application doesn't do a good job of explicitly calling close() on statements or result sets, this can cause memory leakage. Setting this property to true relaxes this constraint, and can be more memory efficient for some applications. false 3.1.7
dynamicCalendars Should the driver retrieve the default calendar when required, or cache it per connection/session? false 3.1.5
elideSetAutoCommits If using MySQL-4.1 or newer, should the driver only issue 'set autocommit=n' queries when the server's state doesn't match the requested state by Connection.setAutoCommit(boolean)? false 3.1.3
enableQueryTimeouts When enabled, query timeouts set via Statement.setQueryTimeout() use a shared java.util.Timer instance for scheduling. Even if the timeout doesn't expire before the query is processed, there will be memory used by the TimerTask for the given timeout which won't be reclaimed until the time the timeout would have expired if it hadn't been cancelled by the driver. High-load environments might want to consider disabling this functionality. true 5.0.6
holdResultsOpenOverStatementClose Should the driver close result sets on Statement.close() as required by the JDBC specification? false 3.1.7
largeRowSizeThreshold What size result set row should the JDBC driver consider 'large', and thus use a more memory-efficient way of representing the row internally? 2048 5.1.1
loadBalanceStrategy If using a load-balanced connection to connect to SQL nodes in a MariaDB Cluster/NDB configuration (by using the URL prefix 'jdbc:mysql:loadbalance://'), which load balancing algorithm should the driver use: (1) 'random' - the driver will pick a random host for each request. This tends to work better than round-robin, as the randomness will somewhat account for spreading loads where requests vary in response time, while round-robin can sometimes lead to overloaded nodes if there are variations in response times across the workload. (2) 'bestResponseTime' - the driver will route the request to the host that had the best response time for the previous transaction. random 5.0.6
locatorFetchBufferSize If 'emulateLocators' is configured to 'true', what size buffer should be used when fetching BLOB data for getBinaryInputStream? 1048576 3.2.1
rewriteBatchedStatements Should the driver use multiqueries (irregardless of the setting of 'allowMultiQueries') as well as rewriting of prepared statements for INSERT into multi-value inserts when executeBatch() is called? Notice that this has the potential for SQL injection if using plain java.sql.Statements and your code doesn't sanitize input correctly. Notice that for prepared statements, server-side prepared statements can not currently take advantage of this rewrite option, and that if you don't specify stream lengths when using PreparedStatement.set*Stream(), the driver won't be able to determine the optimum number of parameters per batch and you might receive an error from the driver that the resultant packet is too large. Statement.getGeneratedKeys() for these rewritten statements only works when the entire batch includes INSERT statements. false 3.1.13
useDirectRowUnpack Use newer result set row unpacking code that skips a copy from network buffers to a MariaDB packet instance and instead reads directly into the result set row data buffers. true 5.1.1
useDynamicCharsetInfo Should the driver use a per-connection cache of character set information queried from the server when necessary, or use a built-in static mapping that is more efficient, but isn't aware of custom character sets or character sets implemented after the release of the JDBC driver? true 5.0.6
useFastDateParsing Use internal String->Date/Time/Timestamp conversion routines to avoid excessive object creation? true 5.0.5
useFastIntParsing Use internal String->Integer conversion routines to avoid excessive object creation? true 3.1.4
useJvmCharsetConverters Always use the character encoding routines built into the JVM, rather than using lookup tables for single-byte character sets? false 5.0.1
useReadAheadInput Use newer, optimized non-blocking, buffered input stream when reading from the server? true 3.1.5

Debugging/Profiling.

Property Name Definition Default Value Since Version
logger The name of a class that implements 'com.mysql.jdbc.log.Log' that will be used to log messages to. (default is 'com.mysql.jdbc.log.StandardLogger', which logs to STDERR) com.mysql.jdbc.log.StandardLogger 3.1.1
gatherPerfMetrics Should the driver gather performance metrics, and report them via the configured logger every 'reportMetricsIntervalMillis' milliseconds? false 3.1.2
profileSQL Trace queries and their execution/fetch times to the configured logger (true/false) defaults to 'false' false 3.1.0
profileSql Deprecated, use 'profileSQL' instead. Trace queries and their execution/fetch times on STDERR (true/false) defaults to 'false' 2.0.14
reportMetricsIntervalMillis If 'gatherPerfMetrics' is enabled, how often should they be logged (in ms)? 30000 3.1.2
maxQuerySizeToLog Controls the maximum length/size of a query that will get logged when profiling or tracing 2048 3.1.3
packetDebugBufferSize The maximum number of packets to retain when 'enablePacketDebug' is true 20 3.1.3
slowQueryThresholdMillis If 'logSlowQueries' is enabled, how long should a query (in ms) before it is logged as 'slow'? 2000 3.1.2
slowQueryThresholdNanos If 'useNanosForElapsedTime' is set to true, and this property is set to a non-zero value, the driver will use this threshold (in nanosecond units) to determine if a query was slow. 0 5.0.7
useUsageAdvisor Should the driver issue 'usage' warnings advising proper and efficient usage of JDBC and MariaDB Connector/J to the log (true/false, defaults to 'false')? false 3.1.1
autoGenerateTestcaseScript Should the driver dump the SQL it is executing, including server-side prepared statements to STDERR? false 3.1.9
autoSlowLog Instead of using slowQueryThreshold* to determine if a query is slow enough to be logged, maintain statistics that allow the driver to determine queries that are outside the 99th percentile? true 5.1.4
clientInfoProvider The name of a class that implements the com.mysql.jdbc.JDBC4ClientInfoProvider interface in order to support JDBC-4.0's Connection.get/setClientInfo() methods com.mysql.jdbc.JDBC4CommentClientInfoProvider 5.1.0
dumpMetadataOnColumnNotFound Should the driver dump the field-level metadata of a result set into the exception message when ResultSet.findColumn() fails? false 3.1.13
dumpQueriesOnException Should the driver dump the contents of the query sent to the server in the message for SQLExceptions? false 3.1.3
enablePacketDebug When enabled, a ring-buffer of 'packetDebugBufferSize' packets will be kept, and dumped when exceptions are thrown in key areas in the driver's code false 3.1.3
explainSlowQueries If 'logSlowQueries' is enabled, should the driver automatically issue an 'EXPLAIN' on the server and send the results to the configured log at a WARN level? false 3.1.2
includeInnodbStatusInDeadlockExceptions Include the output of 'SHOW ENGINE INNODB STATUS' in exception messages when deadlock exceptions are detected? false 5.0.7
includeThreadDumpInDeadlockExceptions Include a current Java thread dump in exception messages when deadlock exceptions are detected? false 5.1.15
includeThreadNamesAsStatementComment Include the name of the current thread as a comment visible in 'SHOW PROCESSLIST', or in Innodb deadlock dumps, useful in correlation with 'includeInnodbStatusInDeadlockExceptions=true' and 'includeThreadDumpInDeadlockExceptions=true'. false 5.1.15
logSlowQueries Should queries that take longer than 'slowQueryThresholdMillis' be logged? false 3.1.2
logXaCommands Should the driver log XA commands sent by MysqlXaConnection to the server, at the DEBUG level of logging? false 5.0.5
profilerEventHandler Name of a class that implements the interface com.mysql.jdbc.profiler.ProfilerEventHandler that will be used to handle profiling/tracing events. com.mysql.jdbc.profiler.LoggingProfilerEventHandler 5.1.6
resultSetSizeThreshold If the usage advisor is enabled, how many rows should a result set contain before the driver warns that it is suspiciously large? 100 5.0.5
traceProtocol Should trace-level network protocol be logged? false 3.1.2
useNanosForElapsedTime For profiling/debugging functionality that measures elapsed time, should the driver try to use nanoseconds resolution if available (JDK >= 1.5)? false 5.0.7

Miscellaneous.

Property Name Definition Default Value Since Version
useUnicode Should the driver use Unicode character encodings when handling strings? Should only be used when the driver can't determine the character set mapping, or you are trying to 'force' the driver to use a character set that MariaDB either doesn't natively support (such as UTF-8), true/false, defaults to 'true' true 1.1g
characterEncoding If 'useUnicode' is set to true, what character encoding should the driver use when dealing with strings? (defaults is to 'autodetect') 1.1g
characterSetResults Character set to tell the server to return results as. 3.0.13
connectionCollation If set, tells the server to use this collation via 'set collation_connection' 3.0.13
useBlobToStoreUTF8OutsideBMP Tells the driver to treat [MEDIUM/LONG]BLOB columns as [LONG]VARCHAR columns holding text encoded in UTF-8 that has characters outside the BMP (4-byte encodings), which MariaDB server can't handle natively. false 5.1.3
utf8OutsideBmpExcludedColumnNamePattern When 'useBlobToStoreUTF8OutsideBMP' is set to 'true', column names matching the given regex will still be treated as BLOBs unless they match the regex specified for 'utf8OutsideBmpIncludedColumnNamePattern'. The regex must follow the patterns used for the java.util.regex package. 5.1.3
utf8OutsideBmpIncludedColumnNamePattern Used to specify exclusion rules to 'utf8OutsideBmpExcludedColumnNamePattern'. The regex must follow the patterns used for the java.util.regex package. 5.1.3
loadBalanceEnableJMX Enables JMX-based management of load-balanced connection groups, including live addition/removal of hosts from load-balancing pool. false 5.1.13
sessionVariables A comma-separated list of name/value pairs to be sent as SET SESSION ... to the server when the driver connects. 3.1.8
useColumnNamesInFindColumn Prior to JDBC-4.0, the JDBC specification had a bug related to what could be given as a 'column name' to ResultSet methods like findColumn(), or getters that took a String property. JDBC-4.0 clarified 'column name' to mean the label, as given in an 'AS' clause and returned by ResultSetMetaData.getColumnLabel(), and if no AS clause, the column name. Setting this property to 'true' will give behavior that is congruent to JDBC-3.0 and earlier versions of the JDBC specification, but which because of the specification bug could give unexpected results. This property is preferred over 'useOldAliasMetadataBehavior' unless you need the specific behavior that it provides with respect to ResultSetMetadata. false 5.1.7
allowNanAndInf Should the driver allow NaN or +/- INF values in PreparedStatement.setDouble()? false 3.1.5
autoClosePStmtStreams Should the driver automatically call .close() on streams/readers passed as arguments via set*() methods? false 3.1.12
autoDeserialize Should the driver automatically detect and de-serialize objects stored in BLOB fields? false 3.1.5
blobsAreStrings Should the driver always treat BLOBs as Strings - specifically to work around dubious metadata returned by the server for GROUP BY clauses? false 5.0.8
capitalizeTypeNames Capitalize type names in DatabaseMetaData? (usually only useful when using WebObjects, true/false, defaults to 'false') true 2.0.7
clobCharacterEncoding The character encoding to use for sending and retrieving TEXT, MEDIUMTEXT and LONGTEXT values instead of the configured connection characterEncoding 5.0.0
clobberStreamingResults This will cause a 'streaming' ResultSet to be automatically closed, and any outstanding data still streaming from the server to be discarded if another query is executed before all the data has been read from the server. false 3.0.9
compensateOnDuplicateKeyUpdateCounts Should the driver compensate for the update counts of 'ON DUPLICATE KEY' INSERT statements (2 = 1, 0 = 1) when using prepared statements? false 5.1.7
continueBatchOnError Should the driver continue processing batch commands if one statement fails. The JDBC spec allows either way (defaults to 'true'). true 3.0.3
createDatabaseIfNotExist Creates the database given in the URL if it doesn't yet exist. Assumes the configured user has permissions to create databases. false 3.1.9
emptyStringsConvertToZero Should the driver allow conversions from empty string fields to numeric values of '0'? true 3.1.8
emulateLocators Should the driver emulate java.sql.Blobs with locators? With this feature enabled, the driver will delay loading the actual Blob data until the one of the retrieval methods (getInputStream(), getBytes(), and so forth) on the blob data stream has been accessed. For this to work, you must use a column alias with the value of the column to the actual name of the Blob. The feature also has the following restrictions: The SELECT that created the result set must reference only one table, the table must have a primary key; the SELECT must alias the original blob column name, specified as a string, to an alternate name; the SELECT must cover all columns that make up the primary key. false 3.1.0
emulateUnsupportedPstmts Should the driver detect prepared statements that are not supported by the server, and replace them with client-side emulated versions? true 3.1.7
exceptionInterceptors Comma-delimited list of classes that implement com.mysql.jdbc.ExceptionInterceptor. These classes will be instantiated one per Connection instance, and all SQLExceptions thrown by the driver will be allowed to be intercepted by these interceptors, in a chained fashion, with the first class listed as the head of the chain. 5.1.8
functionsNeverReturnBlobs Should the driver always treat data from functions returning BLOBs as Strings - specifically to work around dubious metadata returned by the server for GROUP BY clauses? false 5.0.8
generateSimpleParameterMetadata Should the driver generate simplified parameter metadata for PreparedStatements when no metadata is available either because the server couldn't support preparing the statement, or server-side prepared statements are disabled? false 5.0.5
ignoreNonTxTables Ignore non-transactional table warning for rollback? (defaults to 'false'). false 3.0.9
jdbcCompliantTruncation Should the driver throw java.sql.DataTruncation exceptions when data is truncated as is required by the JDBC specification when connected to a server that supports warnings (MySQL 4.1.0 and newer)? This property has no effect if the server sql-mode includes STRICT_TRANS_TABLES. true 3.1.2
loadBalanceAutoCommitStatementRegex When load-balancing is enabled for auto-commit statements (via loadBalanceAutoCommitStatementThreshold), the statement counter will only increment when the SQL matches the regular expression. By default, every statement issued matches. 5.1.15
loadBalanceAutoCommitStatementThreshold When auto-commit is enabled, the number of statements which should be executed before triggering load-balancing to rebalance. Default value of 0 causes load-balanced connections to only rebalance when exceptions are encountered, or auto-commit is disabled and transactions are explicitly committed or rolled back. 0 5.1.15
loadBalanceBlacklistTimeout Time in milliseconds between checks of servers which are unavailable, by controlling how long a server lives in the global blacklist. 0 5.1.0
loadBalanceConnectionGroup Logical group of load-balanced connections within a classloader, used to manage different groups independently. If not specified, live management of load-balanced connections is disabled. 5.1.13
loadBalanceExceptionChecker Fully-qualified class name of custom exception checker. The class must implement com.mysql.jdbc.LoadBalanceExceptionChecker interface, and is used to inspect SQLExceptions and determine whether they should trigger fail-over to another host in a load-balanced deployment. com.mysql.jdbc.StandardLoadBalanceExceptionChecker 5.1.13
loadBalancePingTimeout Time in milliseconds to wait for ping response from each of load-balanced physical connections when using load-balanced Connection. 0 5.1.13
loadBalanceSQLExceptionSubclassFailover Comma-delimited list of classes/interfaces used by default load-balanced exception checker to determine whether a given SQLException should trigger failover. The comparison is done using Class.isInstance(SQLException) using the thrown SQLException. 5.1.13
loadBalanceSQLStateFailover Comma-delimited list of SQLState codes used by default load-balanced exception checker to determine whether a given SQLException should trigger failover. The SQLState of a given SQLException is evaluated to determine whether it begins with any value in the comma-delimited list. 5.1.13
loadBalanceValidateConnectionOnSwapServer Should the load-balanced Connection explicitly check whether the connection is live when swapping to a new physical connection at commit/rollback? false 5.1.13
maxRows The maximum number of rows to return (0, the default means return all rows). -1 all versions
netTimeoutForStreamingResults What value should the driver automatically set the server setting 'net_write_timeout' to when the streaming result sets feature is in use? (value has unit of seconds, the value '0' means the driver will not try and adjust this value) 600 5.1.0
noAccessToProcedureBodies When determining procedure parameter types for CallableStatements, and the connected user can't access procedure bodies through 'SHOW CREATE PROCEDURE' or select on mysql.proc should the driver instead create basic metadata (all parameters reported as IN VARCHARs, but allowing registerOutParameter() to be called on them anyway) instead of throwing an exception? false 5.0.3
noDatetimeStringSync Don't ensure that ResultSet.getDatetimeType().toString().equals(ResultSet.getString()) false 3.1.7
noTimezoneConversionForTimeType Don't convert TIME values using the server timezone if 'useTimezone'='true' false 5.0.0
nullCatalogMeansCurrent When DatabaseMetadataMethods ask for a 'catalog' parameter, does the value null mean use the current catalog? (this is not JDBC-compliant, but follows legacy behavior from earlier versions of the driver) true 3.1.8
nullNamePatternMatchesAll Should DatabaseMetaData methods that accept *pattern parameters treat null the same as '%' (this is not JDBC-compliant, however older versions of the driver accepted this departure from the specification) true 3.1.8
overrideSupportsIntegrityEnhancementFacility Should the driver return 'true' for DatabaseMetaData.supportsIntegrityEnhancementFacility() even if the database doesn't support it to workaround applications that require this method to return 'true' to signal support of foreign keys, even though the SQL specification states that this facility contains much more than just foreign key support (one such application being OpenOffice)? false 3.1.12
padCharsWithSpace If a result set column has the CHAR type and the value does not fill the amount of characters specified in the DDL for the column, should the driver pad the remaining characters with space (for ANSI compliance)? false 5.0.6
pedantic Follow the JDBC spec to the letter. false 3.0.0
pinGlobalTxToPhysicalConnection When using XAConnections, should the driver ensure that operations on a given XID are always routed to the same physical connection? This allows the XAConnection to support 'XA START ... JOIN' after 'XA END' has been called false 5.0.1
populateInsertRowWithDefaultValues When using ResultSets that are CONCUR_UPDATABLE, should the driver pre-populate the 'insert' row with default values from the DDL for the table used in the query so those values are immediately available for ResultSet accessors? This functionality requires a call to the database for metadata each time a result set of this type is created. If disabled (the default), the default values will be populated by the an internal call to refreshRow() which pulls back default values and/or values changed by triggers. false 5.0.5
processEscapeCodesForPrepStmts Should the driver process escape codes in queries that are prepared? true 3.1.12
queryTimeoutKillsConnection If the timeout given in Statement.setQueryTimeout() expires, should the driver forcibly abort the Connection instead of attempting to abort the query? false 5.1.9
relaxAutoCommit If the version of MariaDB the driver connects to does not support transactions, still allow calls to commit(), rollback() and setAutoCommit() (true/false, defaults to 'false')? false 2.0.13
retainStatementAfterResultSetClose Should the driver retain the Statement reference in a ResultSet after ResultSet.close() has been called. This is not JDBC-compliant after JDBC-4.0. false 3.1.11
rollbackOnPooledClose Should the driver issue a rollback() when the logical connection in a pool is closed? true 3.0.15
runningCTS13 Enables workarounds for bugs in Sun's JDBC compliance testsuite version 1.3 false 3.1.7
serverTimezone Override detection/mapping of timezone. Used when timezone from server doesn't map to Java timezone 3.0.2
statementInterceptors A comma-delimited list of classes that implement 'com.mysql.jdbc.StatementInterceptor' that should be placed 'in between' query execution to influence the results. StatementInterceptors are 'chainable', the results returned by the 'current' interceptor will be passed on to the next in in the chain, from left-to-right order, as specified in this property. 5.1.1
strictFloatingPoint Used only in older versions of compliance test false 3.0.0
strictUpdates Should the driver do strict checking (all primary keys selected) of updatable result sets (true, false, defaults to 'true')? true 3.0.4
tinyInt1isBit Should the driver treat the datatype TINYINT(1) as the BIT type (because the server silently converts BIT -> TINYINT(1) when creating tables)? true 3.0.16
transformedBitIsBoolean If the driver converts TINYINT(1) to a different type, should it use BOOLEAN instead of BIT for future compatibility with MySQL-5.0, as MySQL-5.0 has a BIT type? false 3.1.9
treatUtilDateAsTimestamp Should the driver treat java.util.Date as a TIMESTAMP for the purposes of PreparedStatement.setObject()? true 5.0.5
ultraDevHack Create PreparedStatements for prepareCall() when required, because UltraDev is broken and issues a prepareCall() for _all_ statements? (true/false, defaults to 'false') false 2.0.3
useAffectedRows Don't set the CLIENT_FOUND_ROWS flag when connecting to the server (not JDBC-compliant, will break most applications that rely on 'found' rows vs. 'affected rows' for DML statements), but does cause 'correct' update counts from 'INSERT ... ON DUPLICATE KEY UPDATE' statements to be returned by the server. false 5.1.7
useGmtMillisForDatetimes Convert between session timezone and GMT before creating Date and Timestamp instances (value of 'false' is legacy behavior, 'true' leads to more JDBC-compliant behavior. false 3.1.12
useHostsInPrivileges Add '@hostname' to users in DatabaseMetaData.getColumn/TablePrivileges() (true/false), defaults to 'true'. true 3.0.2
useInformationSchema When connected to MySQL-5.0.7 or newer, should the driver use the INFORMATION_SCHEMA to derive information used by DatabaseMetaData? false 5.0.0
useJDBCCompliantTimezoneShift Should the driver use JDBC-compliant rules when converting TIME/TIMESTAMP/DATETIME values' timezone information for those JDBC arguments which take a java.util.Calendar argument? (Notice that this option is exclusive of the 'useTimezone=true' configuration option.) false 5.0.0
useLegacyDatetimeCode Use code for DATE/TIME/DATETIME/TIMESTAMP handling in result sets and statements that consistently handles timezone conversions from client to server and back again, or use the legacy code for these datatypes that has been in the driver for backwards-compatibility? true 5.1.6
useOldAliasMetadataBehavior Should the driver use the legacy behavior for 'AS' clauses on columns and tables, and only return aliases (if any) for ResultSetMetaData.getColumnName() or ResultSetMetaData.getTableName() rather than the original column/table name? In 5.0.x, the default value was true. false 5.0.4
useOldUTF8Behavior Use the UTF-8 behavior the driver did when communicating with 4.0 and older servers false 3.1.6
useOnlyServerErrorMessages Don't prepend 'standard' SQLState error messages to error messages returned by the server. true 3.0.15
useSSPSCompatibleTimezoneShift If migrating from an environment that was using server-side prepared statements, and the configuration property 'useJDBCCompliantTimeZoneShift' set to 'true', use compatible behavior when not using server-side prepared statements when sending TIMESTAMP values to the MariaDB server. false 5.0.5
useServerPrepStmts Use server-side prepared statements if the server supports them? false 3.1.0
useSqlStateCodes Use SQL Standard state codes instead of 'legacy' X/Open/SQL state codes (true/false), default is 'true' true 3.1.3
useStreamLengthsInPrepStmts Honor stream length parameter in PreparedStatement/ResultSet.setXXXStream() method calls (true/false, defaults to 'true')? true 3.0.2
useTimezone Convert time/date types between client and server timezones (true/false, defaults to 'false')? false 3.0.2
useUnbufferedInput Don't use BufferedInputStream for reading data from the server true 3.0.11
yearIsDateType Should the JDBC driver treat the MariaDB type 'YEAR' as a java.sql.Date, or as a SHORT? true 3.1.9
zeroDateTimeBehavior What should happen when the driver encounters DATETIME values that are composed entirely of zeros (used by MariaDB to represent invalid dates)? Valid values are 'exception', 'round' and 'convertToNull'. exception 3.1.4

Connector/J also supports access to MariaDB using named pipes on Windows NT/2000/XP using the NamedPipeSocketFactory as a plugin-socket factory using the socketFactory property. If you do not use a namedPipePath property, the default of '\\.\pipe\MySQL' is used. If you use the NamedPipeSocketFactory, the host name and port number values in the JDBC url are ignored. To enable this feature, use: 

socketFactory=com.mysql.jdbc.NamedPipeSocketFactory

Named pipes only work when connecting to a MariaDB server on the same physical machine as the one the JDBC driver is being used on. In simple performance tests, it appears that named pipe access is between 30%-50% faster than the standard TCP/IP access. However, this varies per system, and named pipes are slower than TCP/IP in many Windows configurations.

To create your own socket factories, follow the example code in com.mysql.jdbc.NamedPipeSocketFactory, or com.mysql.jdbc.StandardSocketFactory.

JDBC API Implementation Notes

MySQL Connector/J passes all of the tests in the publicly available version of Sun's JDBC compliance test suite. this section gives details on a interface-by-interface level about implementation decisions that might affect how you code applications with MariaDB Connector/J. The JDBC specification is vague about how certain functionality should be implemented, or the specification enables leeway in implementation.

Java, JDBC and MariaDB Types

MySQL Connector/J is flexible in the way it handles conversions between MariaDB data types and Java data types.

In general, any MariaDB data type can be converted to a java.lang.String, and any numeric type can be converted to any of the Java numeric types, although round-off, overflow, or loss of precision may occur.Note

All TEXT types return Types.LONGVARCHAR with different getPrecision() values (65535, 255, 16777215, and 2147483647 respectively) with getColumnType() returning -1. This behavior is intentional even though TINYTEXT does not fall, regarding to its size, within the LONGVARCHAR category. This is to avoid different handling inside the same base type. And getColumnType() returns -1 because the internal server handling is of type TEXT, which is similar to BLOB.

Also note that getColumnTypeName() will return VARCHAR even though getColumnType() returns Types.LONGVARCHAR, because VARCHAR is the designated column database-specific name for this type.

Starting with Connector/J 3.1.0, the JDBC driver issues warnings or throws DataTruncation exceptions as is required by the JDBC specification unless the connection was configured not to do so by using the property jdbcCompliantTruncation and setting it to false.

The conversions that are always guaranteed to work are listed in the following table:

Connection Properties - Miscellaneous.

These MariaDB Data Types Can always be converted to these Java types
CHAR, VARCHAR, BLOB, TEXT, ENUM, and SET java.lang.String, java.io.InputStream, java.io.Reader, java.sql.Blob, java.sql.Clob
FLOAT, REAL, DOUBLE PRECISION, NUMERIC, DECIMAL, TINYINT, SMALLINT, MEDIUMINT, INTEGER, BIGINT java.lang.String, java.lang.Short, java.lang.Integer, java.lang.Long, java.lang.Double, java.math.BigDecimal
DATE, TIME, DATETIME, TIMESTAMP java.lang.String, java.sql.Date, java.sql.Timestamp
Note

Round-off, overflow or loss of precision may occur if you choose a Java numeric data type that has less precision or capacity than the MariaDB data type you are converting to/from.

The ResultSet.getObject() method uses the type conversions between MariaDB and Java types, following the JDBC specification where appropriate. The value returned by ResultSetMetaData.GetColumnClassName() is also shown below. For more information on the java.sql.Types classes see Java 2 Platform Types.

MySQL Types to Java Types for ResultSet.getObject().

MySQL Type Name Return value of GetColumnClassName Returned as Java Class
BIT(1) (new in MySQL-5.0) BIT java.lang.Boolean
BIT( > 1) (new in MySQL-5.0) BIT byte[]
TINYINT TINYINT java.lang.Boolean if the configuration property tinyInt1isBit is set to true (the default) and the storage size is 1, or java.lang.Integer if not.
BOOL, BOOLEAN TINYINT See TINYINT, above as these are aliases for TINYINT(1), currently.
SMALLINT[(M)] [UNSIGNED] SMALLINT [UNSIGNED] java.lang.Integer (regardless if UNSIGNED or not)
MEDIUMINT[(M)] [UNSIGNED] MEDIUMINT [UNSIGNED] java.lang.Integer, if UNSIGNED java.lang.Long (C/J 3.1 and earlier), or java.lang.Integer for C/J 5.0 and later
INT,INTEGER[(M)] [UNSIGNED] INTEGER [UNSIGNED] java.lang.Integer, if UNSIGNED java.lang.Long
BIGINT[(M)] [UNSIGNED] BIGINT [UNSIGNED] java.lang.Long, if UNSIGNED java.math.BigInteger
FLOAT[(M,D)] FLOAT java.lang.Float
DOUBLE[(M,B)] DOUBLE java.lang.Double
DECIMAL[(M[,D])] DECIMAL java.math.BigDecimal
DATE DATE java.sql.Date
DATETIME DATETIME java.sql.Timestamp
TIMESTAMP[(M)] TIMESTAMP java.sql.Timestamp
TIME TIME java.sql.Time
YEAR[(2|4)] YEAR If yearIsDateType configuration property is set to false, then the returned object type is java.sql.Short. If set to true (the default), then the returned object is of type java.sql.Date with the date set to January 1st, at midnight.
CHAR(M) CHAR java.lang.String (unless the character set for the column is BINARY, then byte[] is returned.
VARCHAR(M) [BINARY] VARCHAR java.lang.String (unless the character set for the column is BINARY, then byte[] is returned.
BINARY(M) BINARY byte[]
VARBINARY(M) VARBINARY byte[]
TINYBLOB TINYBLOB byte[]
TINYTEXT VARCHAR java.lang.String
BLOB BLOB byte[]
TEXT VARCHAR java.lang.String
MEDIUMBLOB MEDIUMBLOB byte[]
MEDIUMTEXT VARCHAR java.lang.String
LONGBLOB LONGBLOB byte[]
LONGTEXT VARCHAR java.lang.String
ENUM('value1','value2',...) CHAR java.lang.String
SET('value1','value2',...) CHAR java.lang.String

Using Character Sets and Unicode

All strings sent from the JDBC driver to the server are converted automatically from native Java Unicode form to the client character encoding, including all queries sent using Statement.execute(), Statement.executeUpdate(), Statement.executeQuery() as well as all PreparedStatement and CallableStatement parameters with the exclusion of parameters set using setBytes(), setBinaryStream(), setAsciiStream(), setUnicodeStream() and setBlob().

Prior to MariaDB Server 4.1, Connector/J supported a single character encoding per connection, which could either be automatically detected from the server configuration, or could be configured by the user through the useUnicode and characterEncoding properties.

Starting with MariaDB Server 4.1, Connector/J supports a single character encoding between client and server, and any number of character encodings for data returned by the server to the client in ResultSets.

The character encoding between client and server is automatically detected upon connection. The encoding used by the driver is specified on the server using the character_set system variable for server versions older than 4.1.0 and character-set-server for server versions 4.1.0 and newer. For more information, see , "Server Character Set and Collation".

To override the automatically detected encoding on the client side, use the characterEncoding property in the URL used to connect to the server.

When specifying character encodings on the client side, use Java-style names. The following table lists Java-style names for MariaDB character sets:

MySQL to Java Encoding Name Translations.

MySQL Character Set Name Java-Style Character Encoding Name
ascii US-ASCII
big5 Big5
gbk GBK
sjis SJIS (or Cp932 or MS932 for MariaDB Server < 4.1.11)
cp932 Cp932 or MS932 (MySQL Server > 4.1.11)
gb2312 EUC_CN
ujis EUC_JP
euckr EUC_KR
latin1 Cp1252
latin2 ISO8859_2
greek ISO8859_7
hebrew ISO8859_8
cp866 Cp866
tis620 TIS620
cp1250 Cp1250
cp1251 Cp1251
cp1257 Cp1257
macroman MacRoman
macce MacCentralEurope
utf8 UTF-8
ucs2 UnicodeBig
Warning

Do not issue the query 'set names' with Connector/J, as the driver will not detect that the character set has changed, and will continue to use the character set detected during the initial connection setup.

To allow multiple character sets to be sent from the client, use the UTF-8 encoding, either by configuring utf8 as the default server character set, or by configuring the JDBC driver to use UTF-8 through the characterEncoding property.

Connecting Securely Using SSL

SSL in MariaDB Connector/J encrypts all data (other than the initial handshake) between the JDBC driver and the server. The performance penalty for enabling SSL is an increase in query processing time between 35% and 50%, depending on the size of the query, and the amount of data it returns.

For SSL Support to work, you must have the following:

The system works through two Java truststore files, one file contains the certificate information for the server (truststore in the examples below). The other file contains the certificate for the client (keystore in the examples below). All Java truststore files are password protected by supplying a suitable password to the keytool when you create the files. You need the file names and associated passwords to create an SSL connection.

You will first need to import the MariaDB server CA Certificate into a Java truststore. A sample MariaDB server CA Certificate is located in the SSL subdirectory of the MariaDB source distribution. This is what SSL will use to determine if you are communicating with a secure MariaDB server. Alternatively, use the CA Certificate that you have generated or been provided with by your SSL provider.

To use Java's keytool to create a truststore in the current directory , and import the server's CA certificate (cacert.pem), you can do the following (assuming that keytool is in your path. The keytool is typically located in the bin subdirectory of your JDK or JRE): 

shell> keytool -import -alias mysqlServerCACert \
 -file cacert.pem -keystore truststore

Enter the password when prompted for the keystore file. Interaction with keytool looks like this: 

Enter keystore password: *********
Owner: EMAILADDRESS=walrus@example.com, CN=Walrus,
 O=MariaDB Foundation, L=Orenburg, ST=Some-State, C=RU Issuer: EMAILADDRESS=walrus@example.com, CN=Walrus,
 O=MariaDB Foundation, L=Orenburg, ST=Some-State, C=RU Serial number: 0
Valid from:
 Fri Aug 02 16:55:53 CDT 2002 until: Sat Aug 02 16:55:53 CDT 2003
Certificate fingerprints:
 MD5: 61:91:A0:F2:03:07:61:7A:81:38:66:DA:19:C4:8D:AB
 SHA1: 25:77:41:05:D5:AD:99:8C:14:8C:CA:68:9C:2F:B8:89:C3:34:4D:6C Trust this certificate? [no]: yes Certificate was added to keystore

You then have two options: either import the client certificate that matches the CA certificate you just imported, or create a new client certificate.

Importing an existing certificate requires the certificate to be in DER format. You can use openssl to convert an existing certificate into the new format. For example: 

shell> openssl x509 -outform DER -in client-cert.pem -out client.cert

Now import the converted certificate into your keystore using keytool: 

shell> keytool -import -file client.cert -keystore keystore -alias mysqlClientCertificate

To generate your own client certificate, use keytool to create a suitable certificate and add it to the keystore file: 

shell> keytool -genkey -keyalg rsa \
 -alias mysqlClientCertificate -keystore keystore

Keytool will prompt you for the following information, and create a keystore named keystore in the current directory.

Respond with information that is appropriate for your situation: 

Enter keystore password: *********
What is your first and last name?
 [Unknown]: Matthews What is the name of your organizational unit?
 [Unknown]: Software Development What is the name of your organization?
 [Unknown]: MariaDB Foundation What is the name of your City or Locality?
 [Unknown]: Flossmoor What is the name of your State or Province?
 [Unknown]: IL What is the two-letter country code for this unit?
 [Unknown]: US Is <CN=Matthews, OU=Software Development, O=MariaDB Foundation,
 L=Flossmoor, ST=IL, C=US> correct?
 [no]: y Enter key password for <mysqlClientCertificate>
 (RETURN if same as keystore password):

Finally, to get JSSE to use the keystore and truststore that you have generated, you need to set the following system properties when you start your JVM, replacing path_to_keystore_file with the full path to the keystore file you created, path_to_truststore_file with the path to the truststore file you created, and using the appropriate password values for each property. You can do this either on the command line: 

-Djavax.net.ssl.keyStore=path_to_keystore_file
-Djavax.net.ssl.keyStorePassword=password
-Djavax.net.ssl.trustStore=path_to_truststore_file
-Djavax.net.ssl.trustStorePassword=password

Or you can set the values directly within the application: 

System.setProperty('javax.net.ssl.keyStore','path_to_keystore_file');
System.setProperty('javax.net.ssl.keyStorePassword','password');
System.setProperty('javax.net.ssl.trustStore','path_to_truststore_file');
System.setProperty('javax.net.ssl.trustStorePassword','password');

You will also need to set useSSL to true in your connection parameters for MariaDB Connector/J, either by adding useSSL=true to your URL, or by setting the property useSSL to true in the java.util.Properties instance you pass to DriverManager.getConnection().

You can test that SSL is working by turning on JSSE debugging (as detailed below), and look for the following key events: 

...
*** ClientHello, v3.1
RandomCookie: GMT: 1018531834 bytes = { 199, 148, 180, 215, 74, 12, »
 54, 244, 0, 168, 55, 103, 215, 64, 16, 138, 225, 190, 132, 153, 2, »
 217, 219, 239, 202, 19, 121, 78 }
Session ID: {}
Cipher Suites: { 0, 5, 0, 4, 0, 9, 0, 10, 0, 18, 0, 19, 0, 3, 0, 17 }
Compression Methods: { 0 }
***
[write] MD5 and SHA1 hashes: len = 59
0000: 01 00 00 37 03 01 3D B6 90 FA C7 94 B4 D7 4A 0C ...7..=.......J.
0010: 36 F4 00 A8 37 67 D7 40 10 8A E1 BE 84 99 02 D9 6...7g.@........
0020: DB EF CA 13 79 4E 00 00 10 00 05 00 04 00 09 00 ....yN..........
0030: 0A 00 12 00 13 00 03 00 11 01 00 ...........
main, WRITE: SSL v3.1 Handshake, length = 59
main, READ: SSL v3.1 Handshake, length = 74
*** ServerHello, v3.1
RandomCookie: GMT: 1018577560 bytes = { 116, 50, 4, 103, 25, 100, 58, »
 202, 79, 185, 178, 100, 215, 66, 254, 21, 83, 187, 190, 42, 170, 3, »
 132, 110, 82, 148, 160, 92 }
Session ID: {163, 227, 84, 53, 81, 127, 252, 254, 178, 179, 68, 63, »
 182, 158, 30, 11, 150, 79, 170, 76, 255, 92, 15, 226, 24, 17, 177, »
 219, 158, 177, 187, 143}
Cipher Suite: { 0, 5 }
Compression Method: 0
***
%% Created: [Session-1, SSL_RSA_WITH_RC4_128_SHA]
** SSL_RSA_WITH_RC4_128_SHA
[read] MD5 and SHA1 hashes: len = 74
0000: 02 00 00 46 03 01 3D B6 43 98 74 32 04 67 19 64 ...F..=.C.t2.g.d
0010: 3A CA 4F B9 B2 64 D7 42 FE 15 53 BB BE 2A AA 03 :.O..d.B..S..*..
0020: 84 6E 52 94 A0 5C 20 A3 E3 54 35 51 7F FC FE B2 .nR..\ ..T5Q....
0030: B3 44 3F B6 9E 1E 0B 96 4F AA 4C FF 5C 0F E2 18 .D?.....O.L.\...
0040: 11 B1 DB 9E B1 BB 8F 00 05 00 ..........
main, READ: SSL v3.1 Handshake, length = 1712
...

JSSE provides debugging (to STDOUT) when you set the following system property: -Djavax.net.debug=all This will tell you what keystores and truststores are being used, as well as what is going on during the SSL handshake and certificate exchange. It will be helpful when trying to determine what is not working when trying to get an SSL connection to happen.

Using Master/Slave Replication with ReplicationConnection

Starting with Connector/J 3.1.7, we've made available a variant of the driver that will automatically send queries to a read/write master, or a failover or round-robin loadbalanced set of slaves based on the state of Connection.getReadOnly() .

An application signals that it wants a transaction to be read-only by calling Connection.setReadOnly(true), this replication-aware connection will use one of the slave connections, which are load-balanced per-vm using a round-robin scheme (a given connection is sticky to a slave unless that slave is removed from service). If you have a write transaction, or if you have a read that is time-sensitive (remember, replication in MariaDB is asynchronous), set the connection to be not read-only, by calling Connection.setReadOnly(false) and the driver will ensure that further calls are sent to the master MariaDB server. The driver takes care of propagating the current state of autocommit, isolation level, and catalog between all of the connections that it uses to accomplish this load balancing functionality.

To enable this functionality, use the ' com.mysql.jdbc.ReplicationDriver ' class when configuring your application server's connection pool or when creating an instance of a JDBC driver for your standalone application. Because it accepts the same URL format as the standard MariaDB JDBC driver, ReplicationDriver does not currently work with java.sql.DriverManager -based connection creation unless it is the only MariaDB JDBC driver registered with the DriverManager .

Here is a short, simple example of how ReplicationDriver might be used in a standalone application. 

import java.sql.Connection;
import java.sql.ResultSet;
import java.util.Properties;
import com.mysql.jdbc.ReplicationDriver;
public class ReplicationDriverDemo {
 public static void main(String[] args) throws Exception {
 ReplicationDriver driver = new ReplicationDriver();
 Properties props = new Properties();
 // We want this for failover on the slaves
 props.put('autoReconnect', 'true');
 // We want to load balance between the slaves
 props.put('roundRobinLoadBalance', 'true');
 props.put('user', 'foo');
 props.put('password', 'bar');
 //
 // Looks like a normal MariaDB JDBC url, with a
 // comma-separated list of hosts, the first
 // being the 'master', the rest being any number
 // of slaves that the driver will load balance against
 //
 Connection conn =
 driver.connect('jdbc:mysql:replication://master,slave1,slave2,slave3/test',
 props);
 //
 // Perform read/write work on the master
 // by setting the read-only flag to 'false'
 //
 conn.setReadOnly(false);
 conn.setAutoCommit(false);
 conn.createStatement().executeUpdate('UPDATE some_table ....');
 conn.commit();
 //
 // Now, do a query from a slave, the driver automatically picks one
 // from the list
 //
 conn.setReadOnly(true);
 ResultSet rs =
 conn.createStatement().executeQuery('SELECT a,b FROM alt_table');
 .......
 }
}

Consider investigating the Load Balancing JDBC Pool (lbpol) tool, which provides a wrapper around the standard JDBC driver and enables you to use DB connection pools that includes checks for system failures and uneven load distribution. For more information, see Load Balancing JDBC Pool (lbpool).

Mapping MariaDB Error Numbers to SQLStates

The table below provides a mapping of the MariaDB Error Numbers to SQL States

Table 20.6. Mapping of MariaDB Error Numbers to SQLStates

MySQL Error Number MySQL Error Name Legacy (X/Open) SQLState SQL Standard SQLState
1022 ER_DUP_KEY S1000 23000
1037 ER_OUTOFMEMORY S1001 HY001
1038 ER_OUT_OF_SORTMEMORY S1001 HY001
1040 ER_CON_COUNT_ERROR 08004 08004
1042 ER_BAD_HOST_ERROR 08004 08S01
1043 ER_HANDSHAKE_ERROR 08004 08S01
1044 ER_DBACCESS_DENIED_ERROR S1000 42000
1045 ER_ACCESS_DENIED_ERROR 28000 28000
1047 ER_UNKNOWN_COM_ERROR 08S01 HY000
1050 ER_TABLE_EXISTS_ERROR S1000 42S01
1051 ER_BAD_TABLE_ERROR 42S02 42S02
1052 ER_NON_UNIQ_ERROR S1000 23000
1053 ER_SERVER_SHUTDOWN S1000 08S01
1054 ER_BAD_FIELD_ERROR S0022 42S22
1055 ER_WRONG_FIELD_WITH_GROUP S1009 42000
1056 ER_WRONG_GROUP_FIELD S1009 42000
1057 ER_WRONG_SUM_SELECT S1009 42000
1058 ER_WRONG_VALUE_COUNT 21S01 21S01
1059 ER_TOO_LONG_IDENT S1009 42000
1060 ER_DUP_FIELDNAME S1009 42S21
1061 ER_DUP_KEYNAME S1009 42000
1062 ER_DUP_ENTRY S1009 23000
1063 ER_WRONG_FIELD_SPEC S1009 42000
1064 ER_PARSE_ERROR 42000 42000
1065 ER_EMPTY_QUERY 42000 42000
1066 ER_NONUNIQ_TABLE S1009 42000
1067 ER_INVALID_DEFAULT S1009 42000
1068 ER_MULTIPLE_PRI_KEY S1009 42000
1069 ER_TOO_MANY_KEYS S1009 42000
1070 ER_TOO_MANY_KEY_PARTS S1009 42000
1071 ER_TOO_LONG_KEY S1009 42000
1072 ER_KEY_COLUMN_DOES_NOT_EXITS S1009 42000
1073 ER_BLOB_USED_AS_KEY S1009 42000
1074 ER_TOO_BIG_FIELDLENGTH S1009 42000
1075 ER_WRONG_AUTO_KEY S1009 42000
1080 ER_FORCING_CLOSE S1000 08S01
1081 ER_IPSOCK_ERROR 08S01 08S01
1082 ER_NO_SUCH_INDEX S1009 42S12
1083 ER_WRONG_FIELD_TERMINATORS S1009 42000
1084 ER_BLOBS_AND_NO_TERMINATED S1009 42000
1090 ER_CANT_REMOVE_ALL_FIELDS S1000 42000
1091 ER_CANT_DROP_FIELD_OR_KEY S1000 42000
1101 ER_BLOB_CANT_HAVE_DEFAULT S1000 42000
1102 ER_WRONG_DB_NAME S1000 42000
1103 ER_WRONG_TABLE_NAME S1000 42000
1104 ER_TOO_BIG_SELECT S1000 42000
1106 ER_UNKNOWN_PROCEDURE S1000 42000
1107 ER_WRONG_PARAMCOUNT_TO_PROCEDURE S1000 42000
1109 ER_UNKNOWN_TABLE S1000 42S02
1110 ER_FIELD_SPECIFIED_TWICE S1000 42000
1112 ER_UNSUPPORTED_EXTENSION S1000 42000
1113 ER_TABLE_MUST_HAVE_COLUMNS S1000 42000
1115 ER_UNKNOWN_CHARACTER_SET S1000 42000
1118 ER_TOO_BIG_ROWSIZE S1000 42000
1120 ER_WRONG_OUTER_JOIN S1000 42000
1121 ER_NULL_COLUMN_IN_INDEX S1000 42000
1129 ER_HOST_IS_BLOCKED 08004 HY000
1130 ER_HOST_NOT_PRIVILEGED 08004 HY000
1131 ER_PASSWORD_ANONYMOUS_USER S1000 42000
1132 ER_PASSWORD_NOT_ALLOWED S1000 42000
1133 ER_PASSWORD_NO_MATCH S1000 42000
1136 ER_WRONG_VALUE_COUNT_ON_ROW S1000 21S01
1138 ER_INVALID_USE_OF_NULL S1000 42000
1139 ER_REGEXP_ERROR S1000 42000
1140 ER_MIX_OF_GROUP_FUNC_AND_FIELDS S1000 42000
1141 ER_NONEXISTING_GRANT S1000 42000
1142 ER_TABLEACCESS_DENIED_ERROR S1000 42000
1143 ER_COLUMNACCESS_DENIED_ERROR S1000 42000
1144 ER_ILLEGAL_GRANT_FOR_TABLE S1000 42000
1145 ER_GRANT_WRONG_HOST_OR_USER S1000 42000
1146 ER_NO_SUCH_TABLE S1000 42S02
1147 ER_NONEXISTING_TABLE_GRANT S1000 42000
1148 ER_NOT_ALLOWED_COMMAND S1000 42000
1149 ER_SYNTAX_ERROR S1000 42000
1152 ER_ABORTING_CONNECTION S1000 08S01
1153 ER_NET_PACKET_TOO_LARGE S1000 08S01
1154 ER_NET_READ_ERROR_FROM_PIPE S1000 08S01
1155 ER_NET_FCNTL_ERROR S1000 08S01
1156 ER_NET_PACKETS_OUT_OF_ORDER S1000 08S01
1157 ER_NET_UNCOMPRESS_ERROR S1000 08S01
1158 ER_NET_READ_ERROR S1000 08S01
1159 ER_NET_READ_INTERRUPTED S1000 08S01
1160 ER_NET_ERROR_ON_WRITE S1000 08S01
1161 ER_NET_WRITE_INTERRUPTED S1000 08S01
1162 ER_TOO_LONG_STRING S1000 42000
1163 ER_TABLE_CANT_HANDLE_BLOB S1000 42000
1164 ER_TABLE_CANT_HANDLE_AUTO_INCREMENT S1000 42000
1166 ER_WRONG_COLUMN_NAME S1000 42000
1167 ER_WRONG_KEY_COLUMN S1000 42000
1169 ER_DUP_UNIQUE S1000 23000
1170 ER_BLOB_KEY_WITHOUT_LENGTH S1000 42000
1171 ER_PRIMARY_CANT_HAVE_NULL S1000 42000
1172 ER_TOO_MANY_ROWS S1000 42000
1173 ER_REQUIRES_PRIMARY_KEY S1000 42000
1177 ER_CHECK_NO_SUCH_TABLE S1000 42000
1178 ER_CHECK_NOT_IMPLEMENTED S1000 42000
1179 ER_CANT_DO_THIS_DURING_AN_TRANSACTION S1000 25000
1184 ER_NEW_ABORTING_CONNECTION S1000 08S01
1189 ER_MASTER_NET_READ S1000 08S01
1190 ER_MASTER_NET_WRITE S1000 08S01
1203 ER_TOO_MANY_USER_CONNECTIONS S1000 42000
1205 ER_LOCK_WAIT_TIMEOUT 41000 41000
1207 ER_READ_ONLY_TRANSACTION S1000 25000
1211 ER_NO_PERMISSION_TO_CREATE_USER S1000 42000
1213 ER_LOCK_DEADLOCK 41000 40001
1216 ER_NO_REFERENCED_ROW S1000 23000
1217 ER_ROW_IS_REFERENCED S1000 23000
1218 ER_CONNECT_TO_MASTER S1000 08S01
1222 ER_WRONG_NUMBER_OF_COLUMNS_IN_SELECT S1000 21000
1226 ER_USER_LIMIT_REACHED S1000 42000
1230 ER_NO_DEFAULT S1000 42000
1231 ER_WRONG_VALUE_FOR_VAR S1000 42000
1232 ER_WRONG_TYPE_FOR_VAR S1000 42000
1234 ER_CANT_USE_OPTION_HERE S1000 42000
1235 ER_NOT_SUPPORTED_YET S1000 42000
1239 ER_WRONG_FK_DEF S1000 42000
1241 ER_OPERAND_COLUMNS S1000 21000
1242 ER_SUBQUERY_NO_1_ROW S1000 21000
1247 ER_ILLEGAL_REFERENCE S1000 42S22
1248 ER_DERIVED_MUST_HAVE_ALIAS S1000 42000
1249 ER_SELECT_REDUCED S1000 01000
1250 ER_TABLENAME_NOT_ALLOWED_HERE S1000 42000
1251 ER_NOT_SUPPORTED_AUTH_MODE S1000 08004
1252 ER_SPATIAL_CANT_HAVE_NULL S1000 42000
1253 ER_COLLATION_CHARSET_MISMATCH S1000 42000
1261 ER_WARN_TOO_FEW_RECORDS S1000 01000
1262 ER_WARN_TOO_MANY_RECORDS S1000 01000
1263 ER_WARN_NULL_TO_NOTNULL S1000 01000
1264 ER_WARN_DATA_OUT_OF_RANGE S1000 01000
1265 ER_WARN_DATA_TRUNCATED S1000 01000
1280 ER_WRONG_NAME_FOR_INDEX S1000 42000
1281 ER_WRONG_NAME_FOR_CATALOG S1000 42000
1286 ER_UNKNOWN_STORAGE_ENGINE S1000 42000

JDBC Concepts

Connecting to MariaDB Using the DriverManager Interface
Using Statements to Execute SQL
Using CallableStatements to Execute Stored Procedures
Retrieving AUTO_INCREMENT Column Values

This section provides some general JDBC background.

Connecting to MariaDB Using the DriverManager Interface

When you are using JDBC outside of an application server, the DriverManager class manages the establishment of Connections.

Specify to the DriverManager which JDBC drivers to try to make Connections with. The easiest way to do this is to use Class.forName() on the class that implements the java.sql.Driver interface. With MariaDB Connector/J, the name of this class is com.mysql.jdbc.Driver. With this method, you could use an external configuration file to supply the driver class name and driver parameters to use when connecting to a database.

The following section of Java code shows how you might register MariaDB Connector/J from the main() method of your application. If testing this code, first read the installation section at , "Connector/J Installation", to make sure you have connector installed correctly and the CLASSPATH set up. Also, ensure that MariaDB is configured to accept external TCP/IP connections. 

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
// Notice, do not import com.mysql.jdbc.*
// or you will have problems!
public class LoadDriver {
 public static void main(String[] args) {
 try {
 // The newInstance() call is a work around for some
 // broken Java implementations
 Class.forName('com.mysql.jdbc.Driver').newInstance();
 } catch (Exception ex) {
 // handle the error
 }
 }
}

After the driver has been registered with the DriverManager, you can obtain a Connection instance that is connected to a particular database by calling DriverManager.getConnection():

Example 20.1. Connector/J: Obtaining a connection from the DriverManager

If you have not already done so, please review the section , "Connecting to MariaDB Using the DriverManager Interface" before working with these examples.

This example shows how you can obtain a Connection instance from the DriverManager. There are a few different signatures for the getConnection() method. Consult the API documentation that comes with your JDK for more specific information on how to use them. 

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
Connection conn = null;
...
try {
 conn =
 DriverManager.getConnection('jdbc:mysql://localhost/test?' +
 'user=monty&password=greatsqldb');
 // Do something with the Connection
 ...
} catch (SQLException ex) {
 // handle any errors
 System.out.println('SQLException: ' + ex.getMessage());
 System.out.println('SQLState: ' + ex.getSQLState());
 System.out.println('VendorError: ' + ex.getErrorCode());
}

Once a Connection is established, it can be used to create Statement and PreparedStatement objects, as well as retrieve metadata about the database. This is explained in the following sections.

Using Statements to Execute SQL

Statement objects allow you to execute basic SQL queries and retrieve the results through the ResultSet class which is described later.

To create a Statement instance, you call the createStatement() method on the Connection object you have retrieved using one of the DriverManager.getConnection() or DataSource.getConnection() methods described earlier.

Once you have a Statement instance, you can execute a SELECT query by calling the executeQuery(String) method with the SQL you want to use.

To update data in the database, use the executeUpdate(String SQL) method. This method returns the number of rows matched by the update statement, not the number of rows that were modified.

If you do not know ahead of time whether the SQL statement will be a SELECT or an UPDATE/INSERT, then you can use the execute(String SQL) method. This method will return true if the SQL query was a SELECT, or false if it was an UPDATE, INSERT, or DELETE statement. If the statement was a SELECT query, you can retrieve the results by calling the getResultSet() method. If the statement was an UPDATE, INSERT, or DELETE statement, you can retrieve the affected rows count by calling getUpdateCount() on the Statement instance.

Example 20.2. Connector/J: Using java.sql.Statement to execute a SELECT query 

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.sql.Statement;
import java.sql.ResultSet;
// assume that conn is an already created JDBC connection (see previous examples)
Statement stmt = null;
ResultSet rs = null;
try {
 stmt = conn.createStatement();
 rs = stmt.executeQuery('SELECT foo FROM bar');
 // or alternatively, if you don't know ahead of time that
 // the query will be a SELECT...
 if (stmt.execute('SELECT foo FROM bar')) {
 rs = stmt.getResultSet();
 }
 // Now do something with the ResultSet ....
}
catch (SQLException ex){
 // handle any errors
 System.out.println('SQLException: ' + ex.getMessage());
 System.out.println('SQLState: ' + ex.getSQLState());
 System.out.println('VendorError: ' + ex.getErrorCode());
}
finally {
 // it is a good idea to release
 // resources in a finally{} block
 // in reverse-order of their creation
 // if they are no-longer needed
 if (rs != null) {
 try {
 rs.close();
 } catch (SQLException sqlEx) { } // ignore
 rs = null;
 }
 if (stmt != null) {
 try {
 stmt.close();
 } catch (SQLException sqlEx) { } // ignore
 stmt = null;
 }
}

Using CallableStatements to Execute Stored Procedures

Starting with MariaDB server version 5.0 when used with Connector/J 3.1.1 or newer, the java.sql.CallableStatement interface is fully implemented with the exception of the getParameterMetaData() method.

For more information on MariaDB stored procedures, please refer to http://dev.mysql.com/doc/mysql/en/stored-routines.html.

Connector/J exposes stored procedure functionality through JDBC's CallableStatement interface.Note

Current versions of MariaDB server do not return enough information for the JDBC driver to provide result set metadata for callable statements. This means that when using CallableStatement, ResultSetMetaData may return NULL.

The following example shows a stored procedure that returns the value of inOutParam incremented by 1, and the string passed in using inputParam as a ResultSet:

Example 20.3. Connector/J: Calling Stored Procedures

CREATE PROCEDURE demoSp(IN inputParam VARCHAR(255), \
 INOUT inOutParam INT)
BEGIN
 DECLARE z INT;
 SET z = inOutParam + 1;
 SET inOutParam = z;
 SELECT inputParam;
 SELECT CONCAT('zyxw', inputParam);
END

To use the demoSp procedure with Connector/J, follow these steps:

  1. Prepare the callable statement by using Connection.prepareCall().

    Notice that you have to use JDBC escape syntax, and that the parentheses surrounding the parameter placeholders are not optional:

    Example 20.4. Connector/J: Using Connection.prepareCall() 

    import java.sql.CallableStatement;
...
 //
 // Prepare a call to the stored procedure 'demoSp'
 // with two parameters
 //
 // Notice the use of JDBC-escape syntax ({call ...})
 //
 CallableStatement cStmt = conn.prepareCall('{call demoSp(?, ?)}');
 cStmt.setString(1, 'abcdefg');
    Note

    Connection.prepareCall() is an expensive method, due to the metadata retrieval that the driver performs to support output parameters. For performance reasons, minimize unnecessary calls to Connection.prepareCall() by reusing CallableStatement instances in your code.

  2. Register the output parameters (if any exist)

    To retrieve the values of output parameters (parameters specified as OUT or INOUT when you created the stored procedure), JDBC requires that they be specified before statement execution using the various registerOutputParameter() methods in the CallableStatement interface:

    Example 20.5. Connector/J: Registering output parameters

    import java.sql.Types;
...
//
// Connector/J supports both named and indexed
// output parameters. You can register output
// parameters using either method, as well
// as retrieve output parameters using either
// method, regardless of what method was
// used to register them.
//
// The following examples show how to use
// the various methods of registering
// output parameters (you should of course
// use only one registration per parameter).
//
//
// Registers the second parameter as output, and
// uses the type 'INTEGER' for values returned from
// getObject()
//
cStmt.registerOutParameter(2, Types.INTEGER);
//
// Registers the named parameter 'inOutParam', and
// uses the type 'INTEGER' for values returned from
// getObject()
//
cStmt.registerOutParameter('inOutParam', Types.INTEGER);
...
  3. Set the input parameters (if any exist)

    Input and in/out parameters are set as for PreparedStatement objects. However, CallableStatement also supports setting parameters by name:

    Example 20.6. Connector/J: Setting CallableStatement input parameters 

    ...
 //
 // Set a parameter by index
 //
 cStmt.setString(1, 'abcdefg');
 //
 // Alternatively, set a parameter using
 // the parameter name
 //
 cStmt.setString('inputParameter', 'abcdefg');
 //
 // Set the 'in/out' parameter using an index
 //
 cStmt.setInt(2, 1);
 //
 // Alternatively, set the 'in/out' parameter
 // by name
 //
 cStmt.setInt('inOutParam', 1);
...
  4. Execute the CallableStatement, and retrieve any result sets or output parameters.

    Although CallableStatement supports calling any of the Statement execute methods (executeUpdate(), executeQuery() or execute()), the most flexible method to call is execute(), as you do not need to know ahead of time if the stored procedure returns result sets:

    Example 20.7. Connector/J: Retrieving results and output parameter values

    ...
 boolean hadResults = cStmt.execute();
 //
 // Process all returned result sets
 //
 while (hadResults) {
 ResultSet rs = cStmt.getResultSet();
 // process result set
 ...
 hadResults = cStmt.getMoreResults();
 }
 //
 // Retrieve output parameters
 //
 // Connector/J supports both index-based and
 // name-based retrieval
 //
 int outputValue = cStmt.getInt(2); // index-based
 outputValue = cStmt.getInt('inOutParam'); // name-based
...

Retrieving AUTO_INCREMENT Column Values

Before version 3.0 of the JDBC API, there was no standard way of retrieving key values from databases that supported auto increment or identity columns. With older JDBC drivers for MySQL, you could always use a MySQL-specific method on the Statement interface, or issue the query SELECT LAST_INSERT_ID() after issuing an INSERT to a table that had an AUTO_INCREMENT key. Using the MySQL-specific method call isn't portable, and issuing a SELECT to get the AUTO_INCREMENT key's value requires another round-trip to the database, which isn't as efficient as possible. The following code snippets demonstrate the three different ways to retrieve AUTO_INCREMENT values. First, we demonstrate the use of the new JDBC-3.0 method getGeneratedKeys() which is now the preferred method to use if you need to retrieve AUTO_INCREMENT keys and have access to JDBC-3.0. The second example shows how you can retrieve the same value using a standard SELECT LAST_INSERT_ID() query. The final example shows how updatable result sets can retrieve the AUTO_INCREMENT value when using the insertRow() method.

Example 20.8. Connector/J: Retrieving AUTO_INCREMENT column values using Statement.getGeneratedKeys() 

 Statement stmt = null;
 ResultSet rs = null;
 try {
 //
 // Create a Statement instance that we can use for
 // 'normal' result sets assuming you have a
 // Connection 'conn' to a MariaDB database already
 // available
 stmt = conn.createStatement(java.sql.ResultSet.TYPE_FORWARD_ONLY,
 java.sql.ResultSet.CONCUR_UPDATABLE);
 //
 // Issue the DDL queries for the table for this example
 //
 stmt.executeUpdate('DROP TABLE IF EXISTS autoIncTutorial');
 stmt.executeUpdate(
 'CREATE TABLE autoIncTutorial ('
 + 'priKey INT NOT NULL AUTO_INCREMENT, '
 + 'dataField VARCHAR(64), PRIMARY KEY (priKey))');
 //
 // Insert one row that will generate an AUTO INCREMENT
 // key in the 'priKey' field
 //
 stmt.executeUpdate(
 'INSERT INTO autoIncTutorial (dataField) '
 + 'values ('Can I Get the Auto Increment Field?')',
 Statement.RETURN_GENERATED_KEYS);
 //
 // Example of using Statement.getGeneratedKeys()
 // to retrieve the value of an auto-increment
 // value
 //
 int autoIncKeyFromApi = -1;
 rs = stmt.getGeneratedKeys();
 if (rs.next()) {
 autoIncKeyFromApi = rs.getInt(1);
 } else {
 // throw an exception from here
 }
 rs.close();
 rs = null;
 System.out.println('Key returned from getGeneratedKeys():'
 + autoIncKeyFromApi);
} finally {
 if (rs != null) {
 try {
 rs.close();
 } catch (SQLException ex) {
 // ignore
 }
 }
 if (stmt != null) {
 try {
 stmt.close();
 } catch (SQLException ex) {
 // ignore
 }
 }
}

Example 20.9. Connector/J: Retrieving AUTO_INCREMENT column values using SELECT LAST_INSERT_ID() 

 Statement stmt = null;
 ResultSet rs = null;
 try {
 //
 // Create a Statement instance that we can use for
 // 'normal' result sets.
 stmt = conn.createStatement();
 //
 // Issue the DDL queries for the table for this example
 //
 stmt.executeUpdate('DROP TABLE IF EXISTS autoIncTutorial');
 stmt.executeUpdate(
 'CREATE TABLE autoIncTutorial ('
 + 'priKey INT NOT NULL AUTO_INCREMENT, '
 + 'dataField VARCHAR(64), PRIMARY KEY (priKey))');
 //
 // Insert one row that will generate an AUTO INCREMENT
 // key in the 'priKey' field
 //
 stmt.executeUpdate(
 'INSERT INTO autoIncTutorial (dataField) '
 + 'values ('Can I Get the Auto Increment Field?')');
 //
 // Use the MariaDB LAST_INSERT_ID()
 // function to do the same thing as getGeneratedKeys()
 //
 int autoIncKeyFromFunc = -1;
 rs = stmt.executeQuery('SELECT LAST_INSERT_ID()');
 if (rs.next()) {
 autoIncKeyFromFunc = rs.getInt(1);
 } else {
 // throw an exception from here
 }
 rs.close();
 System.out.println('Key returned from ' +
 ''SELECT LAST_INSERT_ID()': ' +
 autoIncKeyFromFunc);
} finally {
 if (rs != null) {
 try {
 rs.close();
 } catch (SQLException ex) {
 // ignore
 }
 }
 if (stmt != null) {
 try {
 stmt.close();
 } catch (SQLException ex) {
 // ignore
 }
 }
}

Example 20.10. Connector/J: Retrieving AUTO_INCREMENT column values in Updatable ResultSets 

 Statement stmt = null;
 ResultSet rs = null;
 try {
 //
 // Create a Statement instance that we can use for
 // 'normal' result sets as well as an 'updatable'
 // one, assuming you have a Connection 'conn' to
 // a MariaDB database already available
 //
 stmt = conn.createStatement(java.sql.ResultSet.TYPE_FORWARD_ONLY,
 java.sql.ResultSet.CONCUR_UPDATABLE);
 //
 // Issue the DDL queries for the table for this example
 //
 stmt.executeUpdate('DROP TABLE IF EXISTS autoIncTutorial');
 stmt.executeUpdate(
 'CREATE TABLE autoIncTutorial ('
 + 'priKey INT NOT NULL AUTO_INCREMENT, '
 + 'dataField VARCHAR(64), PRIMARY KEY (priKey))');
 //
 // Example of retrieving an AUTO INCREMENT key
 // from an updatable result set
 //
 rs = stmt.executeQuery('SELECT priKey, dataField '
 + 'FROM autoIncTutorial');
 rs.moveToInsertRow();
 rs.updateString('dataField', 'AUTO INCREMENT here?');
 rs.insertRow();
 //
 // the driver adds rows at the end
 //
 rs.last();
 //
 // We should now be on the row we just inserted
 //
 int autoIncKeyFromRS = rs.getInt('priKey');
 rs.close();
 rs = null;
 System.out.println('Key returned for inserted row: '
 + autoIncKeyFromRS);
} finally {
 if (rs != null) {
 try {
 rs.close();
 } catch (SQLException ex) {
 // ignore
 }
 }
 if (stmt != null) {
 try {
 stmt.close();
 } catch (SQLException ex) {
 // ignore
 }
 }
}

Running the preceding example code should produce the following output: 

Key returned from getGeneratedKeys(): 1
Key returned from SELECT LAST_INSERT_ID(): 1
Key returned for inserted row: 2

At times, it can be tricky to use the SELECT LAST_INSERT_ID() query, as that function's value is scoped to a connection. So, if some other query happens on the same connection, the value is overwritten. On the other hand, the getGeneratedKeys() method is scoped by the Statement instance, so it can be used even if other queries happen on the same connection, but not on the same Statement instance.

J2EE Concepts

Understanding Connection Pooling
Managing Load Balanced Connections
Load Balancing Failover Policies

This section provides general background on J2EE concepts that pertain to use of Connector/J.

Understanding Connection Pooling

Connection pooling is a technique of creating and managing a pool of connections that are ready for use by any thread that needs them. Connection pooling can greatly increase the performance of your Java application, while reducing overall resource usage.

How Connection Pooling Works

Most applications only need a thread to have access to a JDBC connection when they are actively processing a transaction, which often takes only milliseconds to complete. When not processing a transaction, the connection sits idle. Connection pooling enables the idle connection to be used by some other thread to do useful work.

In practice, when a thread needs to do work against a MariaDB or other database with JDBC, it requests a connection from the pool. When the thread is finished using the connection, it returns it to the pool, so that it can be used by any other threads.

When the connection is loaned out from the pool, it is used exclusively by the thread that requested it. From a programming point of view, it is the same as if your thread called DriverManager.getConnection() every time it needed a JDBC connection. With connection pooling, your thread may end up using either a new connection or an already-existing connection.

Benefits of Connection Pooling

The main benefits to connection pooling are:

Using Connection Pooling with Connector/J

Sun has standardized the concept of connection pooling in JDBC through the JDBC-2.0 Optional interfaces, and all major application servers have implementations of these APIs that work with MariaDB Connector/J.

Generally, you configure a connection pool in your application server configuration files, and access it through the Java Naming and Directory Interface (JNDI). The following code shows how you might use a connection pool from an application deployed in a J2EE application server:

Example 20.11. Connector/J: Using a connection pool with a J2EE application server

import java.sql.Connection;
import java.sql.SQLException;
import java.sql.Statement;
import javax.naming.InitialContext;
import javax.sql.DataSource;
public class MyServletJspOrEjb {
 public void doSomething() throws Exception {
 /*
 * Create a JNDI Initial context to be able to
 * lookup the DataSource
 *
 * In production-level code, this should be cached as
 * an instance or static variable, as it can
 * be quite expensive to create a JNDI context.
 *
 * Note: This code only works when you are using servlets
 * or EJBs in a J2EE application server. If you are
 * using connection pooling in standalone Java code, you
 * will have to create/configure datasources using whatever
 * mechanisms your particular connection pooling library
 * provides.
 */
 InitialContext ctx = new InitialContext();
 /*
 * Lookup the DataSource, which will be backed by a pool
 * that the application server provides. DataSource instances
 * are also a good candidate for caching as an instance
 * variable, as JNDI lookups can be expensive as well.
 */
 DataSource ds =
 (DataSource)ctx.lookup('java:comp/env/jdbc/MySQLDB');
 /*
 * The following code is what would actually be in your
 * Servlet, JSP or EJB 'service' method...where you need
 * to work with a JDBC connection.
 */
 Connection conn = null;
 Statement stmt = null;
 try {
 conn = ds.getConnection();
 /*
 * Now, use normal JDBC programming to work with
 * MySQL, making sure to close each resource when you're
 * finished with it, which permits the connection pool
 * resources to be recovered as quickly as possible
 */
 stmt = conn.createStatement();
 stmt.execute('SOME SQL QUERY');
 stmt.close();
 stmt = null;
 conn.close();
 conn = null;
 } finally {
 /*
 * close any jdbc instances here that weren't
 * explicitly closed during normal code path, so
 * that we don't 'leak' resources...
 */
 if (stmt != null) {
 try {
 stmt.close();
 } catch (sqlexception sqlex) {
 // ignore -- as we can't do anything about it here
 }
 stmt = null;
 }
 if (conn != null) {
 try {
 conn.close();
 } catch (sqlexception sqlex) {
 // ignore -- as we can't do anything about it here
 }
 conn = null;
 }
 }
 }
}

As shown in the example above, after obtaining the JNDI InitialContext, and looking up the DataSource, the rest of the code follows familiar JDBC conventions.

When using connection pooling, always make sure that connections, and anything created by them (such as statements or result sets) are closed. This rule applies no matter what happens in your code (exceptions, flow-of-control, and so forth). When these objects are closed, they can be re-used; otherwise, they will be stranded, which means that the MariaDB server resources they represent (such as buffers, locks, or sockets) are tied up for some time, or in the worst case can be tied up forever.

Sizing the Connection Pool

Each connection to MariaDB has overhead (memory, CPU, context switches, and so forth) on both the client and server side. Every connection limits how many resources there are available to your application as well as the MariaDB server. Many of these resources will be used whether or not the connection is actually doing any useful work! Connection pools can be tuned to maximize performance, while keeping resource utilization below the point where your application will start to fail rather than just run slower.

The optimal size for the connection pool depends on anticipated load and average database transaction time. In practice, the optimal connection pool size can be smaller than you might expect. If you take Sun's Java Petstore blueprint application for example, a connection pool of 15-20 connections can serve a relatively moderate load (600 concurrent users) using MariaDB and Tomcat with acceptable response times.

To correctly size a connection pool for your application, create load test scripts with tools such as Apache JMeter or The Grinder, and load test your application.

An easy way to determine a starting point is to configure your connection pool's maximum number of connections to be unbounded, run a load test, and measure the largest amount of concurrently used connections. You can then work backward from there to determine what values of minimum and maximum pooled connections give the best performance for your particular application.

Validating Connections

MySQL Connector/J can validate the connection by executing a lightweight ping against a server. In the case of load-balanced connections, this is performed against all active pooled internal connections that are retained. This is beneficial to Java applications using connection pools, as the pool can use this feature to validate connections. Depending on your connection pool and configuration, this validation can be carried out at different times:

  1. Before the pool returns a connection to the application.
  2. When the application returns a connection to the pool.
  3. During periodic checks of idle connections.

To use this feature, specify a validation query in your connection pool that starts with /* ping */. Note that the syntax must be exactly as specified. This will cause the driver send a ping to the server and return a dummy lightweight result set. When using a ReplicationConnection or LoadBalancedConnection, the ping will be sent across all active connections.

It is critical that the syntax be specified correctly. The syntax needs to be exact for reasons of efficiency, as this test is done for every statement that is executed: 

protected static final String PING_MARKER = '/* ping */';
...
if (sql.charAt(0) == '/') {
if (sql.startsWith(PING_MARKER)) {
doPingInstead();
...

None of the following snippets will work, because the ping syntax is sensitive to whitespace, capitalization, and placement: 

sql = '/* PING */ SELECT 1';
sql = 'SELECT 1 /* ping*/';
sql = '/*ping*/ SELECT 1';
sql = ' /* ping */ SELECT 1';
sql = '/*to ping or not to ping*/ SELECT 1';

All of the previous statements will issue a normal SELECT statement and will not be transformed into the lightweight ping. Further, for load-balanced connections, the statement will be executed against one connection in the internal pool, rather than validating each underlying physical connection. This results in the non-active physical connections assuming a stale state, and they may die. If Connector/J then re-balances, it might select a dead connection, resulting in an exception being passed to the application. To help prevent this, you can use loadBalanceValidateConnectionOnSwapServer to validate the connection before use.

If your Connector/J deployment uses a connection pool that allows you to specify a validation query, take advantage of it, but ensure that the query starts exactly with /* ping */. This is particularly important if you are using the load-balancing or replication-aware features of Connector/J, as it will help keep alive connections which otherwise will go stale and die, causing problems later.

Managing Load Balanced Connections

Connector/J has long provided an effective means to distribute read/write load across multiple MariaDB server instances for Cluster or master-master replication deployments. Starting with Connector/J 5.1.3, you can now dynamically configure load-balanced connections, with no service outage. In-process transactions are not lost, and no application exceptions are generated if any application is trying to use that particular server instance.

There are two connection string options associated with this functionality:

Once a connection has been made using the correct connection string options, a number of monitoring properties are available:

The following management operations can also be performed:

The JMX interface, com.mysql.jdbc.jmx.LoadBalanceConnectionGroupManagerMBean, has the following methods:

The getRegisteredConnectionGroups() method returns the names of all connection groups defined in that class-loader.

You can test this setup with the following code: 

public class Test {
 private static String URL = 'jdbc:mysql:loadbalance://' +
 'localhost:3306,localhost:3310/test?' +
 'loadBalanceConnectionGroup=first&loadBalanceEnableJMX=true';
 public static void main(String[] args) throws Exception {
 new Thread(new Repeater()).start();
 new Thread(new Repeater()).start();
 new Thread(new Repeater()).start();
 }
 static Connection getNewConnection() throws SQLException, ClassNotFoundException {
 Class.forName('com.mysql.jdbc.Driver');
 return DriverManager.getConnection(URL, 'root', '');
 }
 static void executeSimpleTransaction(Connection c, int conn, int trans){
 try {
 c.setAutoCommit(false);
 Statement s = c.createStatement();
 s.executeQuery('SELECT SLEEP(1) /* Connection: ' + conn + ', transaction: ' + trans + ' */');
 c.commit();
 } catch (SQLException e) {
 e.printStackTrace();
 }
 }
 public static class Repeater implements Runnable {
 public void run() {
 for(int i=0; i < 100; i++){
 try {
 Connection c = getNewConnection();
 for(int j=0; j < 10; j++){
 executeSimpleTransaction(c, i, j);
 Thread.sleep(Math.round(100 * Math.random()));
 }
 c.close();
 Thread.sleep(100);
 } catch (Exception e) {
 e.printStackTrace();
 }
 }
 }
 }
}

After compiling, the application can be started with the -Dcom.sun.management.jmxremote flag, to enable remote management. jconsole can then be started. The Test main class will be listed by jconsole. Select this and click Connect. You can then navigate to the com.mysql.jdbc.jmx.LoadBalanceConnectionGroupManager bean. At this point, you can click on various operations and examine the returned result.

If you now had an additional instance of MariaDB running on port 3309, you could ensure that Connector/J starts using it by using the addHost(), which is exposed in jconsole. Note that these operations can be performed dynamically without having to stop the application running.

Load Balancing Failover Policies

Connector/J provides a useful load-balancing implementation for Cluster or multi-master deployments. As of Connector/J 5.1.12, this same implementation is used for balancing load between read-only slaves with ReplicationDriver. When trying to balance workload between multiple servers, the driver has to determine when it is safe to swap servers, doing so in the middle of a transaction, for example, could cause problems. It is important not to lose state information. For this reason, Connector/J will only try to pick a new server when one of the following happens:

  1. At transaction boundaries (transactions are explicitly committed or rolled back).
  2. A communication exception (SQL State starting with '08') is encountered.
  3. When a SQLException matches conditions defined by user, using the extension points defined by the loadBalanceSQLStateFailover, loadBalanceSQLExceptionSubclassFailover or loadBalanceExceptionChecker properties.

The third condition revolves around three new properties introduced with Connector/J 5.1.13. It allows you to control which SQLExceptions trigger failover.

While the three fail-over conditions enumerated earlier suit most situations, if auto-commit is enabled, Connector/J never re-balances, and continues using the same physical connection. This can be problematic, particularly when load-balancing is being used to distribute read-only load across multiple slaves. However, Connector/J can be configured to re-balance after a certain number of statements are executed, when auto-commit is enabled. This functionality is dependent upon the following properties:

Using Connector/J with Tomcat

The following instructions are based on the instructions for Tomcat-5.x, available at http://tomcat.apache.org/tomcat-5.5-doc/jndi-datasource-examples-howto.html which is current at the time this document was written.

First, install the .jar file that comes with Connector/J in $CATALINA_HOME/common/lib so that it is available to all applications installed in the container.

Next, Configure the JNDI DataSource by adding a declaration resource to $CATALINA_HOME/conf/server.xml in the context that defines your web application: 

 <Context ....>
 ...
 <Resource name="jdbc/MySQLDB"
 auth="Container"
 type="javax.sql.DataSource"/>
 <!-- The name you used above, must match _exactly_ here!
 The connection pool will be bound into JNDI with the name
 'java:/comp/env/jdbc/MySQLDB'
 -->
 <ResourceParams name="jdbc/MySQLDB">
 <parameter>
 <name>factory</name>
 <value>org.apache.commons.dbcp.BasicDataSourceFactory</value>
 </parameter>
 <!-- Don't set this any higher than max_connections on your
 MariaDB server, usually this should be a 10 or a few 10's
 of connections, not hundreds or thousands -->
 <parameter>
 <name>maxActive</name>
 <value>10</value>
 </parameter>
 <!-- You don't want to many idle connections hanging around
 if you can avoid it, only enough to soak up a spike in
 the load -->
 <parameter>
 <name>maxIdle</name>
 <value>5</value>
 </parameter>
 <!-- Don't use autoReconnect=true, it's going away eventually
 and it's a crutch for older connection pools that couldn't
 test connections. You need to decide whether your application
 is supposed to deal with SQLExceptions (hint, it should), and
 how much of a performance penalty you're willing to pay
 to ensure 'freshness' of the connection -->
 <parameter>
 <name>validationQuery</name>
 <value>SELECT 1</value> <-- See discussion below for update to this option -->
 </parameter>
 <!-- The most conservative approach is to test connections
 before they're given to your application. For most applications
 this is okay, the query used above is very small and takes
 no real server resources to process, other than the time used
 to traverse the network.
 If you have a high-load application you'll need to rely on
 something else. -->
 <parameter>
 <name>testOnBorrow</name>
 <value>true</value>
 </parameter>
 <!-- Otherwise, or in addition to testOnBorrow, you can test
 while connections are sitting idle -->
 <parameter>
 <name>testWhileIdle</name>
 <value>true</value>
 </parameter>
 <!-- You have to set this value, otherwise even though
 you've asked connections to be tested while idle,
 the idle evicter thread will never run -->
 <parameter>
 <name>timeBetweenEvictionRunsMillis</name>
 <value>10000</value>
 </parameter>
 <!-- Don't allow connections to hang out idle too long,
 never longer than what wait_timeout is set to on the
 server...A few minutes or even fraction of a minute
 is sometimes okay here, it depends on your application
 and how much spikey load it will see -->
 <parameter>
 <name>minEvictableIdleTimeMillis</name>
 <value>60000</value>
 </parameter>
 <!-- Username and password used when connecting to MariaDB -->
 <parameter>
 <name>username</name>
 <value>someuser</value>
 </parameter>
 <parameter>
 <name>password</name>
 <value>somepass</value>
 </parameter>
 <!-- Class name for the Connector/J driver -->
 <parameter>
 <name>driverClassName</name>
 <value>com.mysql.jdbc.Driver</value>
 </parameter>
 <!-- The JDBC connection url for connecting to MySQL, notice
 that if you want to pass any other MySQL-specific parameters
 you should pass them here in the URL, setting them using the
 parameter tags above will have no effect, you will also
 need to use &amp; to separate parameter values as the
 ampersand is a reserved character in XML -->
 <parameter>
 <name>url</name>
 <value>jdbc:mysql://localhost:3306/test</value>
 </parameter>
 </ResourceParams>
</Context>

Note that Connector/J 5.1.3 introduced a facility whereby, rather than use a validationQuery value of SELECT 1, it is possible to use validationQuery with a value set to /* ping */. This sends a ping to the server which then returns a fake result set. This is a lighter weight solution. It also has the advantage that if using ReplicationConnection or LoadBalancedConnection type connections, the ping will be sent across all active connections. The following XML snippet illustrates how to select this option: 

<parameter>
 <name>validationQuery</name>
 <value>/* ping */</value>
</parameter>

Note that /* ping */ has to be specified exactly.

In general, follow the installation instructions that come with your version of Tomcat, as the way you configure datasources in Tomcat changes from time-to-time, and if you use the wrong syntax in your XML file, you will most likely end up with an exception similar to the following: 

Error: java.sql.SQLException: Cannot load JDBC driver class 'null ' SQL state: null

Note that the auto-loading of drivers having the META-INF/service/java.sql.Driver class in JDBC 4.0 causes an improper undeployment of the Connector/J driver in Tomcat on Windows. Namely, the Connector/J jar remains locked. This is an initialization problem that is not related to the driver. The possible workarounds, if viable, are as follows: use 'antiResourceLocking=true' as a Tomcat Context attribute, or remove the META-INF/ directory.

Using Connector/J with JBoss

These instructions cover JBoss-4.x. To make the JDBC driver classes available to the application server, copy the .jar file that comes with Connector/J to the lib directory for your server configuration (which is usually called default). Then, in the same configuration directory, in the subdirectory named deploy, create a datasource configuration file that ends with '-ds.xml', which tells JBoss to deploy this file as a JDBC Datasource. The file should have the following contents: 

<datasources>
 <local-tx-datasource>
 <!-- This connection pool will be bound into JNDI with the name
 'java:/MySQLDB' -->
 <jndi-name>MySQLDB</jndi-name>
 <connection-url>jdbc:mysql://localhost:3306/dbname</connection-url>
 <driver-class>com.mysql.jdbc.Driver</driver-class>
 <user-name>user</user-name>
 <password>pass</password>
 <min-pool-size>5</min-pool-size>
 <!-- Don't set this any higher than max_connections on your
 MariaDB server, usually this should be a 10 or a few 10's
 of connections, not hundreds or thousands -->
 <max-pool-size>20</max-pool-size>
 <!-- Don't allow connections to hang out idle too long,
 never longer than what wait_timeout is set to on the
 server...A few minutes is usually okay here,
 it depends on your application
 and how much spikey load it will see -->
 <idle-timeout-minutes>5</idle-timeout-minutes>
 <!-- If you're using Connector/J 3.1.8 or newer, you can use
 our implementation of these to increase the robustness
 of the connection pool. -->
 <exception-sorter-class-name>
 com.mysql.jdbc.integration.jboss.ExtendedMysqlExceptionSorter
 </exception-sorter-class-name>
 <valid-connection-checker-class-name>
 com.mysql.jdbc.integration.jboss.MysqlValidConnectionChecker
 </valid-connection-checker-class-name>
 </local-tx-datasource>
</datasources>

Using Connector/J with Spring

Using JdbcTemplate
Transactional JDBC Access
Connection Pooling with Spring

The Spring Framework is a Java-based application framework designed for assisting in application design by providing a way to configure components. The technique used by Spring is a well known design pattern called Dependency Injection (see Inversion of Control Containers and the Dependency Injection pattern). This article will focus on Java-oriented access to MariaDB databases with Spring 2.0. For those wondering, there is a .NET port of Spring appropriately named Spring.NET.

Spring is not only a system for configuring components, but also includes support for aspect oriented programming (AOP). This is one of the main benefits and the foundation for Spring's resource and transaction management. Spring also provides utilities for integrating resource management with JDBC and Hibernate.

For the examples in this section the MariaDB world sample database will be used. The first task is to set up a MariaDB data source through Spring. Components within Spring use the 'bean' terminology. For example, to configure a connection to a MariaDB server supporting the world sample database you might use: 

<util:map id="dbProps">
 <entry key="db.driver" value="com.mysql.jdbc.Driver"/>
 <entry key="db.jdbcurl" value="jdbc:mysql://localhost/world"/>
 <entry key="db.username" value="myuser"/>
 <entry key="db.password" value="mypass"/>
</util:map>

In the above example we are assigning values to properties that will be used in the configuration. For the datasource configuration: 

<bean id="dataSource"
 class="org.springframework.jdbc.datasource.DriverManagerDataSource">
 <property name="driverClassName" value="${db.driver}"/>
 <property name="url" value="${db.jdbcurl}"/>
 <property name="username" value="${db.username}"/>
 <property name="password" value="${db.password}"/>
</bean>

The placeholders are used to provide values for properties of this bean. This means that you can specify all the properties of the configuration in one place instead of entering the values for each property on each bean. We do, however, need one more bean to pull this all together. The last bean is responsible for actually replacing the placeholders with the property values. 

<bean
 class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
 <property name="properties" ref="dbProps"/>
</bean>

Now that we have our MariaDB data source configured and ready to go, we write some Java code to access it. The example below will retrieve three random cities and their corresponding country using the data source we configured with Spring. 

// Create a new application context. this processes the Spring config ApplicationContext ctx =
 new ClassPathXmlApplicationContext('ex1appContext.xml');
// Retrieve the data source from the application context
 DataSource ds = (DataSource) ctx.getBean('dataSource');
// Open a database connection using Spring's DataSourceUtils Connection c = DataSourceUtils.getConnection(ds);
try {
 // retrieve a list of three random cities
 PreparedStatement ps = c.prepareStatement(
 'select City.Name as 'City', Country.Name as 'Country' ' +
 'from City inner join Country on City.CountryCode = Country.Code ' +
 'order by rand() limit 3');
 ResultSet rs = ps.executeQuery();
 while(rs.next()) {
 String city = rs.getString('City');
 String country = rs.getString('Country');
 System.out.printf('The city %s is in %s%n', city, country);
 }
} catch (SQLException ex) {
 // something has failed and we print a stack trace to analyse the error
 ex.printStackTrace();
 // ignore failure closing connection
 try { c.close(); } catch (SQLException e) { }
} finally {
 // properly release our connection
 DataSourceUtils.releaseConnection(c, ds);
}

This is very similar to normal JDBC access to MariaDB with the main difference being that we are using DataSourceUtils instead of the DriverManager to create the connection.

While it may seem like a small difference, the implications are somewhat far reaching. Spring manages this resource in a way similar to a container managed data source in a J2EE application server. When a connection is opened, it can be subsequently accessed in other parts of the code if it is synchronized with a transaction. This makes it possible to treat different parts of your application as transactional instead of passing around a database connection.

Using JdbcTemplate

Spring makes extensive use of the Template method design pattern (see Template Method Pattern). Our immediate focus will be on the JdbcTemplate and related classes, specifically NamedParameterJdbcTemplate. The template classes handle obtaining and releasing a connection for data access when one is needed.

The next example shows how to use NamedParameterJdbcTemplate inside of a DAO (Data Access Object) class to retrieve a random city given a country code. 

public class Ex2JdbcDao {
 /**
 * Data source reference which will be provided by Spring.
 */
 private DataSource dataSource;
 /**
 * Our query to find a random city given a country code. Notice
 * the ':country' parameter toward the end. This is called a
 * named parameter.
 */
 private String queryString = 'select Name from City ' +
 'where CountryCode = :country order by rand() limit 1';
 /**
 * Retrieve a random city using Spring JDBC access classes.
 */
 public String getRandomCityByCountryCode(String cntryCode) {
 // A template that permits using queries with named parameters
 NamedParameterJdbcTemplate template =
 new NamedParameterJdbcTemplate(dataSource);
 // A java.util.Map is used to provide values for the parameters
 Map params = new HashMap();
 params.put('country', cntryCode);
 // We query for an Object and specify what class we are expecting
 return (String)template.queryForObject(queryString, params, String.class);
 }
 /**
 * A JavaBean setter-style method to allow Spring to inject the data source.
 * @param dataSource
 */
 public void setDataSource(DataSource dataSource) {
 this.dataSource = dataSource;
 }
}

The focus in the above code is on the getRandomCityByCountryCode() method. We pass a country code and use the NamedParameterJdbcTemplate to query for a city. The country code is placed in a Map with the key 'country', which is the parameter is named in the SQL query.

To access this code, you need to configure it with Spring by providing a reference to the data source. 

<bean id="dao" class="code.Ex2JdbcDao">
 <property name="dataSource" ref="dataSource"/>
</bean>

At this point, we can just grab a reference to the DAO from Spring and call getRandomCityByCountryCode(). 

 // Create the application context
 ApplicationContext ctx =
 new ClassPathXmlApplicationContext('ex2appContext.xml');
 // Obtain a reference to our DAO
 Ex2JdbcDao dao = (Ex2JdbcDao) ctx.getBean('dao');
 String countryCode = 'USA';
 // Find a few random cities in the US
 for(int i = 0; i < 4; ++i)
 System.out.printf('A random city in %s is %s%n', countryCode,
 dao.getRandomCityByCountryCode(countryCode));

This example shows how to use Spring's JDBC classes to completely abstract away the use of traditional JDBC classes including Connection and PreparedStatement.

Transactional JDBC Access

You might be wondering how we can add transactions into our code if we do not deal directly with the JDBC classes. Spring provides a transaction management package that not only replaces JDBC transaction management, but also enables declarative transaction management (configuration instead of code).

To use transactional database access, we will need to change the storage engine of the tables in the world database. The downloaded script explicitly creates MyISAM tables which do not support transactional semantics. The InnoDB storage engine does support transactions and this is what we will be using. We can change the storage engine with the following statements. 

ALTER TABLE City ENGINE=InnoDB;
ALTER TABLE Country ENGINE=InnoDB;
ALTER TABLE CountryLanguage ENGINE=InnoDB;

A good programming practice emphasized by Spring is separating interfaces and implementations. What this means is that we can create a Java interface and only use the operations on this interface without any internal knowledge of what the actual implementation is. We will let Spring manage the implementation and with this it will manage the transactions for our implementation.

First you create a simple interface: 

public interface Ex3Dao {
 Integer createCity(String name, String countryCode,
 String district, Integer population);
}

This interface contains one method that will create a new city record in the database and return the id of the new record. Next you need to create an implementation of this interface. 

public class Ex3DaoImpl implements Ex3Dao {
 protected DataSource dataSource;
 protected SqlUpdate updateQuery;
 protected SqlFunction idQuery;
 public Integer createCity(String name, String countryCode,
 String district, Integer population) {
 updateQuery.update(new Object[] { name, countryCode,
 district, population });
 return getLastId();
 }
 protected Integer getLastId() {
 return idQuery.run();
 }
}

You can see that we only operate on abstract query objects here and do not deal directly with the JDBC API. Also, this is the complete implementation. All of our transaction management will be dealt with in the configuration. To get the configuration started, we need to create the DAO. 

<bean id="dao" class="code.Ex3DaoImpl">
 <property name="dataSource" ref="dataSource"/>
 <property name="updateQuery">...</property>
 <property name="idQuery">...</property>
</bean>

Now you need to set up the transaction configuration. The first thing you must do is create transaction manager to manage the data source and a specification of what transaction properties are required for the dao methods. 

<bean id="transactionManager"
 class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
 <property name="dataSource" ref="dataSource"/>
</bean>
<tx:advice id="txAdvice" transaction-manager='transactionManager'>
 <tx:attributes>
 <tx:method name="*"/>
 </tx:attributes>
</tx:advice>

The preceding code creates a transaction manager that handles transactions for the data source provided to it. The txAdvice uses this transaction manager and the attributes specify to create a transaction for all methods. Finally you need to apply this advice with an AOP pointcut. 

<aop:config>
 <aop:pointcut id="daoMethods"
 expression="execution(* code.Ex3Dao.*(..))"/>
 <aop:advisor advice-ref='txAdvice' pointcut-ref='daoMethods'/>
</aop:config>

This basically says that all methods called on the Ex3Dao interface will be wrapped in a transaction. To make use of this, you only have to retrieve the dao from the application context and call a method on the dao instance. 

Ex3Dao dao = (Ex3Dao) ctx.getBean('dao');
Integer id = dao.createCity(name, countryCode, district, pop);

We can verify from this that there is no transaction management happening in our Java code and it is all configured with Spring. This is a very powerful notion and regarded as one of the most beneficial features of Spring.

Connection Pooling with Spring

In many situations, such as web applications, there will be a large number of small database transactions. When this is the case, it usually makes sense to create a pool of database connections available for web requests as needed. Although MariaDB does not spawn an extra process when a connection is made, there is still a small amount of overhead to create and set up the connection. Pooling of connections also alleviates problems such as collecting large amounts of sockets in the TIME_WAIT state.

Setting up pooling of MariaDB connections with Spring is as simple as changing the data source configuration in the application context. There are a number of configurations that we can use. The first example is based on the Jakarta Commons DBCP library. The example below replaces the source configuration that was based on DriverManagerDataSource with DBCP's BasicDataSource. 

<bean id="dataSource" destroy-method='close'
 class="org.apache.commons.dbcp.BasicDataSource">
 <property name="driverClassName" value="${db.driver}"/>
 <property name="url" value="${db.jdbcurl}"/>
 <property name="username" value="${db.username}"/>
 <property name="password" value="${db.password}"/>
 <property name="initialSize" value="3"/>
</bean>

The configuration of the two solutions is very similar. The difference is that DBCP will pool connections to the database instead of creating a new connection every time one is requested. We have also set a parameter here called initialSize. This tells DBCP that we want three connections in the pool when it is created.

Another way to configure connection pooling is to configure a data source in our J2EE application server. Using JBoss as an example, you can set up the MariaDB connection pool by creating a file called mysql-local-ds.xml and placing it in the server/default/deploy directory in JBoss. Once we have this setup, we can use JNDI to look it up. With Spring, this lookup is very simple. The data source configuration looks like this. 

<jee:jndi-lookup id="dataSource" jndi-name='java:MySQL_DS'/>

Using Connector/J with GlassFish

A Simple JSP Application with Glassfish, Connector/J and MySQL
A Simple Servlet with Glassfish, Connector/J and MySQL

This section explains how to use MariaDB Connector/J with Glassfish Server Open Source Edition 3.0.1. Glassfish can be downloaded from the Glassfish website.

Once Glassfish is installed you will need to make sure it can access MariaDB Connector/J. To do this copy the MariaDB Connector/J JAR file to the directory GLASSFISH_INSTALL/glassfish/lib. For example, copy mysql-connector-java-5.1.12-bin.jar to C:\glassfishv3\glassfish\lib. Restart the Glassfish Application Server.

You are now ready to create JDBC Connection Pools and JDBC Resources.

Creating a Connection Pool

  1. In the Glassfish Administration Console, using the navigation tree navigate to Resources, JDBC, Connection Pools.
  2. In the JDBC Connection Pools frame click New. You will enter a two step wizard.
  3. In the Name field under General Settings enter the name for the connection pool, for example enter MySQLConnPool.
  4. In the Resource Type field, select javax.sql.DataSource from the drop-down listbox.
  5. In the Database Vendor field, select MariaDB from the drop-down listbox. Click Next to go to the next page of the wizard.
  6. You can accept the default settings for General Settings, Pool Settings and Transactions for this example. Scroll down to Additional Properties.
  7. In Additional Properties you will need to ensure the following properties are set:
    • ServerName - The server to connect to. For local testing this will be localhost.
    • User - The user name with which to connect to MariaDB.
    • Password - The corresponding password for the user.
    • DatabaseName - The database to connect to, for example the sample MariaDB database World.
  8. Click Finish to exit the wizard. You will be taken to the JDBC Connection Pools page where all current connection pools, including the one you just created, will be displayed.
  9. In the JDBC Connection Pools frame click on the connection pool you just created. Here you can review and edit information about the connection pool.
  10. To test your connection pool click the Ping button at the top of the frame. A message will be displayed confirming correct operation or otherwise. If an error message is received recheck the previous steps, and ensure that MariaDB Connector/J has been correctly copied into the previously specified location.

Now that you have created a connection pool you will also need to create a JDBC Resource (data source) for use by your application.

Creating a JDBC Resource

Your Java application will usually reference a data source object to establish a connection with the database. This needs to be created first using the following procedure.

A Simple JSP Application with Glassfish, Connector/J and MariaDB

This section shows how to deploy a simple JSP application on Glassfish, that connects to a MariaDB database.

This example assumes you have already set up a suitable Connection Pool and JDBC Resource, as explained in the preceding sections. It is also assumed you have a sample database installed, such as world.

The main application code, index.jsp is presented here: 

<%@ page import="java.sql.*, javax.sql.*, java.io.*, javax.naming.*" %>
<html>
<head><title>Hello world from JSP</title></head>
<body>
<%
 InitialContext ctx;
 DataSource ds;
 Connection conn;
 Statement stmt;
 ResultSet rs;
 try {
 ctx = new InitialContext();
 ds = (DataSource) ctx.lookup('java:comp/env/jdbc/MySQLDataSource');
 //ds = (DataSource) ctx.lookup('jdbc/MySQLDataSource');
 conn = ds.getConnection();
 stmt = conn.createStatement();
 rs = stmt.executeQuery('SELECT * FROM Country');
 while(rs.next()) {
%>
 <h3>Name: <%= rs.getString('Name') %></h3>
 <h3>Population: <%= rs.getString('Population') %></h3>
<% 
 }
 }
 catch (SQLException se) {
%>
 <%= se.getMessage() %>
<% 
 }
 catch (NamingException ne) {
%> 
 <%= ne.getMessage() %>
<%
 }
%>
</body>
</html>

In addition two XML files are required: web.xml, and sun-web.xml. There may be other files present, such as classes and images. These files are organized into the directory structure as follows: 

index.jsp WEB-INF
 |
 - web.xml
 - sun-web.xml

The code for web.xml is: 

<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.4" xmlns="http://java.sun.com/xml/ns/j2ee" xmlns:xsi='http://www.w3.org/2001/XMLSchema-instance' xsi:schemaLocation='http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd'>
 <display-name>HelloWebApp</display-name> 
 <distributable/>
 <resource-ref>
 <res-ref-name>jdbc/MySQLDataSource</res-ref-name>
 <res-type>javax.sql.DataSource</res-type>
 <res-auth>Container</res-auth>
 <res-sharing-scope>Shareable</res-sharing-scope> 
 </resource-ref>
</web-app>

The code for sun-web.xml is: 

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE sun-web-app PUBLIC '-//Sun Microsystems, Inc.//DTD Application Server 8.1 Servlet 2.4//EN' 'http://www.sun.com/software/appserver/dtds/sun-web-app_2_4-1.dtd'>
<sun-web-app>
 <context-root>HelloWebApp</context-root>
 <resource-ref>
 <res-ref-name>jdbc/MySQLDataSource</res-ref-name>
 <jndi-name>jdbc/MySQLDataSource</jndi-name> 
 </resource-ref> 
</sun-web-app>

These XML files illustrate a very important aspect of running JDBC applications on Glassfish. On Glassfish it is important to map the string specified for a JDBC resource to its JNDI name, as set up in the Glassfish administration console. In this example, the JNDI name for the JDBC resource, as specified in the Glassfish Administration console when creating the JDBC Resource, was jdbc/MySQLDataSource. This must be mapped to the name given in the application. In this example the name specified in the application, jdbc/MySQLDataSource, and the JNDI name, happen to be the same, but this does not necessarily have to be the case. Note that the XML element <res-ref-name> is used to specify the name as used in the application source code, and this is mapped to the JNDI name specified using the <jndi-name> element, in the file sun-web.xml. The resource also has to be created in the web.xml file, although the mapping of the resource to a JNDI name takes place in the sun-web.xml file.

If you do not have this mapping set up correctly in the XML files you will not be able to lookup the data source using a JNDI lookup string such as: 

ds = (DataSource) ctx.lookup('java:comp/env/jdbc/MySQLDataSource');

You will still be able to access the data source directly using: 

ds = (DataSource) ctx.lookup('jdbc/MySQLDataSource');

With the source files in place, in the correct directory structure, you are ready to deploy the application:

  1. In the navigation tree, navigate to Applications - the Applications frame will be displayed. Click Deploy.
  2. You can now deploy an application packaged into a single WAR file from a remote client, or you can choose a packaged file or directory that is locally accessible to the server. If you are simply testing an application locally you can simply point Glassfish at the directory that contains your application, without needing to package the application into a WAR file.
  3. Now select the application type from the Type drop-down listbox, which in this example is Web application.
  4. Click OK.

Now, when you navigate to the Applications frame, you will have the option to Launch, Redeploy, or Restart your application. You can test your application by clicking Launch. The application will connection to the MariaDB database and display the Name and Population of countries in the Country table.

A Simple Servlet with Glassfish, Connector/J and MariaDB

This section describes a simple servlet that can be used in the Glassfish environment to access a MariaDB database. As with the previous section, this example assumes the sample database world is installed.

The project is set up with the following directory structure: 

index.html WEB-INF
 |
 - web.xml
 - sun-web.xml
 - classes
 |
 - HelloWebServlet.java
 - HelloWebServlet.class

The code for the servlet, located in HelloWebServlet.java, is as follows: 

import javax.servlet.http.*;
import javax.servlet.*;
import java.io.*;
import java.sql.*;
import javax.sql.*;
import javax.naming.*;
public class HelloWebServlet extends HttpServlet {
 InitialContext ctx = null;
 DataSource ds = null;
 Connection conn = null;
 PreparedStatement ps = null;
 ResultSet rs = null;
 String sql = 'SELECT Name, Population FROM Country WHERE Name=?';
 public void init () throws ServletException {
 try {
 ctx = new InitialContext();
 ds = (DataSource) ctx.lookup('java:comp/env/jdbc/MySQLDataSource');
 conn = ds.getConnection();
 ps = conn.prepareStatement(sql);
 }
 catch (SQLException se) {
 System.out.println('SQLException: '+se.getMessage());
 }
 catch (NamingException ne) {
 System.out.println('NamingException: '+ne.getMessage()); 
 } 
 }
 public void destroy () {
 try {
 if (rs != null)
 rs.close();
 if (ps != null)
 ps.close();
 if (conn != null)
 conn.close();
 if (ctx != null)
 ctx.close(); 
 } 
 catch (SQLException se) {
 System.out.println('SQLException: '+se.getMessage());
 }
 catch (NamingException ne) {
 System.out.println('NamingException: '+ne.getMessage()); 
 } 
 }
 public void doPost(HttpServletRequest req, HttpServletResponse resp){
 try {
 String country_name = req.getParameter('country_name'); 
 resp.setContentType('text/html');
 PrintWriter writer = resp.getWriter();
 writer.println('<html><body>');
 writer.println('<p>Country: '+country_name+'</p>');
 ps.setString(1, country_name);
 rs = ps.executeQuery();
 if (!rs.next()){
 writer.println('<p>Country does not exist!</p>');
 }
 else {
 rs.beforeFirst();
 while(rs.next()) {
 writer.println('<p>Name: '+rs.getString('Name')+'</p>');
 writer.println('<p>Population: '+rs.getString('Population')+'</p>');
 }
 }
 writer.println('</body></html>');
 writer.close(); 
 }
 catch (Exception e) {
 e.printStackTrace();
 } 
 }
 public void doGet(HttpServletRequest req, HttpServletResponse resp){
 try { 
 resp.setContentType('text/html');
 PrintWriter writer = resp.getWriter();
 writer.println('<html><body>');
 writer.println('<p>Hello from servlet doGet()</p>');
 writer.println('</body></html>');
 writer.close(); 
 }
 catch (Exception e) {
 e.printStackTrace();
 } 
 }
}

In the preceding code a basic doGet() method is implemented, but is not used in the example. The code to establish the connection with the database is as shown in the previous example, , "A Simple JSP Application with Glassfish, Connector/J and MySQL", and is most conveniently located in the servlet init() method. The corresponding freeing of resources is located in the destroy method. The main functionality of the servlet is located in the doPost() method. If the user enters nto the input form a country name that can be located in the database, the population of the country is returned. The code is invoked using a POST action associated with the input form. The form is defined in the file index.html: 

<html>
 <head><title>HelloWebServlet</title></head>
 <body>
 <h1>HelloWebServlet</h1>
 <p>Please enter country name:</p>
 <form action="HelloWebServlet" method="POST">
 <input type="text" name="country_name" length="50" />
 <input type="submit" value="Submit" />
 </form>
 </body>
</html>

The XML files web.xml and sun-web.xml are as for the example in the preceding section, , "A Simple JSP Application with Glassfish, Connector/J and MySQL", no additional changes are required.

Whe compiling the Java source code, you will need to specify the path to the file javaee.jar. On Windows, this can be done as follows: 

shell> javac -classpath c:\glassfishv3\glassfish\lib\javaee.jar HelloWebServlet.java

Once the code is correctly located within its directory structure, and compiled, the application can be deployed in Glassfish. This is done in exactly the same way as described in the preceding section, , "A Simple JSP Application with Glassfish, Connector/J and MySQL".

Once deployed the application can be launched from within the Glassfish Administration Console. Enter a country name such as "England", and the application will return "Country does not exist!". Enter "France", and the application will return a population of 59225700.

Troubleshooting Connector/J

There are a few issues that seem to be commonly encountered often by users of MariaDB Connector/J. This section deals with their symptoms, and their resolutions.

Questions

Questions and Answers

21.3.12.1: When I try to connect to the database with MariaDB Connector/J, I get the following exception: 

SQLException: Server configuration denies access to data source SQLState: 08001
VendorError: 0

What is going on? I can connect just fine with the MariaDB command-line client.

MySQL Connector/J must use TCP/IP sockets to connect to MySQL, as Java does not support Unix Domain Sockets. Therefore, when MariaDB Connector/J connects to MySQL, the security manager in MariaDB server will use its grant tables to determine whether the connection is permitted.

You must add the necessary security credentials to the MariaDB server for this to happen, using the GRANT statement to your MariaDB Server. See , "GRANT Syntax", for more information.Note

Testing your connectivity with the mysql command-line client will not work unless you add the --host flag, and use something other than localhost for the host. The mysql command-line client will use Unix domain sockets if you use the special host name localhost. If you are testing connectivity to localhost, use 127.0.0.1 as the host name instead.Warning

Changing privileges and permissions improperly in MariaDB can potentially cause your server installation to not have optimal security properties.

21.3.12.2: My application throws an SQLException 'No Suitable Driver'. Why is this happening?

There are three possible causes for this error:

21.3.12.3: I'm trying to use MariaDB Connector/J in an applet or application and I get an exception similar to: 

SQLException: Cannot connect to MariaDB server on host:3306.
Is there a MariaDB server running on the machine/port you are trying to connect to?
(java.security.AccessControlException)
SQLState: 08S01
VendorError: 0

Either you're running an Applet, your MariaDB server has been installed with the '--skip-networking' option set, or your MariaDB server has a firewall sitting in front of it.

Applets can only make network connections back to the machine that runs the web server that served the .class files for the applet. This means that MariaDB must run on the same machine (or you must have some sort of port re-direction) for this to work. This also means that you will not be able to test applets from your local file system, you must always deploy them to a web server.

MySQL Connector/J can only communicate with MariaDB using TCP/IP, as Java does not support Unix domain sockets. TCP/IP communication with MariaDB might be affected if MariaDB was started with the '--skip-networking' flag, or if it is firewalled.

If MariaDB has been started with the '--skip-networking' option set (the Debian Linux package of MariaDB server does this for example), you need to comment it out in the file /etc/mysql/my.cnf or /etc/my.cnf. Of course your my.cnf file might also exist in the data directory of your MariaDB server, or anywhere else (depending on how MariaDB was compiled for your system). Binaries created by us always look in /etc/my.cnf and [datadir]/my.cnf. If your MariaDB server has been firewalled, you will need to have the firewall configured to allow TCP/IP connections from the host where your Java code is running to the MariaDB server on the port that MariaDB is listening to (by default, 3306).

21.3.12.4: I have a servlet/application that works fine for a day, and then stops working overnight

MySQL closes connections after 8 hours of inactivity. You either need to use a connection pool that handles stale connections or use the 'autoReconnect' parameter (see , "Driver/Datasource Class Names, URL Syntax and Configuration Properties for Connector/J").

Also, catch SQLExceptions in your application and deal with them, rather than propagating them all the way until your application exits. This is just good programming practice. MariaDB Connector/J will set the SQLState (see java.sql.SQLException.getSQLState() in your API docs) to '08S01' when it encounters network-connectivity issues during the processing of a query. Attempt to reconnect to MariaDB at this point.

The following (simplistic) example shows what code that can handle these exceptions might look like:

Example 20.12. Connector/J: Example of transaction with retry logic

public void doBusinessOp() throws SQLException {
 Connection conn = null;
 Statement stmt = null;
 ResultSet rs = null;
 //
 // How many times do you want to retry the transaction
 // (or at least _getting_ a connection)?
 //
 int retryCount = 5;
 boolean transactionCompleted = false;
 do {
 try {
 conn = getConnection(); // assume getting this from a
 // javax.sql.DataSource, or the
 // java.sql.DriverManager
 conn.setAutoCommit(false);
 //
 // Okay, at this point, the 'retry-ability' of the
 // transaction really depends on your application logic,
 // whether or not you're using autocommit (in this case
 // not), and whether you're using transactional storage
 // engines
 //
 // For this example, we'll assume that it's _not_ safe
 // to retry the entire transaction, so we set retry
 // count to 0 at this point
 //
 // If you were using exclusively transaction-safe tables,
 // or your application could recover from a connection going
 // bad in the middle of an operation, then you would not
 // touch 'retryCount' here, and just let the loop repeat
 // until retryCount == 0.
 //
 retryCount = 0;
 stmt = conn.createStatement();
 String query = 'SELECT foo FROM bar ORDER BY baz';
 rs = stmt.executeQuery(query);
 while (rs.next()) {
 }
 rs.close();
 rs = null;
 stmt.close();
 stmt = null;
 conn.commit();
 conn.close();
 conn = null;
 transactionCompleted = true;
 } catch (SQLException sqlEx) {
 //
 // The two SQL states that are 'retry-able' are 08S01
 // for a communications error, and 40001 for deadlock.
 //
 // Only retry if the error was due to a stale connection,
 // communications problem or deadlock
 //
 String sqlState = sqlEx.getSQLState();
 if ('08S01'.equals(sqlState) || '40001'.equals(sqlState)) {
 retryCount--;
 } else {
 retryCount = 0;
 }
 } finally {
 if (rs != null) {
 try {
 rs.close();
 } catch (SQLException sqlEx) {
 // You'd probably want to log this . . .
 }
 }
 if (stmt != null) {
 try {
 stmt.close();
 } catch (SQLException sqlEx) {
 // You'd probably want to log this as well . . .
 }
 }
 if (conn != null) {
 try {
 //
 // If we got here, and conn is not null, the
 // transaction should be rolled back, as not
 // all work has been done
 try {
 conn.rollback();
 } finally {
 conn.close();
 }
 } catch (SQLException sqlEx) {
 //
 // If we got an exception here, something
 // pretty serious is going on, so we better
 // pass it up the stack, rather than just
 // logging it. . .
 throw sqlEx;
 }
 }
 }
 } while (!transactionCompleted && (retryCount > 0));
}
Note

Use of the autoReconnect option is not recommended because there is no safe method of reconnecting to the MariaDB server without risking some corruption of the connection state or database state information. Instead, use a connection pool, which will enable your application to connect to the MariaDB server using an available connection from the pool. The autoReconnect facility is deprecated, and may be removed in a future release.

21.3.12.5: I'm trying to use JDBC-2.0 updatable result sets, and I get an exception saying my result set is not updatable.

Because MariaDB does not have row identifiers, MariaDB Connector/J can only update result sets that have come from queries on tables that have at least one primary key, the query must select every primary key and the query can only span one table (that is, no joins). This is outlined in the JDBC specification.

Note that this issue only occurs when using updatable result sets, and is caused because Connector/J is unable to guarantee that it can identify the correct rows within the result set to be updated without having a unique reference to each row. There is no requirement to have a unique field on a table if you are using UPDATE or DELETE statements on a table where you can individually specify the criteria to be matched using a WHERE clause.

21.3.12.6: I cannot connect to the MariaDB server using Connector/J, and I'm sure the connection parameters are correct.

Make sure that the skip-networking option has not been enabled on your server. Connector/J must be able to communicate with your server over TCP/IP, named sockets are not supported. Also ensure that you are not filtering connections through a Firewall or other network security system. For more information, see "Can't connect to [local] MariaDB server".

21.3.12.7: I am trying to connect to my MariaDB server within my application, but I get the following error and stack trace: 

java.net.SocketException MESSAGE: Software caused connection abort: recv failed STACKTRACE:
java.net.SocketException: Software caused connection abort: recv failed at java.net.SocketInputStream.socketRead0(Native Method)
at java.net.SocketInputStream.read(Unknown Source)
at com.mysql.jdbc.MysqlIO.readFully(MysqlIO.java:1392)
at com.mysql.jdbc.MysqlIO.readPacket(MysqlIO.java:1414)
at com.mysql.jdbc.MysqlIO.doHandshake(MysqlIO.java:625)
at com.mysql.jdbc.Connection.createNewIO(Connection.java:1926)
at com.mysql.jdbc.Connection.<init>(Connection.java:452)
at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:411)

The error probably indicates that you are using a older version of the Connector/J JDBC driver (2.0.14 or 3.0.x) and you are trying to connect to a MariaDB server with version 4.1x or newer. The older drivers are not compatible with 4.1 or newer of MariaDB as they do not support the newer authentication mechanisms.

It is likely that the older version of the Connector/J driver exists within your application directory or your CLASSPATH includes the older Connector/J package.

21.3.12.8: My application is deployed through JBoss and I am using transactions to handle the statements on the MariaDB database. Under heavy loads I am getting a error and stack trace, but these only occur after a fixed period of heavy activity.

This is a JBoss, not Connector/J, issue and is connected to the use of transactions. Under heavy loads the time taken for transactions to complete can increase, and the error is caused because you have exceeded the predefined timeout.

You can increase the timeout value by setting the TransactionTimeout attribute to the TransactionManagerService within the /conf/jboss-service.xml file (pre-4.0.3) or /deploy/jta-service.xml for JBoss 4.0.3 or later. See TransactionTimeoute within the JBoss wiki for more information.

21.3.12.9: When using gcj an java.io.CharConversionException is raised when working with certain character sequences.

This is a known issue with gcj which raises an exception when it reaches an unknown character or one it cannot convert. Add useJvmCharsetConverters=true to your connection string to force character conversion outside of the gcj libraries, or try a different JDK.

21.3.12.10: Updating a table that contains a primary key that is either FLOAT or compound primary key that uses FLOAT fails to update the table and raises an exception.

Connector/J adds conditions to the WHERE clause during an UPDATE to check the old values of the primary key. If there is no match then Connector/J considers this a failure condition and raises an exception.

The problem is that rounding differences between supplied values and the values stored in the database may mean that the values never match, and hence the update fails. The issue will affect all queries, not just those from Connector/J.

To prevent this issue, use a primary key that does not use FLOAT. If you have to use a floating point column in your primary key use DOUBLE or DECIMAL types in place of FLOAT.

21.3.12.11: You get an ER_NET_PACKET_TOO_LARGE exception, even though the binary blob size you want to insert using JDBC is safely below the max_allowed_packet size.

This is because the hexEscapeBlock() method in com.mysql.jdbc.PreparedStatement.streamToBytes() may almost double the size of your data.

21.3.12.12: What should you do if you receive error messages similar to the following: "Communications link failure - Last packet sent to the server was X ms ago"?

Generally speaking, this error suggests that the network connection has been closed. There can be several root causes:

To help troubleshoot these issues, the following tips can be used. If a recent (5.1.13+) version of Connector/J is used, you will see an improved level of information compared to earlier versions. Older versions simply display the last time a packet was sent to the server, which is frequently 0 ms ago. This is of limited use, as it may be that a packet was just sent, while a packet from the server has not been received for several hours. Knowing the period of time since Connector/J last received a packet from the server is useful information, so if this is not displayed in your exception message, it is recommended that you update Connector/J.

Further, if the time a packet was last sent/received exceeds the wait_timeout or interactive_timeout threshold, this is noted in the exception message.

Although network connections can be volatile, the following can be helpful in avoiding problems:

Note

Do not expect to be able to reuse a connection without problems, if it has being lying idle for a period. If a connection is to be reused after being idle for any length of time, ensure that you explicitly test it before reusing it.

21.3.12.13: Why does Connector/J not reconnect to MariaDB and re-issue the statement after a communication failure, instead of throwing an Exception, even though I use the autoReconnect connection string option?

There are several reasons for this. The first is transactional integrity. The MariaDB Reference Manual states that "there is no safe method of reconnecting to the MariaDB server without risking some corruption of the connection state or database state information". Consider the following series of statements for example: 

conn.createStatement().execute(
 'UPDATE checking_account SET balance = balance - 1000.00 WHERE customer="Smith"');
conn.createStatement().execute(
 'UPDATE savings_account SET balance = balance + 1000.00 WHERE customer="Smith"');
conn.commit();

Consider the case where the connection to the server fails after the UPDATE to checking_account. If no exception is thrown, and the application never learns about the problem, it will continue executing. However, the server did not commit the first transaction in this case, so that will get rolled back. But execution continues with the next transaction, and increases the savings_account balance by 1000. The application did not receive an exception, so it continued regardless, eventually committing the second transaction, as the commit only applies to the changes made in the new connection. Rather than a transfer taking place, a deposit was made in this example.

Note that running with auto-commit enabled does not solve this problem. When Connector/J encounters a communication problem, there is no means to determine whether the server processed the currently executing statement or not. The following theoretical states are equally possible:

If you are running with auto-commit enabled, it is not possible to guarantee the state of data on the server when a communication exception is encountered. The statement may have reached the server, or it may not. All you know is that communication failed at some point, before the client received confirmation (or data) from the server. This does not only affect auto-commit statements though. If the communication problem occurred during Connection.commit(), the question arises of whether the transaction was committed on the server before the communication failed, or whether the server received the commit request at all.

The second reason for the generation of exceptions is that transaction-scoped contextual data may be vulnerable, for example:

These items are lost when a connection fails, and if the connection silently reconnects without generating an exception, this could be detrimental to the correct execution of your application.

In summary, communication errors generate conditions that may well be unsafe for Connector/J to simply ignore by silently reconnecting. It is necessary for the application to be notified. It is then for the application developer to decide how to proceed in the event of connection errors and failures.

21.3.12.14: How can I use 3-byte UTF8 with Connector/J?

To use 3-byte UTF8 with Connector/J set characterEncoding=utf8 and set useUnicode=true in the connection string.

21.3.12.15: How can I use 4-byte UTF8, utf8mb4 with Connector/J?

To use 4-byte UTF8 with Connector/J configure the MariaDB server with character_set_server=utf8mb4. Connector/J will then use that setting as long as characterEncoding has not been set in the connection string. This is equivalent to autodetection of the character set.

21.3.12.16: Using useServerPrepStmts=false and certain character encodings can lead to corruption when inserting BLOBs. How can this be avoided?

When using certain character encodings, such as SJIS, CP932, and BIG5, it is possible that BLOB data contains characters that can be interpreted as control characters, for example, backslash, '\'. This can lead to corrupted data when inserting BLOBs into the database. There are two things that need to be done to avoid this:

  1. Set the connection string option useServerPrepStmts to true.
  2. Set SQL_MODE to NO_BACKSLASH_ESCAPES.

Connector/J Support

Connector/J Community Support
How to Report Connector/J Bugs or Problems
Connector/J Change History

Connector/J Community Support

Oracle provides assistance to the user community by means of its mailing lists. For Connector/J related issues, you can get help from experienced users by using the MariaDB and Java mailing list. Archives and subscription information is available online at http://lists.mysql.com/java.

For information about subscribing to MariaDB mailing lists or to browse list archives, visit http://lists.mysql.com/. See , "MySQL Mailing Lists".

Community support from experienced users is also available through the JDBC Forum. You may also find help from other users in the other MariaDB Forums, located at http://forums.mysql.com. See , "MySQL Community Support at the MariaDB Forums".

How to Report Connector/J Bugs or Problems

The normal place to report bugs is https://jira.mariadb.org/, which is the address for our bugs database. This database is public, and can be browsed and searched by anyone. If you log in to the system, you will also be able to enter new reports.

If you have found a sensitive security bug in MySQL, you can send email to <security@mysql.com>.

Writing a good bug report takes patience, but doing it right the first time saves time both for us and for yourself. A good bug report, containing a full test case for the bug, makes it very likely that we will fix the bug in the next release.

This section will help you write your report correctly so that you do not waste your time doing things that may not help us much or at all.

If you have a repeatable bug report, please report it to the bugs database at https://jira.mariadb.org/. Any bug that we are able to repeat has a high chance of being fixed in the next MariaDB release.

To report other problems, you can use one of the MariaDB mailing lists.

Remember that it is possible for us to respond to a message containing too much information, but not to one containing too little. People often omit facts because they think they know the cause of a problem and assume that some details do not matter.

A good principle is this: If you are in doubt about stating something, state it. It is faster and less troublesome to write a couple more lines in your report than to wait longer for the answer if we must ask you to provide information that was missing from the initial report.

The most common errors made in bug reports are (a) not including the version number of Connector/J or MariaDB used, and (b) not fully describing the platform on which Connector/J is installed (including the JVM version, and the platform type and version number that MariaDB itself is installed on).

This is highly relevant information, and in 99 cases out of 100, the bug report is useless without it. Very often we get questions like, "Why doesn't this work for me?" Then we find that the feature requested wasn't implemented in that MariaDB version, or that a bug described in a report has already been fixed in newer MariaDB versions.

Sometimes the error is platform-dependent; in such cases, it is next to impossible for us to fix anything without knowing the operating system and the version number of the platform.

If at all possible, create a repeatable, standalone testcase that doesn't involve any third-party classes.

To streamline this process, we ship a base class for testcases with Connector/J, named 'com.mysql.jdbc.util.BaseBugReport'. To create a testcase for Connector/J using this class, create your own class that inherits from com.mysql.jdbc.util.BaseBugReport and override the methods setUp(), tearDown() and runTest().

In the setUp() method, create code that creates your tables, and populates them with any data needed to demonstrate the bug.

In the runTest() method, create code that demonstrates the bug using the tables and data you created in the setUp method.

In the tearDown() method, drop any tables you created in the setUp() method.

In any of the above three methods, use one of the variants of the getConnection() method to create a JDBC connection to MySQL:

If you need to use a JDBC URL that is different from 'jdbc:mysql:///test', override the method getUrl() as well.

Use the assertTrue(boolean expression) and assertTrue(String failureMessage, boolean expression) methods to create conditions that must be met in your testcase demonstrating the behavior you are expecting (vs. the behavior you are observing, which is why you are most likely filing a bug report).

Finally, create a main() method that creates a new instance of your testcase, and calls the run method: 

public static void main(String[] args) throws Exception {
 new MyBugReport().run();
 }

Once you have finished your testcase, and have verified that it demonstrates the bug you are reporting, upload it with your bug report to https://jira.mariadb.org/.

Connector/J Change History

The Connector/J Change History (Changelog) is located with the main Changelog for MySQL. See "MySQL Connector/J Change History".

MySQL Connector/MXJ

Overview of Connector/MXJ
Connector/MXJ Versions
Connector/MXJ Installation
Connector/MXJ Configuration
Connector/MXJ Reference
Connector/MXJ Notes and Tips
Connector/MXJ Samples
Connector/MXJ Support

MySQL Connector/MXJ is a Java Utility package for deploying and managing a MariaDB database. Deploying and using MariaDB can be as easy as adding another parameter to the JDBC connection URL, which will result in the database being started when the first connection is made. This makes it easy for Java developers to deploy applications which require a database by reducing installation barriers for their end-users.

MySQL Connector/MXJ makes the MariaDB database appear to be a Java-based component. It does this by determining what platform the system is running on, selecting the appropriate binary, and launching the executable. It will also optionally deploy an initial database, with any specified parameters.

Included are instructions for use with a JDBC driver and deploying as a JMX MBean to JBoss.

You can download sources and binaries from: http://dev.mysql.com/downloads/connector/mxj/

This a beta release and feedback is welcome and encouraged.

Please send questions or comments to the MySQL and Java mailing list.

Overview of Connector/MXJ

Connector/MXJ consists of a Java class, a copy of the mysqld binary for a specific list of platforms, and associated files and support utilities. The Java class controls the initialization of an instance of the embedded mysqld binary, and the ongoing management of the mysqld process. The entire sequence and management can be controlled entirely from within Java using the Connector/MXJ Java classes. You can see an overview of the contents of the Connector/MXJ package in the figure below.Connector/MXJ Overview

It is important to note that Connector/MXJ is not an embedded version of MySQL, or a version of MariaDB written as part of a Java class. Connector/MXJ works through the use of an embedded, compiled binary of mysqld as would normally be used when deploying a standard MariaDB installation.

It is the Connector/MXJ wrapper, support classes and tools, that enable Connector/MXJ to appear as a MariaDB instance.

When Connector/MXJ is initialized, the corresponding mysqld binary for the current platform is extracted, along with a pre-configured data directed. Both are contained within the Connector/MXJ JAR file. The mysqld instance is then started, with any additional options as specified during the initialization, and the MariaDB database becomes accessible.

Because Connector/MXJ works in combination with Connector/J, you can access and integrate with the MariaDB instance through a JDBC connection. When you have finished with the server, the instance is terminated, and, by default, any data created during the session is retained within the temporary directory created when the instance was started.

Connector/MXJ and the embedded mysqld instance can be deployed in a number of environments where relying on an existing database, or installing a MariaDB instance would be impossible, including CD-ROM embedded database applications and temporary database requirements within a Java-based application environment.

Connector/MXJ Versions

Connector/MXJ 5.x, currently in beta status, includes mysqld version 5.x and includes binaries for Linux x86, Mac OS X PPC, Windows XP/NT/2000 x86 and Solaris SPARC. Connector/MXJ 5.x requires the Connector/J 5.x package.

A summary of the different MariaDB versions supplied with each Connector/MXJ release are shown in the table.

Connector/MXJ Version MySQL Version(s)
5.0.11 5.1.40
5.0.9 5.0.51a (CS), 5.0.54 (ES)
5.0.8 (CS), 5.0.46 (ES)
5.0.7 (CS), 5.0.42 (ES)
5.0.6 (CS), 5.0.40 (ES)
5.0.5 (CS), 5.0.36 (ES)
5.0.4 (CS), 5.0.32 (ES)
5.0.3 5.0.22
5.0.2 5.0.19

This guide provides information on the Connector/MXJ 5.x release. For information on using the older releases, please see the documentation included with the appropriate distribution.

Connector/MXJ Installation

Supported Platforms
Connector/MXJ Base Installation
Connector/MXJ Quick Start Guide
Deploying Connector/MXJ using Driver Launch
Deploying Connector/MXJ within JBoss
Verifying Installation using JUnit

Connector/MXJ does not have a installation application or process, but there are some steps you can follow to make the installation and deployment of Connector/MXJ easier.

Before you start, there are some baseline requirements for

Depending on your target installation/deployment environment you may also require:

Supported Platforms

Connector/MXJ is compatible with any platform supporting Java and MySQL. By default, Connector/MXJ incorporates the mysqld binary for a select number of platforms which differs by version. The following platforms have been tested and working as deployment platforms. Support for all the platforms listed below is not included by default.

The Connector/MXJ 5.0.8 release includes mysqld binaries for the following platforms:

For more information on packaging your own Connector/MXJ with the platforms you require, see , "Creating your own Connector/MXJ Package"

Connector/MXJ Base Installation

Because there is no formal installation process, the method, installation directory, and access methods you use for Connector/MXJ are entirely up to your individual requirements.

To perform a basic installation, choose a target directory for the files included in the Connector/MXJ package. On Unix/Linux systems, you might use a directory such as /usr/local/connector-mxj. On Windows, you might install the files in the base directory, C:\Connector-MXJ, or within the Program Files directory.

To install the files, for a Connector/MXJ 5.0.4 installation:

  1. Download the Connector/MXJ package, either in Tar/Gzip format (ideal for Unix/Linux systems) or Zip format (Windows).
  2. Extract the files from the package. This will create a directory mysql-connector-mxj-gpl-[ver]. Copy and optionally rename this directory to your desired location.
  3. For best results, update your global CLASSPATH variable with the location of the required jar files.

    Within Unix/Linux you can do this globally by editing the global shell profile, or on a user by user basis by editing their individual shell profile.

    On Windows 2000, Windows NT and Windows XP, you can edit the global CLASSPATH by editing the Environment Variables configured through the System control panel.

For Connector/MXJ 5.0.6 and later you need the following JAR files in your CLASSPATH:

For Connector/MXJ 5.0.4 and later you need the following JAR files in your CLASSPATH:

For Connector/MXJ 5.0.3 and earlier, you need the following JAR files:

Connector/MXJ Quick Start Guide

Once you have extracted the Connector/MXJ and Connector/J components you can run one of the sample applications that initiates a MariaDB instance. You can test the installation by running the ConnectorMXJUrlTestExample: 

shell> java ConnectorMXJUrlTestExample jdbc:mysql:mxj://localhost:3336/our_test_app?server.basedir»
 =/var/tmp/test-mxj&createDatabaseIfNotExist=true&server.initialize-user=true
[/var/tmp/test-mxj/bin/mysqld][--no-defaults][--port=3336][--socket=mysql.sock]»
 [--basedir=/var/tmp/test-mxj][--datadir=/var/tmp/test-mxj/data]»
 [--pid-file=/var/tmp/test-mxj/data/MysqldResource.pid]
[MysqldResource] launching mysqld (driver_launched_mysqld_1)
InnoDB: The first specified data file ./ibdata1 did not exist:
InnoDB: a new database to be created!
080220 9:40:20 InnoDB: Setting file ./ibdata1 size to 10 MB InnoDB: Database physically writes the file full: wait...
080220 9:40:20 InnoDB: Log file ./ib_logfile0 did not exist: new to be created InnoDB: Setting log file ./ib_logfile0 size to 5 MB InnoDB: Database physically writes the file full: wait...
080220 9:40:20 InnoDB: Log file ./ib_logfile1 did not exist: new to be created InnoDB: Setting log file ./ib_logfile1 size to 5 MB InnoDB: Database physically writes the file full: wait...
InnoDB: Doublewrite buffer not found: creating new InnoDB: Doublewrite buffer created InnoDB: Creating foreign key constraint system tables InnoDB: Foreign key constraint system tables created
080220 9:40:21 InnoDB: Started; log sequence number 0 0
080220 9:40:21 [Note] /var/tmp/test-mxj/bin/mysqld: ready for connections.
Version: '5.0.51a' socket: 'mysql.sock' port: 3336 MariaDB Community Server (GPL)
[MysqldResource] mysqld running as process: 2238
------------------------
SELECT VERSION()
------------------------
5.0.51a
------------------------
[MysqldResource] stopping mysqld (process: 2238)
080220 9:40:27 [Note] /var/tmp/test-mxj/bin/mysqld: Normal shutdown
080220 9:40:27 InnoDB: Starting shutdown...
080220 9:40:29 InnoDB: Shutdown completed; log sequence number 0 43655
080220 9:40:29 [Note] /var/tmp/test-mxj/bin/mysqld: Shutdown complete
[MysqldResource] shutdown complete

The above output shows an instance of MariaDB starting, the necessary files being created (log files, InnoDB data files) and the MariaDB database entering the running state. The instance is then shutdown by Connector/MXJ before the example terminates.Warning

Avoid running your Connector/MXJ application as the root user, because this will cause the mysqld to also be executed with root privileges. For more information, see , "How to Run MariaDB as a Normal User".

Deploying Connector/MXJ using Driver Launch

Connector/MXJ and Connector/J work together to enable you to launch an instance of the mysqld server through the use of a keyword in the JDBC connection string. Deploying Connector/MXJ within a Java application can be automated through this method, making the deployment of Connector/MXJ a simple process:

  1. Download and unzip Connector/MXJ. Add mysql-connector-mxj-gpl-[ver].jar to the CLASSPATH.

    If you are using Connector/MXJ v5.0.4 or later, also add the mysql-connector-mxj-gpl-[ver]-db-files.jar file to your CLASSPATH.

  2. To the JDBC connection string, embed the mxj keyword, for example: jdbc:mysql:mxj://localhost:PORT/DBNAME.

For more details, see , "Connector/MXJ Configuration".

Deploying Connector/MXJ within JBoss

For deployment of Connector/MXJ within a JBoss environment, you must configure the JBoss environment to use the Connector/MXJ component within the JDBC parameters:

  1. Download Connector/MXJ and copy the mysql-connector-mxj-gpl-[ver].jar file to the $JBOSS_HOME/server/default/lib directory.

    If you are using Connector/MXJ v5.0.4 or later, also copy the mysql-connector-mxj-gpl-[ver]-db-files.jar file to $JBOSS_HOME/server/default/lib.

  2. Download Connector/J and copy the mysql-connector-java-5.1.5-bin.jar file to the $JBOSS_HOME/server/default/lib directory.
  3. Create an MBean service xml file in the $JBOSS_HOME/server/default/deploy directory with any attributes set, for instance the datadir and autostart.
  4. Set the JDBC parameters of your web application to use: 
    String driver = 'com.mysql.jdbc.Driver';
String url = 'jdbc:mysql:///test?propertiesTransform='+
 'com.mysql.management.jmx.ConnectorMXJPropertiesTransform';
String user = 'root';
String password = '';
Class.forName(driver);
Connection conn = DriverManager.getConnection(url, user, password);

You might create a separate users and database table spaces for each application, rather than using 'root and test'.

We highly suggest having a routine backup procedure for backing up the database files in the datadir.

Verifying Installation using JUnit

JUnit Test Requirements
Running the JUnit Tests

The best way to ensure that your platform is supported is to run the JUnit tests. These will test the Connector/MXJ classes and the associated components.

JUnit Test Requirements

The first thing to do is make sure that the components will work on the platform. The MysqldResource class is really a wrapper for a native version of MySQL, so not all platforms are supported. At the time of this writing, Linux on the i386 architecture has been tested and seems to work quite well, as does OS X v10.3. There has been limited testing on Windows and Solaris.

Requirements:

  1. JDK-1.4 or newer (or the JRE if you aren't going to be compiling the source or JSPs).
  2. MySQL Connector/J version 5.0 or newer (from http://dev.mysql.com/downloads/connector/j/) installed and available using your CLASSPATH.
  3. The javax.management classes for JMX version 1.2.1, these are present in the following application servers:
  4. JUnit 3.8.1 (from http://www.junit.org/).

If building from source, All of the requirements from above, plus:

  1. Ant version 1.5 or newer (download from http://ant.apache.org/).
Running the JUnit Tests
  1. The tests attempt to launch MariaDB on the port 3336. That MariaDB instance is unlikely to conflict with another MariaDB server on the same machine, because the default port for MariaDB is 3306. If you do encounter a port conflict, either set the c-mxj_test_port Java property to a port of your choosing, or shut down any instances of MariaDB you have running on the target machine.

    The tests suppress output to the console by default. For verbose output, you may set the c-mxj_test_silent Java property to false.

  2. To run the JUnit test suite, the $CLASSPATH must include the following:
    • JUnit
    • JMX
    • Connector/J
    • MySQL Connector/MXJ
  3. If connector-mxj.jar is not present in your download, unzip MariaDB Connector/MXJ source archive. 
    cd mysqldjmx ant dist

    Then add $TEMP/cmxj/stage/connector-mxj/connector-mxj.jar to the CLASSPATH.

  4. If you have junit, execute the unit tests. From the command line, type: 
    java com.mysql.management.AllTestsSuite

    The output should look something like this: 

    .........................................
.........................................
..........
Time: 259.438
OK (101 tests)

    Note that the tests are a bit slow near the end, so please be patient.

Connector/MXJ Configuration

Running as part of the JDBC Driver
Running within a Java Object
Setting server options

Running as part of the JDBC Driver

A feature of the MariaDB Connector/J JDBC driver is the ability to specify a connection to an embedded Connector/MXJ instance through the use of the mxj keyword in the JDBC connection string.

In the following example, we have a program which creates a connection, executes a query, and prints the result to the System.out. The MariaDB database will be deployed and started as part of the connection process, and shutdown as part of the finally block.

You can find this file in the Connector/MXJ package as src/ConnectorMXJUrlTestExample.java. 

import java.io.File;
import java.sql.Connection;
import java.sql.DriverManager;
import com.mysql.management.driverlaunched.ServerLauncherSocketFactory;
import com.mysql.management.util.QueryUtil;
public class ConnectorMXJUrlTestExample {
 public static String DRIVER = 'com.mysql.jdbc.Driver';
 public static String JAVA_IO_TMPDIR = 'java.io.tmpdir';
 public static void main(String[] args) throws Exception {
 File ourAppDir = new File(System.getProperty(JAVA_IO_TMPDIR));
 File databaseDir = new File(ourAppDir, 'test-mxj');
 int port = Integer.parseInt(System.getProperty('c-mxj_test_port', '3336'));
 String dbName = 'our_test_app';
 String url = 'jdbc:mysql:mxj://localhost:' + port + '/' + dbName //
 + '?' + 'server.basedir=' + databaseDir //
 + '&' + 'createDatabaseIfNotExist=true'//
 + '&' + 'server.initialize-user=true' //
 ;
 System.out.println(url);
 String userName = 'alice';
 String password = 'q93uti0opwhkd';
 Class.forName(DRIVER);
 Connection conn = null;
 try {
 conn = DriverManager.getConnection(url, userName, password);
 String sql = 'SELECT VERSION()';
 String queryForString = new QueryUtil(conn).queryForString(sql);
 System.out.println('------------------------');
 System.out.println(sql);
 System.out.println('------------------------');
 System.out.println(queryForString);
 System.out.println('------------------------');
 System.out.flush();
 Thread.sleep(100); // wait for System.out to finish flush
 } finally {
 try {
 if (conn != null)
 conn.close();
 } catch (Exception e) {
 e.printStackTrace();
 }
 ServerLauncherSocketFactory.shutdown(databaseDir, null);
 }
 }
}

To run the above program, be sure to have connector-mxj.jar and Connector/J in the CLASSPATH. Then type: 

java ConnectorMXJUrlTestExample

Running within a Java Object

To "embed" a MariaDB database within a Java application, use the com.mysql.management.MysqldResource class directly. This class may be instantiated with the default (no argument) constructor, or by passing in a java.io.File object representing the directory into which to unzip the server. It may also be instantiated with printstreams for stdout and stderr for logging.

Once instantiated, a java.util.Map, the object will be able to provide a java.util.Map of server options appropriate for the platform and version of MariaDB which you will be using.

The MysqldResource enables you to 'start' MariaDB with a java.util.Map of server options which you provide, as well as 'shutdown' the database. The following example shows a simplistic way to embed MariaDB in an application using plain java objects.

You can find this file in the Connector/MXJ package as src/ConnectorMXJObjectTestExample.java. 

import java.io.File;
import java.sql.Connection;
import java.sql.DriverManager;
import java.util.HashMap;
import java.util.Map;
import com.mysql.management.MysqldResource;
import com.mysql.management.MysqldResourceI;
import com.mysql.management.util.QueryUtil;
public class ConnectorMXJObjectTestExample {
 public static final String DRIVER = 'com.mysql.jdbc.Driver';
 public static final String JAVA_IO_TMPDIR = 'java.io.tmpdir';
 public static void main(String[] args) throws Exception {
 File ourAppDir = new File(System.getProperty(JAVA_IO_TMPDIR));
 File databaseDir = new File(ourAppDir, 'mysql-mxj');
 int port = Integer.parseInt(System.getProperty('c-mxj_test_port',
 '3336'));
 String userName = 'alice';
 String password = 'q93uti0opwhkd';
 MysqldResource mysqldResource = startDatabase(databaseDir, port,
 userName, password);
 Class.forName(DRIVER);
 Connection conn = null;
 try {
 String dbName = 'our_test_app';
 String url = 'jdbc:mysql://localhost:' + port + '/' + dbName //
 + '?' + 'createDatabaseIfNotExist=true'//
 ;
 conn = DriverManager.getConnection(url, userName, password);
 String sql = 'SELECT VERSION()';
 String queryForString = new QueryUtil(conn).queryForString(sql);
 System.out.println('------------------------');
 System.out.println(sql);
 System.out.println('------------------------');
 System.out.println(queryForString);
 System.out.println('------------------------');
 System.out.flush();
 Thread.sleep(100); // wait for System.out to finish flush
 } finally {
 try {
 if (conn != null) {
 conn.close();
 }
 } catch (Exception e) {
 e.printStackTrace();
 }
 try {
 mysqldResource.shutdown();
 } catch (Exception e) {
 e.printStackTrace();
 }
 }
 }
 public static MysqldResource startDatabase(File databaseDir, int port,
 String userName, String password) {
 MysqldResource mysqldResource = new MysqldResource(databaseDir);
 Map database_options = new HashMap();
 database_options.put(MysqldResourceI.PORT, Integer.toString(port));
 database_options.put(MysqldResourceI.INITIALIZE_USER, 'true');
 database_options.put(MysqldResourceI.INITIALIZE_USER_NAME, userName);
 database_options.put(MysqldResourceI.INITIALIZE_PASSWORD, password);
 mysqldResource.start('test-mysqld-thread', database_options);
 if (!mysqldResource.isRunning()) {
 throw new RuntimeException('MySQL did not start.');
 }
 System.out.println('MySQL is running.');
 return mysqldResource;
 }
}

Setting server options

There are many options you might set for a MariaDB database. These options may be specified as part of the JDBC connection string simply by prefixing each server option with server.. The following example sets two driver parameters and two server parameters: 

 String url = 'jdbc:mysql://' + hostColonPort + '/'
 + '?'
 + 'cacheServerConfiguration=true'
 + '&'
 + 'useLocalSessionState=true'
 + '&'
 + 'server.basedir=/opt/myapp/db'
 + '&'
 + 'server.datadir=/mnt/bigdisk/myapp/data';

Starting with Connector/MXJ 5.0.6, you can use the initialize-user property to a connection string. If set to true, the default anonymous and root users will be removed and the user/password combination from the connection URL will be used to create a new user. For example: 

 String url = 'jdbc:mysql:mxj://localhost:' + port
 + '/alice_db'
 + '?server.datadir=' + dataDir.getPath()
 + '&server.initialize-user=true'
 + '&createDatabaseIfNotExist=true'
 ;

Connector/MXJ Reference

MysqldResource Constructors
MysqldResource Methods

The following sections include detailed information on the different API interfaces to Connector/MXJ.

MysqldResource Constructors

The MysqldResource class supports three different constructor forms:

MysqldResource Methods

MysqldResource API includes the following methods:

Connector/MXJ Notes and Tips

Creating your own Connector/MXJ Package
Deploying Connector/MXJ with a pre-configured database
Running within a JMX Agent (custom)
Deployment in a standard JMX Agent environment (JBoss)

This section contains notes and tips on using the Connector/MXJ component within your applications.

Creating your own Connector/MXJ Package

To create a custom Connector/MXJ package that includes a specific mysqld version or platform, extract and rebuild the mysql-connector-mxj.jar (Connector/MXJ v5.0.3 or earlier) or mysql-connector-mxj-gpl-[ver]-db-files.jar (Connector/MXJ v5.0.4 or later) file.

First, create a new directory into which you can extract the current connector-mxj.jar: 

shell> mkdir custom-mxj shell> cd custom-mxj shell> jar -xf connector-mxj.jar shell> ls
5-0-22/
ConnectorMXJObjectTestExample.class ConnectorMXJUrlTestExample.class META-INF/
TestDb.class com/
kill.exe

If you are using Connector/MXJ v5.0.4 or later, unpack the connector-mxj-db-files.jar: 

shell> mkdir custom-mxj shell> cd custom-mxj shell> jar -xf connector-mxj-db-files.jar shell> ls
5-0-51a/
META-INF/
connector-mxj.properties

The MariaDB version directory, 5-0-22 or 5-0-51a in the preceding examples, contains all of the files used to create an instance of MariaDB when Connector/MXJ is executed. All of the files in this directory are required for each version of MariaDB to embed. Note as well the format of the version number, which uses hyphens instead of periods to separate the version number components.

Within the version specific directory are the platform specific directories, and archives of the data and share directory required by MariaDB for the various platforms. For example, here is the listing for the default Connector/MXJ package: 

shell>> ls Linux-i386/
META-INF/
Mac_OS_X-ppc/
SunOS-sparc/
Win-x86/
com/
data_dir.jar share_dir.jar win_share_dir.jar

Platform specific directories are listed by their OS and platform - for example the mysqld for Mac OS X PowerPC is located within the Mac_OS_X-ppc directory. You can delete directories from this location that you do not require, and add new directories for additional platforms that you intend to support.

To add a platform specific mysqld, create a new directory with the corresponding name for your operating system/platform. For example, you could add a directory for Mac OS X/Intel using the directory Mac_OS_X-i386.

On Unix systems, you can determine the platform using uname: 

shell> uname -p i386

In Connector/MXJ v5.0.9 and later, an additional platform-map.properties file is used to associate a specific platform and operating system combination with the directory in which the mysqld for that combination is located. The determined operating system and platform are on the left, and the directory name where the appropriate mysqld is located is on the right. You can see a sample of the file below: 

Linux-i386=Linux-i386
Linux-x86=Linux-i386
Linux-i686=Linux-i386
Linux-x86_64=Linux-i386
Linux-ia64=Linux-i386
#Linux-ppc=Linux-ppc
#Linux-ppc64=Linux-ppc Mac_OS_X-i386=Mac_OS_X-i386
Mac_OS_X-ppc=Mac_OS_X-ppc Rhapsody-PowerPC=Mac_OS_X-ppc
#Mac_OS-PowerPC=
#macos-PowerPC=
#MacOS-PowerPC=
SunOS-sparc=SunOS-sparc Solaris-sparc=SunOS-sparc SunOS-x86=SunOS-x86
Solaris-x86=SunOS-x86
FreeBSD-x86=FreeBSD-x86
Windows_Vista-x86=Win-x86
Windows_2003-x86=Win-x86
Windows_XP-x86=Win-x86
Windows_2000-x86=Win-x86
Windows_NT-x86=Win-x86
Windows_NT_(unknown)-x86=Win-x86

Now download or compile mysqld for the MariaDB version and platform you want to include in your custom connector-mxj.jar package into the new directory.

Create a file called version.txt in the OS/platform directory you have just created that contains the version string/path of the mysqld binary. For example: 

mysql-5.0.22-osx10.3-i386/bin/mysqld

You can now recreate the connector-mxj.jar file with the added mysqld: 

shell> cd custom-mxj shell> jar -cf ../connector-mxj.jar *

For Connector/MXJ v5.0.4 and later, repackage to the connector-mxj-db-files.jar: 

shell> cd custom-mxj shell> jar -cf ../mysql-connector-mxj-gpl-[ver]-db-files.jar *

Test this package using the steps outlined in , "Connector/MXJ Quick Start Guide".Note

Because the mysql-connector-mxj-gpl-[ver]-db-files.jar file is separate from the main Connector/MXJ classes you can distribute different mysql-connector-mxj-gpl-[ver]-db-files.jar files to different hosts or for different projects without having to create a completely new main mysql-connector-mxj-gpl-[ver].jar file for each one.

Deploying Connector/MXJ with a pre-configured database

To include a pre-configured/populated database within your Connector/MXJ JAR file you must create a custom data_dir.jar file, as included within the main connector-mxj.jar (Connector/MXJ 5.0.3 or earlier) or mysql-connector-mxj-gpl-[ver]-db-files.jar (Connector/MXJ 5.0.4 or later) file:

  1. First extract the connector-mxj.jar or mysql-connector-gpl-[ver]-db-files.jar file, as outlined in the previous section (see , "Creating your own Connector/MXJ Package").
  2. First, create your database and populate the database with the information you require in an existing instance of MariaDB - including Connector/MXJ instances. Data file formats are compatible across platforms.
  3. Shutdown the instance of MySQL.
  4. Create a JAR file of the data directory and databases that you intend to include your Connector/MXJ package. Include the MariaDB database, which includes user authentication information, in addition to the specific databases to include. For example, to create a JAR of the MariaDB and mxjtest databases: 
    shell> jar -cf ../data_dir.jar mysql mxjtest
  5. For Connector/MXJ 5.0.3 or earlier, copy the data_dir.jar file into the extracted connector-mxj.jar directory, and then create an archive for connector-mxj.jar.

    For Connector/MXJ 5.0.4 or later, copy the data_dir.jar file into the extracted mysql-connector-mxj-gpl-[ver]-db-files.jar directory, and then create an archive for mysql-connector-mxj-db-gpl-[ver]--files.jar.

Note that if you are create databases using the InnoDB engine, you must include the ibdata.* and ib_logfile* files within the data_dir.jar archive.

Running within a JMX Agent (custom)

As a JMX MBean, MariaDB Connector/MXJ requires a JMX v1.2 compliant MBean container, such as JBoss version 4. The MBean will uses the standard JMX management APIs to present (and allow the setting of) parameters which are appropriate for that platform.

If you are not using the SUN Reference implementation of the JMX libraries, skip this section. Or, if you are deploying to JBoss, you can also skip to the next section.

We want to see the MysqldDynamicMBean in action inside of a JMX agent. In the com.mysql.management.jmx.sunri package is a custom JMX agent with two MBeans:

  1. The MysqldDynamicMBean, and
  2. A com.sun.jdmk.comm.HtmlAdaptorServer, which provides a web interface for manipulating the beans inside of a JMX agent.

When this very simple agent is started, it will allow a MariaDB database to be started and stopped with a web browser.

  1. Complete the testing of the platform as above.

    • Current JDK, JUnit, Connector/J, MariaDB Connector/MXJ
    • This section requires the SUN reference implementation of JMX
    • PATH, JAVA_HOME, ANT_HOME, CLASSPATH
  2. If not building from source, skip to next step

    Rebuild with the 'sunri.present' 

    ant -Dsunri.present=true dist re-run tests:
java junit.textui.TestRunner com.mysql.management.AllTestsSuite
  3. Launch the test agent from the command line: 
    java com.mysql.management.jmx.sunri.MysqldTestAgentSunHtmlAdaptor &
  4. From a browser: 
    http://localhost:9092/
  5. Under MysqldAgent, 
    select 'name=mysqld'
  6. Observe the MBean View
  7. Scroll to the bottom of the screen press the startMysqld button
  8. Click Back to MBean View
  9. Scroll to the bottom of the screen press stopMysqld button
  10. Kill the java process running the Test Agent (jmx server)

Deployment in a standard JMX Agent environment (JBoss)

Once there is confidence that the MBean will function on the platform, deploying the MBean inside of a standard JMX Agent is the next step. Included are instructions for deploying to JBoss.

  1. Ensure a current version of java development kit (v1.4.x), see above.

    • Ensure JAVA_HOME is set (JBoss requires JAVA_HOME)
    • Ensure JAVA_HOME/bin is in the PATH (You will NOT need to set your CLASSPATH, nor will you need any of the jars used in the previous tests).
  2. Ensure a current version of JBoss (v4.0RC1 or better) 
    http://www.jboss.org/index.html select 'Downloads'
select 'jboss-4.0.zip'
pick a mirror unzip ~/dload/jboss-4.0.zip create a JBOSS_HOME environment variable set to the unzipped directory unix only:
cd $JBOSS_HOME/bin chmod +x *.sh
  3. Deploy (copy) the connector-mxj.jar to $JBOSS_HOME/server/default/lib.
  4. Deploy (copy) mysql-connector-java-3.1.4-beta-bin.jar to $JBOSS_HOME/server/default/lib.
  5. Create a mxjtest.war directory in $JBOSS_HOME/server/default/deploy.
  6. Deploy (copy) index.jsp to $JBOSS_HOME/server/default/deploy/mxjtest.war.
  7. Create a mysqld-service.xml file in $JBOSS_HOME/server/default/deploy. 
    <?xml version="1.0" encoding="UTF-8"?>
 <server>
 <mbean code="com.mysql.management.jmx.jboss.JBossMysqldDynamicMBean"
 name="mysql:type=service,name=mysqld">
 <attribute name="datadir">/tmp/xxx_data_xxx</attribute>
 <attribute name="autostart">true</attribute>
 </mbean>
 </server>
  8. Start jboss:
    • On unix: $JBOSS_HOME/bin/run.sh
    • On windows: %JBOSS_HOME%\bin\run.bat

    Be ready: JBoss sends a lot of output to the screen.

  9. When JBoss seems to have stopped sending output to the screen, open a web browser to: http://localhost:8080/jmx-console
  10. Scroll down to the bottom of the page in the MariaDB section, select the bulleted mysqld link.
  11. Observe the JMX MBean View page. MariaDB should already be running.
  12. (If 'autostart=true' was set, you may skip this step.) Scroll to the bottom of the screen. You may press the Invoke button to stop (or start) MariaDB observe Operation completed successfully without a return value. Click Back to MBean View
  13. To confirm MariaDB is running, open a web browser to http://localhost:8080/mxjtest/ and you should see that the following query: 
    SELECT 1

    returned with the following result: 

    1
  14. Guided by the $JBOSS_HOME/server/default/deploy/mxjtest.war/index.jsp you will be able to use MariaDB in your Web Application. There is a test database and a root user (no password) ready to experiment with. Try creating a table, inserting some rows, and doing some selects.
  15. Shut down MySQL. MariaDB will be stopped automatically when JBoss is stopped, or: from the browser, scroll down to the bottom of the MBean View press the stop service Invoke button to halt the service. Observe Operation completed successfully without a return value. Using ps or task manager see that MariaDB is no longer running

As of 1.0.6-beta version is the ability to have the MBean start the MariaDB database upon start up. Also, we've taken advantage of the JBoss life-cycle extension methods so that the database will gracefully shut down when JBoss is shutdown.

Connector/MXJ Samples

Using Connector/MXJ with JSP

This section contains some sample applications using Connector/MXJ.

Using Connector/MXJ with JSP

The following web application was provided by Pavan Venkatesh as an example of a JSP based application using Connector/MXJ to provide contact data. The example consists of two components, insertdata.jsp and response.jsp. The insertdata.jsp provides a form into which you can enter information to be stored within the MariaDB database provided by Connector/MXJ. The response.jsp file is called when you submit the form and then provides a table of the data.

Because the data is stored through Connector/MXJ the instantiation of the MariaDB database is handled dynamically on the fly, making the script lightweight and self-contained.

Example 20.13. insertdata.jsp 

<%@page contentType="text/html" pageEncoding="UTF-8"%>
<!DOCTYPE HTML PUBLIC '-//W3C//DTD HTML 4.01 Transitional//EN'
 'http://www.w3.org/TR/html4/loose.dtd'>
<%@ page import="java.sql.*"%>
<%@ page import="java.io.*"%>
<%@ page import="java.io.*"%>
<%@ page import="java.sql.*"%>
<HTML>
<HEAD>
<TITLE>insert data</TITLE>
<script language="Javascript">
function validFields(){
if (document.form2.ID.value == '' || document.form2.ID.value == null){
alert ( 'Please enter ID / Field cannot be left blank' );
return false;
}
if (document.form2.names.value == '' || document.form2.names.value == null){
alert ( 'Please enter Name / Field cannot be left blank' );
return false;
}
if (document.form2.place.value == ''|| document.form2.place.value == null){
alert ( 'Please enter Place / Field cannot be left blank' );
return false;
}
if (document.form2.phone.value == ''|| document.form2.phone.value == null){
alert ( 'Please enter Phone number / Field cannot be left blank' );
return false;
}
return true;
}
</script>
</HEAD>
<BODY >
<H1>Welcome to MariaDB world</H1>
<H2>MySQL with MXJ Connection</H2>
<P>Insert data in existing 'contactdetails2009' table under
'Directory' database</P>
<FORM action="response.jsp" method="get" name="form2">
<TABLE >
 <TR>
 <TH>
 <center>ID</center>
 </TH>
 <TD><INPUT TYPE="text" NAME="ID"></TD>
 </TR>
 <TR>
 <TH>
 <center>Name</center>
 </TH>
 <TD><INPUT TYPE="text" NAME="names"></TD>
 </TR>
 <TR>
 <TH>
 <center>City</center>
 </TH>
 <TD><INPUT TYPE="text" NAME="place"></TD>
 </TR>
 <TR>
 <TH>
 <center>Phone</center>
 </TH>
 <TD><INPUT TYPE="text" NAME="phone"></TD>
 </TR>
 <TR>
 <TH></TH>
 <TD><INPUT TYPE="submit" VALUE="Insert"
 ></TD>
 </TR>
</TABLE>
</FORM>
</BODY>

Example 20.14. response.jsp 

<%@ page import="java.sql.*"%>
<%@ page import="java.sql.*"%>
<%@ page import="java.io.*"%>
<%@ page import="java.io.*"%>
<%@ page import="java.sql.*"%>
<%@ page import="java.sql.Connection"%>
<%@ page import="java.sql.DriverManager"%>
<%@ page language="java"%>
<%@ page import=" com.mysql.management.util.QueryUtil"%>
<%@page contentType="text/html" pageEncoding="UTF-8"%>
<!DOCTYPE HTML PUBLIC '-//W3C//DTD HTML 4.01 Transitional//EN'
 'http://www.w3.org/TR/html4/loose.dtd'>
<HTML>
<HEAD>
<META http-equiv='Content-Type' content="text/html; charset=UTF-8">
<TITLE>JSP Page</TITLE>
</HEAD>
<BODY >
<P><INPUT type=button value="Back" ></P>
<H1>Welcome to Directory Database</H1>
<% 
 String ID = request.getParameter('ID');
 String name = request.getParameter('names');
 String city = request.getParameter('place');
 String phone = request.getParameter('phone');
 File ourAppDir1 = new File('/tmp/src');
 File databaseDir1 = new File(ourAppDir1,'database');
 int port = 4336;
 String dbName = 'Directory';
 try
 {
 String url = 'jdbc:mysql:mxj://localhost:' + port + '/' + dbName //
 + '?' + 'server.basedir=' + databaseDir1 //
 + '&' + 'createDatabaseIfNotExist=true'//
 + '&' + 'server.initialize-user=true' //
 ;
 Connection connection = null;
 int updateQuery=0;
 Class.forName('com.mysql.jdbc.Driver').newInstance();
 String userName = 'alice';
 String password = 'q93uti0opwhkd';
 connection = DriverManager.getConnection(url, userName, password);
 PreparedStatement pstatement = null;
 String sql = 'SELECT VERSION()';
 String queryForString = new QueryUtil(connection).queryForString(sql);
 String command = 'INSERT INTO contactdetails2009 (ID, name,city,phone) VALUES (?,?,?,?)';
 pstatement = connection.prepareStatement(command);
 pstatement.setString(1, ID);
 pstatement.setString(2, name);
 pstatement.setString(3, city);
 pstatement.setString(4, phone);
 updateQuery = pstatement.executeUpdate();
 ResultSet resultset = pstatement.executeQuery('select * from contactdetails2009');
 if (updateQuery != 0) { %>
<P>MySQL Version------------&gt; <% out.println(queryForString); %>
</P>
<TABLE >
 <TR>
 <TH >Data successfully inserted into
 MariaDB database using MXJ connection</TH>
 </TR>
 <TR>
 <th >Storage Engine used is MyISAM</th>
 </TR>
 <TR>
 <TD>
 <H2>ContactDetails2009 Table</H2>
 <TABLE >
 <TR>
 <TH>ID</TH>
 <TH>name</TH>
 <TH>city</TH>
 <TH>phone</TH>
 </TR>
 <%
 while(resultset.next()){ 
 %>
 <TR>
 <TD><%= resultset.getString(1) %></TD>
 <TD><%= resultset.getString(2) %></TD>
 <TD><%= resultset.getString(3) %></TD>
 <TD><%= resultset.getString(4) %></TD>
 </TR>
 <% 
 } %>
 <%
 resultset.close();
 pstatement.close();
 connection.close(); 
 }
 }
 catch (Exception e) {
 %>
 <TR>
 <TD>ERROR------------&gt; <%
 out.println('ID or Row already exist');
 }
 %>
 </TD>
 </TR>
 </TABLE>
 </TD>
 </TR>
</TABLE>
</BODY>
</HTML>

Connector/MXJ Support

Connector/MXJ Community Support
How to Report Connector/MXJ Problems
Connector/MXJ Change History

There are a wide variety of options available for obtaining support for using Connector/MXJ. Contact the Connector/MXJ community for help before reporting a potential bug or problem. See , "Connector/MXJ Community Support".

Connector/MXJ Community Support

Oracle provides assistance to the user community by means of a number of mailing lists and web based forums.

You can find help and support through the MySQL and Java mailing list.

For information about subscribing to MariaDB mailing lists or to browse list archives, visit http://lists.mysql.com/. See , "MySQL Mailing Lists".

Community support from experienced users is also available through the JDBC and Java forum. You may also find help from other users in the other MariaDB Forums, located at http://forums.mysql.com. See , "MySQL Community Support at the MariaDB Forums".

How to Report Connector/MXJ Problems

If you encounter difficulties or problems with Connector/MXJ, contact the Connector/MXJ community , "Connector/MXJ Community Support".

If reporting a problem, ideally include the following information with the email:

Remember that the more information you can supply to us, the more likely it is that we can fix the problem.

If you believe the problem to be a bug, then you must report the bug through https://jira.mariadb.org/.

Connector/MXJ Change History

The Connector/MXJ Change History (Changelog) is located with the main Changelog for MySQL. See "MySQL Connector/MXJ Change History".

MySQL Connector/C++

Installing the MariaDB Connector/C++ Binary
Installing MariaDB Connector/C++ from Source
MySQL Connector/C++ Building Windows Applications with Microsoft Visual Studio
MySQL Connector/C++ Building Linux Applications with NetBeans
MySQL Connector/C++ Getting Started: Usage Examples
MySQL Connector/C++ Tutorials
MySQL Connector/C++ Debug Tracing
MySQL Connector/C++ Usage Notes
MySQL Connector/C++ Known Bugs and Issues
MySQL Connector/C++ Feature requests
MySQL Connector/C++ Support
MySQL Connector/C++ FAQ

MySQL Connector/C++ is a MariaDB database connector for C++.

The MariaDB Connector/C++ is licensed under the terms of the GPL, like most MariaDB Connectors. There are special exceptions to the terms and conditions of the GPL as it is applied to this software, see FLOSS License Exception. If you need a non-GPL license for commercial distribution please contact us.

The MariaDB Connector/C++ is compatible with the JDBC 4.0 API. However, MariaDB Connector/C++ does not implement all of the JDBC 4.0 API. The MariaDB Connector/C++ current version features the following classes:

The JDBC 4.0 API defines approximately 450 methods for the above mentioned classes. MariaDB Connector/C++ implements around 80% of these and makes them available in the current release.

The release has been successfully compiled and tested on the following platforms:

AIX

FreeBSD

HPUX

Linux

Mac

SunOS

Windows

Future versions will run on all platforms supported by the MariaDB Server.Note

MySQL Connector/C++ supports MariaDB 5.1 and later.Note

MySQL Connector/C++ supports only Microsoft Visual Studio 2003 and above on Windows.

MySQL Connector/C++ Download

You can download the source code for the MariaDB Connector/C++ current release at the MySQL Connector/C++ downloads.

MySQL Connector/C++ Source repository

The latest development version is also available through Launchpad.

Bazaar is used for the MariaDB Connector/C++ code repository. You can check out the latest source code using the bzr command line tool: 

shell> bzr branch lp:~mysql/mysql-connector-cpp/trunk .

Binary distributions

Starting with 1.0.4 Beta, binary distributions were made available in addition to source code releases. The releases available are shown below.

Microsoft Windows platform:

Other platforms:

Note

Note that source packages are available for all platforms in the Compressed GNU TAR archive (tar.gz) format.

Binary and source packages can be obtained from MySQL Connector/C++ downloads.

MySQL Connector/C++ Advantages

Using MariaDB Connector/C++ instead of the MariaDB C API (MySQL Client Library) offers the following advantages for C++ users:

MySQL Connector/C++ Status

MySQL Connector/C++ is available as a GA version. We kindly ask users and developers to try it out and provide us with feedback.

Note that MariaDB Workbench is successfully using MariaDB Connector/C++.

If you have any queries please contact us.

Installing the MariaDB Connector/C++ Binary

Caution

One problem that can occur is when the tools you use to build your application are not compatible with the tools used to build the binary versions of MariaDB Connector/C++. Ideally, build your application with the same tools that were used to build the MariaDB Connector/C++ binaries. To help with this, the following resources are provided.

All distributions contain a README file, which contains platform-specific notes. At the end of the README file contained in the binary distribution you will find the settings used to build the binaries. If you experience build-related issues on a platform, it may help to check the settings used on the platform to build the binary.

Developers using Microsoft Windows must meet the following requirements:

  1. Use a supported version of Visual Studio, either Visual Studio 2005 or Visual Studio 2008.
  2. Ensure that your application uses the same run time library as that used to build MariaDB Connector/C++. Visual Studio 2005 builds use Microsoft.VC80.CRT (8.0.50727.762), and Visual Studio 2008 builds use Microsoft.VC90.CRT (9.0.21022.8).
  3. Your application should use the same linker configuration as MariaDB Connector/C++, for example use one of /MD, /MDd, /MT, or /MTd.

To use a variation of the requirements previously listed, such as a different compiler version, release configuration, or run time library, compile MariaDB Connector/C++ from source using your desired settings, and then ensure that your application is built with these same settings. Ensure that the three variables of compiler version, run time library, and run time linker configuration settings are the same for both application and MariaDB Connector/C++ itself, to avoid issues.

For your convenience the same information, but more frequently updated, can be found on the MySQL Forge site.

A better solution is to build your MariaDB Connector/C++ libraries from the source code, using the same tools that you use for building your application. This ensures compatibility.

Downloading MariaDB Connector/C++

Binary and source packages can be obtained from MySQL Connector/C++ downloads.

Archive Package

Unpack the archive into an appropriate directory. If you plan to use a dynamically linked version of MariaDB Connector/C++, make sure that your system can reference the MariaDB Client Library. Consult your operating system documentation on how do modify and expand the search path for libraries. In case you cannot modify the library search path it may help to copy your application, the MariaDB Connector/C++ library and the MariaDB Client Library into the same directory. Most systems search for libraries in the current directory.

Windows MSI Installer

Windows users can choose between two binary packages:

  1. Without installer (unzip in C:\)
  2. Windows MSI Installer (x86)

Using the MSI Installer may be the easiest solution. Running the MSI Installer does not require any administrative permissions as it simply copies files.

Figure 20.59. Windows Installer Welcome Screen

Windows Installer Welcome Screen

Figure 20.60. Windows Installer Overview Screen

Windows Installer Overview Screen

The "Typical" installation consists of all required header files and the Release libraries. The only available "Custom" installation option enables you to install additional Debug versions of the connector libraries.

Figure 20.61. Windows Installer Custom Setup Screen

Windows Installer Custom Setup Screen

Installing MariaDB Connector/C++ from Source

Building MariaDB Connector/C++ from Source on Unix, Solaris and Mac OS X
Building MariaDB Connector/C++ from Source on Windows
Dynamically Linking MariaDB Connector/C++ against the MariaDB Client Library

The MariaDB Connector/C++ is based on the MariaDB Client Library (MySQL C API). MariaDB Connector/C++ is linked against the MariaDB Client Library. You need the MariaDB Client Library installed to compile MariaDB Connector/C++.

You also need the cross-platform build tool CMake 2.4, or newer, and GLib 2.2.3 or newer installed. Check the README file included with the distribution for platform specific notes on building for Windows and SunOS.

Typically the MariaDB Client Library is installed when the MariaDB Server is installed. However, check your operating system documentation for other installation options.

As of MariaDB Connector/C++ version 1.1.0, it is necessary to have the Boost C++ libraries 1.34.0 or newer installed. Boost is only required to build the connector, it is not required to use the connector. You can obtain Boost and its installation instructions from the official site. Once Boost is installed, tell the make system where the Boost files are, by setting the define -DBOOST_ROOT:STRING=. This can be done when initially invoking CMake, for example: 

shell> CMake . -DBOOST_ROOT:STRING=/usr/local/boost_1_40_0

You might need to change /usr/local/boost_1_40_0/ to match your installation. See the , "Building MariaDB Connector/C++ from Source on Unix, Solaris and Mac OS X" and , "Building MariaDB Connector/C++ from Source on Windows" for further details.

Building MariaDB Connector/C++ from Source on Unix, Solaris and Mac OS X

  1. Run CMake to build a Makefile: 

    shell> me@host:/path/to/mysql-connector-cpp> cmake .
-- Check for working C compiler: /usr/local/bin/gcc
-- Check for working C compiler: /usr/local/bin/gcc -- works
[...]
-- Generating done
-- Build files have been written to: /path/to/mysql-connector-cpp/

    On non-Windows systems, CMake first checks to see if the CMake variable MYSQL_CONFIG_EXECUTABLE is set. If it is not found CMake tries to locate mysql_config in the default locations.

    If you have any problems with the configure process please check the troubleshooting instructions below.

  2. Use make to build the libraries. First make sure you have a clean build: 
    shell> me@host:/path/to/mysql-connector-cpp> make clean

    Then build the connector: 

    me@host:/path/to/mysql-connector-cpp> make
[ 1%] Building CXX object »
driver/CMakeFiles/mysqlcppconn.dir/mysql_connection.o
[ 3%] Building CXX object »
driver/CMakeFiles/mysqlcppconn.dir/mysql_constructed_resultset.o
[...]
[100%] Building CXX object examples/CMakeFiles/statement.dir/statement.o Linking CXX executable statement

    If all goes well, you will find the MariaDB Connector/C++ library in /path/to/cppconn/libmysqlcppconn.so.

  3. Finally make sure the header and library files are installed to their correct locations: 
    make install

    Unless you have changed this in the configuration step, the header files are copied to the directory /usr/local/include. The header files copied are mysql_connection.h and mysql_driver.h.

    Again, unless you have specified otherwise, the library files are copied to /usr/local/lib. The files copied are libmysqlcppconn.so, the dynamic library, and libmysqlcppconn-static.a, the static library.

If you encounter any errors, please first carry out the checks shown below:

  1. CMake options: MariaDB installation path, debug version and more

    In case of configuration or compilation problems, check the list of CMake options: 

    shell> me@host:/path/to/mysql-connector-cpp> cmake -L
[...]
CMAKE_BACKWARDS_COMPATIBILITY:STRING=2.4
CMAKE_BUILD_TYPE:STRING=
CMAKE_INSTALL_PREFIX:PATH=/usr/local EXECUTABLE_OUTPUT_PATH:PATH=
LIBRARY_OUTPUT_PATH:PATH=
MYSQLCPPCONN_GCOV_ENABLE:BOOL=0
MYSQLCPPCONN_TRACE_ENABLE:BOOL=0
MYSQL_CONFIG_EXECUTABLE:FILEPATH=/usr/bin/mysql_config

    For example, if your MariaDB Server installation path is not /usr/local/mysql and you want to build a debug version of the MariaDB Connector/C++, use: 

    shell> me@host:/path/to/mysql-connector-cpp> cmake »
-D CMAKE_BUILD_TYPE:STRING=Debug »
-D MYSQL_CONFIG_EXECUTABLE=/path/to/my/mysql/server/bin/mysql_config .
  2. Verify your settings with cmake -L: 
    shell> me@host:/path/to/mysql-connector-cpp> cmake -L
[...]
CMAKE_BACKWARDS_COMPATIBILITY:STRING=2.4
CMAKE_BUILD_TYPE:STRING=
CMAKE_INSTALL_PREFIX:PATH=/usr/local EXECUTABLE_OUTPUT_PATH:PATH=
LIBRARY_OUTPUT_PATH:PATH=
MYSQLCPPCONN_GCOV_ENABLE:BOOL=0
MYSQLCPPCONN_TRACE_ENABLE:BOOL=0
MYSQL_CONFIG_EXECUTABLE=/path/to/my/mysql/server/bin/mysql_config

    Proceed by carrying out a make clean command followed by a make command, as described above.

Once you have installed MariaDB Connector/C++ you can carry out a quick test to check the installation. To do this you can compile and run one of the example programs, such as examples/standalone_example.cpp. This example is discussed in more detail later, but for now you can use it to test the connector has been correctly installed. This procedure assumes you have a working MariaDB Server that you can connect to.

  1. First compile the example. To do this change to the examples directory and type: 

    shell> g++ -o test_install -I/usr/local/include -I/usr/local/include/cppconn -Wl,-Bdynamic -lmysqlcppconn standalone_example.cpp
  2. Make sure the dynamic library which is used in this case can be found at runtime: 
    shell> export LD_LIBRARY_PATH=/usr/local/lib
  3. Now run the program to test your installation, substituting the appropriate host, user, password and database names for your system: 
    ./test_install localhost root password database

    You will see something similar to the following: 

    Connector/C++ standalone program example...
... running 'SELECT 'Welcome to Connector/C++' AS _message'
... MariaDB replies: Welcome to Connector/C++
... say it again, MySQL
....MySQL replies: Welcome to Connector/C++
... find more at http://www.mysql.com

    If you see any errors, take note of them and go through the troubleshooting procedures discussed earlier.

Building MariaDB Connector/C++ from Source on Windows

Note

Please note the only compiler formally supported for Windows is Microsoft Visual Studio 2003 and above.

The basic steps for building the connector on Windows are the same as for Unix. It is important to use CMake 2.6.2 or newer to generate build files for your compiler and to invoke the compiler.Note

On Windows, mysql_config is not present, so CMake will attempt to retrieve the location of MariaDB from the environment variable $ENV{MYSQL_DIR}. If MYSQL_DIR is not set, CMake will then proceed to check for MariaDB in the following locations: $ENV{ProgramFiles}/MySQL/*/include, and $ENV{SystemDrive}/MySQL/*/include.

CMake makes it easy for you to try other compilers. However, you may experience compile warnings, compile errors or linking issues not detected by Visual Studio. Patches are gratefully accepted to fix issues with other compilers.

Consult the CMake manual or check cmake --help to find out which build systems are supported by your CMake version: 

C:\>cmake --help cmake version 2.6-patch 2
Usage
[...]
Generators The following generators are available on this platform:
 Borland Makefiles = Generates Borland makefiles.
 MSYS Makefiles = Generates MSYS makefiles.
 MinGW Makefiles = Generates a make file for use with
 mingw32-make.
 NMake Makefiles = Generates NMake makefiles.
 Unix Makefiles = Generates standard UNIX makefiles.
 Visual Studio 6 = Generates Visual Studio 6 project files.
 Visual Studio 7 = Generates Visual Studio .NET 2002 project
 files.
 Visual Studio 7 .NET 2003 = Generates Visual Studio .NET 2003 project
 files.
 Visual Studio 8 2005 = Generates Visual Studio .NET 2005 project
 files.
 Visual Studio 8 2005 Win64 = Generates Visual Studio .NET 2005 Win64
 project files.
 Visual Studio 9 2008 = Generates Visual Studio 9 2008 project fil
 Visual Studio 9 2008 Win64 = Generates Visual Studio 9 2008 Win64 proje
 files.
[...]

It is likely that your CMake binary will support more compilers, known by CMake as generators, than supported by MariaDB Connector/C++. We have built the connector using the following generators:

Please see the building instructions for Unix, Solaris and Mac OS X for troubleshooting and configuration hints.

The steps to build the connector are given below:

  1. Run CMake to generate build files for your generator:

    Visual Studio

     C:\path_to_mysql_cpp>cmake -G 'Visual Studio 9 2008'
-- Check for working C compiler: cl
-- Check for working C compiler: cl -- works
-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - done
-- Check for working CXX compiler: cl
-- Check for working CXX compiler: cl -- works
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- ENV{MYSQL_DIR} =
-- MariaDB Include dir: C:/Programme/MySQL/MySQL Server 5.1/include
-- MariaDB Library : C:/Progams/MySQL/MySQL Server 5.1/lib/opt/mysqlclient.lib
-- MariaDB Library dir: C:/Progams/MySQL/MySQL Server 5.1/lib/opt
-- MariaDB CFLAGS:
-- MariaDB Link flags:
-- MariaDB Include dir: C:/Progams/MySQL/MySQL Server 5.1/include
-- MariaDB Library dir: C:/Progams/MySQL/MySQL Server 5.1/lib/opt
-- MariaDB CFLAGS:
-- MariaDB Link flags:
-- Configuring cppconn
-- Configuring test cases
-- Looking for isinf
-- Looking for isinf - not found
-- Looking for isinf
-- Looking for isinf - not found.
-- Looking for finite
-- Looking for finite - not found.
-- Configuring C/J junit tests port
-- Configuring examples
-- Configuring done
-- Generating done
-- Build files have been written to: C:\path_to_mysql_cpp C:\path_to_mysql_cpp>dir *.sln *.vcproj
[...]
19.11.2008 12:16 23.332 MYSQLCPPCONN.sln
[...]
19.11.2008 12:16 27.564 ALL_BUILD.vcproj
19.11.2008 12:16 27.869 INSTALL.vcproj
19.11.2008 12:16 28.073 PACKAGE.vcproj
19.11.2008 12:16 27.495 ZERO_CHECK.vcproj

    NMake

     C:\path_to_mysql_cpp>cmake -G 'NMake Makefiles'
-- The C compiler identification is MSVC
-- The CXX compiler identification is MSVC
[...]
-- Build files have been written to: C:\path_to_mysql_cpp
  2. Use your compiler to build MariaDB Connector/C++

    Visual Studio - GUI

    Open the newly generated project files in the Visual Studio GUI or use a Visual Studio command line to build the driver. The project files contain a variety of different configurations. Among them debug and nondebug versions.

    Visual Studio - NMake

    C:\path_to_mysql_cpp>nmake Microsoft (R) Program Maintenance Utility Version 9.00.30729.01
Copyright (C) Microsoft Corporation. All rights reserved.
Scanning dependencies of target mysqlcppconn
[ 2%] Building CXX object driver/CMakeFiles/mysqlcppconn.dir/mysql_connection.obj mysql_connection.cpp
[...]
Linking CXX executable statement.exe
[100%] Built target statement

Dynamically Linking MariaDB Connector/C++ against the MariaDB Client Library

Note

Note this section refers to dynamic linking of the MariaDB Connector/C++ with the client library, not the dynamic linking of the application to MariaDB Connector/C++.

An application that uses MariaDB Connector/C++ can be either statically or dynamically linked to the MariaDB Connector/C++ libraries. MariaDB Connector/C++ is usually statically linked to the underlying MariaDB Client Library (or Connector/C). Note, that unless otherwise stated, reference to the MariaDB Client Library is also taken to include Connector/C, which is a separately packaged, stand alone version of the MariaDB Client Library. From MariaDB Connector/C++ version 1.1.0 it is possible to also dynamically link to the underlying MariaDB Client Library. The ability of MariaDB Connector/C++ to dynamically link to MariaDB Client Library is not enabled by default, and enabling this feature is done through a compile time option, when compiling the MariaDB Connector/C++ source code.

To use the ability to dynamically link the client library to MariaDB Connector/C++, define the MYSQLCLIENT_STATIC_BINDING:BOOL when building the MariaDB Connector/C++ source code: 

rm CMakeCache.txt cmake -DMYSQLCLIENT_STATIC_BINDING:BOOL=1 .
make clean make make install

Note that precompiled binaries of MariaDB Connector/C++ use static binding with the client library by default.

Now, in your application, when creating a connection, MariaDB Connector/C++ will select and load a client library at runtime. It will choose the client library by searching defined locations and environment variables depending on the host operating system. It is also possible when creating a connection in an application to define an absolute path to the client library to be loaded at runtime. This can be convenient if you have defined a standard location from which you want the client library to be loaded. This is sometimes done to circumvent possible conflicts with other versions of the client library that may be located on the system.

MySQL Connector/C++ Building Windows Applications with Microsoft Visual Studio

MySQL Connector/C++ is available as a static or dynamic library to use with your application. This section looks at how to link the library to your application.Note

To avoid potential crashes the build configuration of MariaDB Connector/C++ should match the build configuration of the application using it. For example, do not use the release build of MariaDB Connector/C++ with a debug build of the client application.

Static library

The MariaDB Connector/C++ static library file is mysqlcppconn-static.lib. You link this library statically with your application. Also link against the files libmysql.dll and libmysql.lib. Once linking has been successfully completed, the application will require access to libmysql.dll at run time.

Dynamic library

The MariaDB Connector/C++ dynamic library file is mysqlcppconn.dll. To build your client application, link it with the file mysqlcppconn.lib. At run time, the application will require access to the files mysqlcppconn.dll and libmysql.dll.

Building a MariaDB Connector/C++ application with Microsoft Visual Studio

Initially, the procedure for building an application to use either the static or dynamic library is the same. You then carry out some additional steps depending on whether you are building your application to use the static or dynamic library.

  1. Select File, New, Project from the main menu.

    Figure 20.62. Creating a New Project

    Creating a new project
  2. In the wizard, select Visual C++, Win32. From Visual Studio Installed Templates, select the application type Win32 Console Application. Enter a name for the application, then click OK, to move to the Win32 Application Wizard.

    Figure 20.63. The New Project Dialog Box

    The New Project dialog box
  3. In the Win32 Application Wizard, click Application Settings and ensure the defaults are selected. The radio button Console application and the check box Precompiled headers are selected. Click Finish to close the wizard.

    Figure 20.64. The Win32 Application Wizard

    The Win32 Application Wizard
  4. From the drop down list box on the toolbar, change from the default Debug build to the Release build.

    Figure 20.65. Selecting the Release Build

    Selecting the Release build
  5. From the main menu select Project, Properties. This can also be accessed using the hot key ALT + F7.

    Figure 20.66. Selecting Project Properties from the Main Menu

    Selecting Project Properties from the main menu
  6. Under Configuration Properties, open the tree view.
  7. Select C++, General in the tree view.

    Figure 20.67. Setting Properties

    Setting properties
  8. Now ensure that Visual Studio can find the MariaDB include directory. This directory includes header files that can optionally be installed when installing MariaDB Server.

    Figure 20.68. MariaDB Include Directory

    MySQL include directory
  9. In the Additional Include Directories text field, add the MariaDB include/ directory.

    Figure 20.69. Select Directory Dialog

    Select Directory dialog
  10. Also set the location of additional libraries that Visual Studio needs to build the application. These are located in the MariaDB lib/opt directory, a subdirectory of the MariaDB Server installation directory.

    Figure 20.70. Typical Contents of MariaDB lib/opt Directory

    Typical contents of MariaDB lib/opt directory
  11. In the tree view, open Linker, General, Additional Library Directories.

    Figure 20.71. Additional Library Directories

    Additional Library Directories
  12. Add the lib/opt directory into the Additional Library Directories text field. This enables the library file libmysql.lib to be found.

    Figure 20.72. Additional Library Directories Dialog

    Additional Library Directories dialog

The remaining steps depend on whether you are building an application to use the MariaDB Connector/C++ static or dynamic library. If you are building your application to use the dynamic library go here. If you are building your application to use the static library, carry out the following steps:

  1. Then open Linker, Input, Additional Dependencies.

    Figure 20.73.

  2. Enter mysqlcppconn-static.lib and libmysql.lib.

    Figure 20.74. Adding Additional Dependencies

    Adding additional dependencies
  3. By default CPPCONN_PUBLIC_FUNC is defined to declare functions to be compatible with an application that calls a DLL. If building an application to call the static library, ensure that function prototypes are compatible with this. In this case, define CPPCONN_PUBLIC_FUNC to be an empty string, so that functions are declared with the correct prototype.

    In the Project, Properties tree view, under C++, Preprocessor, enter CPPCONN_PUBLIC_FUNC= into the Preprocessor Definitions text field.

    Figure 20.75. Setting the CPPCONN_PUBLIC_FUNC Define

    Setting the CPPCONN_PUBLIC_FUNC define Note

    Make sure you enter CPPCONN_PUBLIC_FUNC= and not CPPCONN_PUBLIC_FUNC, so that it is defined as an empty string.

If building an application to use the MariaDB Connector/C++ dynamically linked library carry out these steps:

  1. Under Linker, Input, add mysqlcppconn.lib into the Additional Dependencies text field.
  2. mysqlcppconn.dll must be in the same directory as the application executable, or somewhere on the system's path, so that the application can access the MariaDB Connector/C++ Dynamic Linked Library at runtime.

    Copy mysqlcppconn.dll to the same directory as the application. Alternatively, extend the PATH environment variable using SET PATH=%PATH%;C:\path\to\cpp. Alternatively, you can copy mysqlcppconn.dll to the Windows installation Directory, typically c:\windows.

MySQL Connector/C++ Building Linux Applications with NetBeans

This section describes how to build MariaDB Connector/C++ applications for Linux using the NetBeans IDE.

Figure 20.76. The NetBeans IDE

The NetBeans IDE Note

To avoid potential crashes the build configuration of MariaDB Connector/C++ should match the build configuration of the application using it. For example, do not use the release build of MariaDB Connector/C++ with a debug build of the client application.

  1. The first step of building your application is to create a new project. Select File, New Project. Choose a C/C++ Application and click Next.
  2. Give the project a name and click Finish. A new project is created.
  3. In the Projects tab, right-click Source Files and select New, then Main C++ File....
  4. Change the filename, or simply select the defaults and click Finish to add the new file to the project.
  5. Now add some working code to your main source file. Explore your MariaDB Connector/C++ installation and navigate to the examples directory.
  6. Select a suitable example, such as standalone_example_docs1.cpp. Copy all the code in this file, and use it to replace the code in your existing main source file. Amend the code to reflect the connection properties required for your test database. You now have a working example that will access a MariaDB database using MariaDB Connector/C++.
  7. At this point, NetBeans is showing some errors in the source code. Direct NetBeans to the necessary header files to include. Select File, Project Properties from the main menu.
  8. In the Categories: tree view panel, navigate to Build, C++ Compiler.
  9. In the General panel, select Include Directories.
  10. Click the ... button.
  11. Click Add, then navigate to the directory where the MariaDB Connector/C++ header files are located. This will be /usr/local/include unless you have installed the files to a different location. Click Select. Click OK.

    Figure 20.77. Setting the Header Include Directory

    Setting the header include directory
  12. Click OK again to close the Project Properties dialog.

At this point, you have created a NetBeans project, containing a single C++ source file. You have also ensured that the necessary include files are accessible. Before continuing, decide whether your project is to use the MariaDB Connector/C++ static or dynamic library. The project settings are slightly different in each case, because you link against a different library.

Using the static library

To use the static library, link against two library files, libmysqlcppconn-static.a and libmysqlclient.a. The locations of the files depend on your setup, but typically the former are in /usr/local/lib and the latter in /usr/lib. Note the file libmysqlclient.a is not part of MariaDB Connector/C++, but is the MariaDB Client Library file distributed with MariaDB Server. Remember, the MariaDB Client Library is an optional component as part of the MariaDB Server installation process. Note the MariaDB Client Library is also available as part of the MariaDB Connector/C distribution.

  1. The first step is to set the project to link the necessary library files. Select File, Project Properties from the main menu.
  2. In the Categories: tree view, navigate to Linker.
  3. In the General panel, select Additional Library Directories. Click the ... button.
  4. Select and add the /usr/lib and /usr/local/lib directories.
  5. In the same panel, add the two library files required for static linking as discussed earlier. The properties panel should then look similar to the following screenshot:

    Figure 20.78. Setting the Static Library Directories and File Names

    Setting the static library directories and file names
  6. Click OK to close the Project Properties dialog.

Using the dynamic library

For your application to use the MariaDB Connector/C++ dynamic library, you link your project with a single library file, libmysqlcppconn.so. The location of this file depends on how you configured your installation of MariaDB Connector/C++, but is typically /usr/local/lib.

  1. The first step is to set the project to link the necessary library file. Select File, Project Properties from the main menu.
  2. In the Categories: tree view, navigate to Linker.
  3. In the General panel, select Additional Library Directories. Click the ... button.
  4. Select and add the /usr/local/lib directories.
  5. In the same panel, add the library file required for static linking as discussed earlier. The properties panel should then look similar to the following screenshot:

    Figure 20.79. Setting the Dynamic Library Directory and File Name

    Setting the dynamic library directory and file name
  6. Click OK to close the Project Properties dialog.

Having configured your project, you build it by selecting Run, Build Main Project from the main menu. You then run the project using Run, Run Main Project.

On running the application, you should see a screen similar to the following (this is actually the static version of the application shown):

Figure 20.80. The Example Application Running

The example application running Note

Note the above settings and procedures were carried out for the default Debug configuration. To create a Release configuration, select that configuration before setting the Project Properties.

MySQL Connector/C++ Getting Started: Usage Examples

MySQL Connector/C++ Connecting to MySQL
MySQL Connector/C++ Running a simple query
MySQL Connector/C++ Fetching results
MySQL Connector/C++ Using Prepared Statements
MySQL Connector/C++ Complete Example 1
MySQL Connector/C++ Complete Example 2

The download package contains usage examples in the directory examples/. The examples explain the basic usage of the following classes:

The examples cover:

The examples in this document are only code snippets. The code snippets provide a brief overview on the API. They are not complete programs. Please check the examples/ directory of your MariaDB Connector/C++ installation for complete programs. Please also read the README file in the examples/ directory. To test the example code, first edit the examples.h file in the examples/ directory, to add your connection information. Then rebuild the code by issuing a make command.

The examples in the examples/ directory include:

MySQL Connector/C++ Connecting to MariaDB

A connection to MariaDB is established by retrieving an instance of sql::Connection from a sql::mysql::MySQL_Driver object. A sql::mysql::MySQL_Driver object is returned by sql::mysql::MySQL_Driver::get_mysql_driver_instance(). 

sql::mysql::MySQL_Driver *driver;
sql::Connection *con;
driver = sql::mysql::MySQL_Driver::get_mysql_driver_instance();
con = driver->connect('tcp://127.0.0.1:3306', 'user', 'password');
delete con;

Make sure that you free the sql::Connection object as soon as you do not need it any more. But do not explicitly free the connector object!

MySQL Connector/C++ Running a simple query

For running simple queries, you can use the methods sql::Statement::execute(), sql::Statement::executeQuery() and sql::Statement::executeUpdate(). Use the method sql::Statement::execute() if your query does not return a result set or if your query returns more than one result set. See the examples/ directory for more on this. 

sql::mysql::MySQL_Driver *driver;
sql::Connection *con;
sql::Statement *stmt;
driver = sql::mysql::get_mysql_driver_instance();
con = driver->connect('tcp://127.0.0.1:3306', 'user', 'password');
stmt = con->createStatement();
stmt->execute('USE ' EXAMPLE_DB);
stmt->execute('DROP TABLE IF EXISTS test');
stmt->execute('CREATE TABLE test(id INT, label CHAR(1))');
stmt->execute('INSERT INTO test(id, label) VALUES (1, 'a')');
delete stmt;
delete con;

Note that you have to free sql::Statement and sql::Connection objects explicitly using delete.

MySQL Connector/C++ Fetching results

The API for fetching result sets is identical for (simple) statements and prepared statements. If your query returns one result set, use sql::Statement::executeQuery() or sql::PreparedStatement::executeQuery() to run your query. Both methods return sql::ResultSet objects. The preview version does buffer all result sets on the client to support cursors. 

// ...
sql::Connection *con;
sql::Statement *stmt;
sql::ResultSet *res;
// ...
stmt = con->createStatement();
// ...
res = stmt->executeQuery('SELECT id, label FROM test ORDER BY id ASC');
while (res->next()) {
 // You can use either numeric offsets...
 cout << 'id = ' << res->getInt(1); // getInt(1) returns the first column
 // ... or column names for accessing results.
 // The latter is recommended.
 cout << ', label = '' << res->getString('label') << ''' << endl;
}
delete res;
delete stmt;
delete con;
Note

Note in the preceding code snippet that column indexing starts from 1.

Note that you have to free sql::Statement, sql::Connection and sql::ResultSet objects explicitly using delete.

The usage of cursors is demonstrated in the examples contained in the download package.

MySQL Connector/C++ Using Prepared Statements

If you are not familiar with Prepared Statements on MariaDB have an extra look at the source code comments and explanations in the file examples/prepared_statement.cpp.

sql::PreparedStatement is created by passing an SQL query to sql::Connection::prepareStatement(). As sql::PreparedStatement is derived from sql::Statement, you will feel familiar with the API once you have learned how to use (simple) statements (sql::Statement). For example, the syntax for fetching results is identical. 

// ...
sql::Connection *con;
sql::PreparedStatement *prep_stmt
// ...
prep_stmt = con->prepareStatement('INSERT INTO test(id, label) VALUES (?, ?)');
prep_stmt->setInt(1, 1);
prep_stmt->setString(2, 'a');
prep_stmt->execute();
prep_stmt->setInt(1, 2);
prep_stmt->setString(2, 'b');
prep_stmt->execute();
delete prep_stmt;
delete con;

As usual, you have to free sql::PreparedStatement and sql::Connection objects explicitly.

MySQL Connector/C++ Complete Example 1

The following code shows a complete example of how to use MariaDB Connector/C++: 

/* Copyright 2008, 2010, Oracle and/or its affiliates. All rights reserved.
This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; version 2 of the License.
There are special exceptions to the terms and conditions of the GPL as it is applied to this software. View the full text of the exception in file EXCEPTIONS-CONNECTOR-C++ in the directory of this software distribution.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
/* Standard C++ includes */
#include <stdlib.h>
#include <iostream>
/*
 Include directly the different
 headers from cppconn/ and mysql_driver.h + mysql_util.h
 (and mysql_connection.h). This will reduce your build time!
*/
#include 'mysql_connection.h'
#include <cppconn/driver.h>
#include <cppconn/exception.h>
#include <cppconn/resultset.h>
#include <cppconn/statement.h>
using namespace std;
int main(void)
{
cout << endl;
cout << 'Running 'SELECT 'Hello World!' »
 AS _message'...' << endl;
try {
 sql::Driver *driver;
 sql::Connection *con;
 sql::Statement *stmt;
 sql::ResultSet *res;
 /* Create a connection */
 driver = get_driver_instance();
 con = driver->connect('tcp://127.0.0.1:3306', 'root', 'root');
 /* Connect to the MariaDB test database */
 con->setSchema('test');
 stmt = con->createStatement();
 res = stmt->executeQuery('SELECT 'Hello World!' AS _message');
 while (res->next()) {
 cout << '\t... MariaDB replies: ';
 /* Access column data by alias or column name */
 cout << res->getString('_message') << endl;
 cout << '\t... MariaDB says it again: ';
 /* Access column fata by numeric offset, 1 is the first column */
 cout << res->getString(1) << endl;
 }
 delete res;
 delete stmt;
 delete con;
} catch (sql::SQLException &e) {
 cout << '# ERR: SQLException in ' << __FILE__;
 cout << '(' << __FUNCTION__ << ') on line ' »
 << __LINE__ << endl;
 cout << '# ERR: ' << e.what();
 cout << ' (MySQL error code: ' << e.getErrorCode();
 cout << ', SQLState: ' << e.getSQLState() << ' )' << endl;
}
cout << endl;
return EXIT_SUCCESS;
}

MySQL Connector/C++ Complete Example 2

The following code shows a complete example of how to use MariaDB Connector/C++: 

/* Copyright 2008, 2010, Oracle and/or its affiliates. All rights reserved.
This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; version 2 of the License.
There are special exceptions to the terms and conditions of the GPL as it is applied to this software. View the full text of the exception in file EXCEPTIONS-CONNECTOR-C++ in the directory of this software distribution.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
/* Standard C++ includes */
#include <stdlib.h>
#include <iostream>
/*
 Include directly the different
 headers from cppconn/ and mysql_driver.h + mysql_util.h
 (and mysql_connection.h). This will reduce your build time!
*/
#include 'mysql_connection.h'
#include <cppconn/driver.h>
#include <cppconn/exception.h>
#include <cppconn/resultset.h>
#include <cppconn/statement.h>
#include <cppconn/prepared_statement.h>
using namespace std;
int main(void)
{
cout << endl;
cout << 'Let's have MariaDB count from 10 to 1...' << endl;
try {
 sql::Driver *driver;
 sql::Connection *con;
 sql::Statement *stmt;
 sql::ResultSet *res;
 sql::PreparedStatement *pstmt;
 /* Create a connection */
 driver = get_driver_instance();
 con = driver->connect('tcp://127.0.0.1:3306', 'root', 'root');
 /* Connect to the MariaDB test database */
 con->setSchema('test');
 stmt = con->createStatement();
 stmt->execute('DROP TABLE IF EXISTS test');
 stmt->execute('CREATE TABLE test(id INT)');
 delete stmt;
 /* '?' is the supported placeholder syntax */
 pstmt = con->prepareStatement('INSERT INTO test(id) VALUES (?)');
 for (int i = 1; i <= 10; i++) {
 pstmt->setInt(1, i);
 pstmt->executeUpdate();
 }
 delete pstmt;
 /* Select in ascending order */
 pstmt = con->prepareStatement('SELECT id FROM test ORDER BY id ASC');
 res = pstmt->executeQuery();
 /* Fetch in reverse = descending order! */
 res->afterLast();
 while (res->previous())
 cout << '\t... MariaDB counts: ' << res->getInt('id') << endl;
 delete res;
 delete pstmt;
 delete con;
} catch (sql::SQLException &e) {
 cout << '# ERR: SQLException in ' << __FILE__;
 cout << '(' << __FUNCTION__ << ') on line ' »
 << __LINE__ << endl;
 cout << '# ERR: ' << e.what();
 cout << ' (MySQL error code: ' << e.getErrorCode();
 cout << ', SQLState: ' << e.getSQLState() << »
 ' )' << endl;
}
cout << endl;
return EXIT_SUCCESS;
}

MySQL Connector/C++ Tutorials

Tutorial: Calling Stored Procedures with Statements in MariaDB Connector/C++
Tutorial: Calling Stored Procedures with Prepared Statements in MariaDB Connector/C++

Here are some tutorials on using MariaDB Connector/C++. Also consult the examples in , "MySQL Connector/C++ Getting Started: Usage Examples".

Setting up the World database for use in the tutorials

These tutorials refer to tables and sample data from the World database, which you can download from the MySQL Documentation page. Look for the section called "Example Databases".

Tutorial framework code

These examples all use the following framework, to avoid repeating code: 

#include <stdlib.h>
#include <iostream>
#include <sstream>
#include <stdexcept>
#include 'mysql_connection.h'
#include <cppconn/driver.h>
#include <cppconn/exception.h>
#include <cppconn/resultset.h>
#include <cppconn/statement.h>
#include <cppconn/prepared_statement.h>
#define EXAMPLE_HOST 'localhost'
#define EXAMPLE_USER 'root'
#define EXAMPLE_PASS ''
#define EXAMPLE_DB 'world'
using namespace std;
int main(int argc, const char **argv)
{ 
 string url(argc >= 2 ? argv[1] : EXAMPLE_HOST);
 const string user(argc >= 3 ? argv[2] : EXAMPLE_USER);
 const string pass(argc >= 4 ? argv[3] : EXAMPLE_PASS);
 const string database(argc >= 5 ? argv[4] : EXAMPLE_DB);
 cout << 'Connector/C++ tutorial framework...' << endl;
 cout << endl;
 try {
 /* INSERT TUTORIAL CODE HERE! */
 } catch (sql::SQLException &e) {
 /*
 The MariaDB Connector/C++ throws three different exceptions:
 - sql::MethodNotImplementedException (derived from sql::SQLException)
 - sql::InvalidArgumentException (derived from sql::SQLException)
 - sql::SQLException (derived from std::runtime_error)
 */
 cout << '# ERR: SQLException in ' << __FILE__;
 cout << '(' << __FUNCTION__ << ') on line ' << __LINE__ << endl;
 /* Use what() (derived from std::runtime_error) to fetch the error message */
 cout << '# ERR: ' << e.what();
 cout << ' (MySQL error code: ' << e.getErrorCode();
 cout << ', SQLState: ' << e.getSQLState() << ' )' << endl;
 return EXIT_FAILURE;
 }
 cout << 'Done.' << endl;
 return EXIT_SUCCESS;
}

To compile and run the framework

First, copy and paste the framework code to a file such as frmwk.cpp. Edit the #define statements to reflect your connection details (server, user, password, database).

To compile the framework, for example on Mac OS X, type: 

shell> g++ -o frmwk -I/usr/local/include -I/usr/local/include/cppconn -lmysqlcppconn frmwk.cpp

To run the framework, enter the following: 

shell> ./frmwk

You will see a simple message. You are now ready to continue to the tutorials.

Tutorial: Calling Stored Procedures with Statements in MariaDB Connector/C++

Stored procedures can be called using both Statements and Prepared Statements. This tutorial looks at calling stored procedures using Statements. The following tutorial , "Tutorial: Calling Stored Procedures with Prepared Statements in MariaDB Connector/C++" will cover the use of Prepared Statements.

You can construct and call various combinations of stored procedures:

  1. A stored procedure that does not return any result. For example, such a stored procedure can log non-critical information, or change database data in a straightforward way.
  2. A stored procedure that returns an output parameter. For example, such a procedure can indicate success or failure, query a single item of data, or combine multiple data items into a single result.
  3. A stored procedure that returns a result set. The procedure can execute a query that matches an arbitrary number of table rows. Your application loops through the result set to display, transform, or otherwise process each item.

The following stored procedures illustrate each of these scenarios.

The following routine adds a country into the World database, but does not return a result. This corresponds to Scenario 1 above. 

CREATE PROCEDURE add_country (IN country_code CHAR(3), IN country_name CHAR(52), IN continent_name CHAR(30))
BEGIN
 INSERT INTO Country(Code, Name, Continent) VALUES (country_code, country_name, continent_name);
END

The next routine returns the population of a specified country, and corresponds to Scenario 2 above: 

CREATE PROCEDURE get_pop (IN country_name CHAR(52), OUT country_pop INT(11))
BEGIN
 SELECT Population INTO country_pop FROM Country WHERE Name = country_name;
END

The next routine is an example of a procedure returning a result set containing multiple records. This routine corresponds to Scenario 3 above. 

CREATE PROCEDURE get_data ()
BEGIN
 SELECT Code, Name, Population, Continent FROM Country WHERE Continent = 'Oceania' AND Population < 10000;
 SELECT Code, Name, Population, Continent FROM Country WHERE Continent = 'Europe' AND Population < 10000;
 SELECT Code, Name, Population, Continent FROM Country WHERE Continent = 'North America' AND Population < 10000;
END

Enter and test the stored procedures to ensure no errors have been introduced. You are now ready to start writing applications using Connector/C++ that call stored procedures.

Scenario 1 - Stored procedure does not return a result set

The first case illustrates Scenario 1, calling a Stored procedure that does not return a result set.

  1. Make a copy of the tutorial framework code.
  2. Insert the following code into the framework at the correct location (denoted by an INSERT HERE comment in the framework). 
    sql::Driver* driver = get_driver_instance();
std::auto_ptr<sql::Connection> con(driver->connect(url, user, pass));
con->setSchema(database);
std::auto_ptr<sql::Statement> stmt(con->createStatement());
// We don't need to check the return value explicitly, if it indicates
// an error Connector/C++ will generate an exception.
stmt->execute('CALL add_country(\'ATL\', \'Atlantis\', \'North America\')');
  3. Compile the program using the following command: 
    shell> g++ -o sp_scenario1 -I/usr/local/include/cppconn/ -lmysqlcppconn sp_scenario1.cpp
  4. Run the program by typing: 
    shell> ./sp_scenario1
  5. Using the mysql Command Line Client, or other suitable tool, check the World database to determine that it has been updated correctly. You can use a query such as: 
    SELECT Code, Name, Continent FROM Country WHERE Code="ATL";

The code in this case simply creates a statement and then invokes the execute method on it, passing the call to the stored procedure as a parameter. The stored procedure itself does not return a value, although it is important to note there will always be a return value from the call - this is simply the call status. MariaDB Connector/C++ handles this status for you, so you do not need code to handle it explicitly. If the call fails for some reason, an exception will be raised, and this will be handled by the catch statement in the code.

Scenario 2 - Stored procedure returns an output parameter

You will now see how to handle a stored procedure that returns an output parameter.

  1. Enter the following code into the tutorial framework code: 

    sql::Driver* driver = get_driver_instance();
std::auto_ptr<sql::Connection> con(driver->connect(url, user, pass));
con->setSchema(database);
std::auto_ptr<sql::Statement> stmt(con->createStatement());
stmt->execute('CALL get_pop(\'Uganda\', @pop)');
std::auto_ptr<sql::ResultSet> res(stmt->executeQuery('SELECT @pop AS _reply'));
while (res->next())
 cout << 'Population of Uganda: ' << res->getString('_reply') << endl;
stmt->execute('CALL get_pop_continent(\'Asia\', @pop)');
res.reset(stmt->executeQuery('SELECT @pop AS _reply'));
while (res->next())
 cout << 'Population of Asia: ' << res->getString('_reply') << endl;
stmt->execute('CALL get_world_pop(@pop)');
res.reset(stmt->executeQuery('SELECT @pop AS _reply'));
while (res->next())
 cout << 'Population of World: ' << res->getString('_reply') << endl;
  2. Compile the program using the following command: 
    shell> g++ -o sp_scenario2 -I/usr/local/include/cppconn/ -lmysqlcppconn sp_scenario2.cpp
  3. Run the program by typing: 
    shell> ./sp_scenario2

    Note the output generated by the program.

In this scenario, the stored procedure sets an output parameter. This is not returned as such, but needs to be obtained using a query. If running the SQL statements directly, this might be similar to the following: 

CALL get_world_pop(@pop);
SELECT @pop;

In the C++ code, a similar sequence is carried out. First, the CALL is executed as seen earlier. To obtain the output parameter, an additional query must be executed. This query results in a ResultSet that can then be processed in a while loop. The simplest way to retrieve the data in this case is to use a getString method on the ResultSet, passing the name of the variable to access. In this example _reply is used as a placeholder for the variable and therefore is used as the key to access the correct element of the result dictionary.

Scenario 3 - Stored procedure returns a Result Set

You will now see how to handle a stored procedure that returns a result set.

  1. Enter the following code into the tutorial framework code: 

    sql::Driver* driver = get_driver_instance();
std::auto_ptr<sql::Connection> con(driver->connect(url, user, pass));
con->setSchema(database);
std::auto_ptr<sql::Statement> stmt(con->createStatement());
stmt->execute('CALL get_stats()');
std::auto_ptr< sql::ResultSet > res;
do {
 res.reset(stmt->getResultSet());
 while (res->next()) {
 cout << 'Result: ' << res->getString(1) << endl;
 }
} while (stmt->getMoreResults());
  2. Compile the program using the following command: 
    shell> g++ -o sp_scenario3 -I/usr/local/include/cppconn/ -lmysqlcppconn sp_scenario3.cpp
  3. Run the program by typing: 
    shell> ./sp_scenario3

    Note the output generated by the program.

The code is similar to the examples you have previously seen. The code of particular interest in this case is: 

do {
 res.reset(stmt->getResultSet());
 while (res->next()) {
 cout << 'Name: ' << res->getString('Name') 
 << ' Population: ' << res->getInt('Population')
 << endl;
 }
} while (stmt->getMoreResults());

The CALL is executed as before, with the results being returned into multiple ResultSets. This is because the Stored Procedure in this case uses multiple SELECT statements. In this example, the output shows that three Result Sets are processed, because there are three SELECT statements in the Stored Procedure. All of the Result Sets have more than one row.

The results are processed using the pattern: 

do {
 Get Result Set
 while (Get Result) {
 Process Result
 }
} while (Get More Result Sets);
Note

This pattern would be used even if the Stored Procedure carried out a single SELECT and you knew there was only one result set. This is a requirement of the underlying protocol.

Tutorial: Calling Stored Procedures with Prepared Statements in MariaDB Connector/C++

Before working through this tutorial, it is recommended you first work through the previous tutorial , "Tutorial: Calling Stored Procedures with Statements in MariaDB Connector/C++".

Scenario 1 - Using a Prepared Statement to prepare a Stored Procedure that does not return a result set

  1. Add the following code to the try block of the tutorial framework: 

    vector<string> code_vector;
code_vector.push_back('SLD');
code_vector.push_back('DSN');
code_vector.push_back('ATL');
vector<string> name_vector;
name_vector.push_back('Sealand');
name_vector.push_back('Disneyland');
name_vector.push_back('Atlantis');
vector<string> cont_vector;
cont_vector.push_back('Europe');
cont_vector.push_back('North America');
cont_vector.push_back('Oceania');
sql::Driver * driver = get_driver_instance();
std::auto_ptr< sql::Connection > con(driver->connect(url, user, pass));
con->setSchema(database);
std::auto_ptr< sql::PreparedStatement > pstmt;
pstmt.reset(con->prepareStatement('CALL add_country(?,?,?)'));
for (int i=0; i<3; i++)
{
 pstmt->setString(1,code_vector[i]);
 pstmt->setString(2,name_vector[i]);
 pstmt->setString(3,cont_vector[i]);
 pstmt->execute(); 
}

    Also, add #include <vector> to the top of your code, because vectors are used to store sample data.

  2. Compile the code using the following command: 
    g++ -o ps_scenario1 -I/usr/local/include/cppconn/ -lmysqlcppconn ps_scenario1.cpp
  3. Run the code using the command: 
    ./ps_scenario1
  4. You can test the database has been updated correctly by using a query such as: 
    SELECT Code, Name, Continent FROM Country WHERE Code = 'DSN' OR Code="ATL" OR Code="SLD";

The code is relatively simple, as no processing is required to handle Result Sets. The procedure call, CALL add_country(?,?,?), is made using placeholders for input parameters denoted by '?'. These placeholders are replaced by values using the Prepared Statement's setString method in this case. The for loop is set up to iterate 3 times, as there are three data sets in this example. The same Prepared Statement is executed three times, each time with different input parameters.

Scenario 2 - Using a Prepared Statement to prepare a Stored Procedure that uses an output parameter

In this scenario a different Stored Procedure is going to be used compared to the one used in the tutorial , "Tutorial: Calling Stored Procedures with Statements in MariaDB Connector/C++". This is to illustrate passing an input parameter as well as fetching an output parameter. The stored routine is as follows: 

CREATE PROCEDURE get_pop_continent (IN continent_name CHAR(30), OUT continent_pop INT(11))
BEGIN
 SELECT SUM(Population) INTO continent_pop FROM Country WHERE Continent = continent_name;
END
  1. Copy the following code into the try block of the tutorial framework code: 

    vector<string> cont_vector;
cont_vector.push_back('Europe');
cont_vector.push_back('North America');
cont_vector.push_back('Oceania');
sql::Driver * driver = get_driver_instance();
std::auto_ptr< sql::Connection > con(driver->connect(url, user, pass));
con->setSchema(database);
std::auto_ptr< sql::Statement > stmt(con->createStatement());
std::auto_ptr< sql::PreparedStatement > pstmt;
std::auto_ptr< sql::ResultSet > res;
pstmt.reset(con->prepareStatement('CALL get_pop_continent(?,@pop)'));
for (int i=0; i<3; i++)
{
 pstmt->setString(1,cont_vector[i]);
 pstmt->execute(); 
 res.reset(stmt->executeQuery('SELECT @pop AS _population'));
 while (res->next())
 cout << 'Population of ' << cont_vector[i] << ' is ' << res->getString('_population') << endl;
}

    You will also need to add the line #include <vector> to the top of the code, as vectors are used in this example.

  2. Compile the code using: 
    shell> g++ -o ps_scenario2 -I/usr/local/include/cppconn/ -lmysqlcppconn ps_scenario2.cpp
  3. Run the code using: 
    shell> ./ps_scenario2
  4. Make a note of the output.

In this scenario a Prepared Statement is created that calls the Stored Procedure get_pop_continent. This procedure takes an input parameter, and also returns an output parameter. The approach used is to create another statement that can be used to fetch the output parameter using a SELECT query. Note that when the Prepared Statement is created, the input parameter to the Stored Procedure is denoted by '?'. Prior to execution of Prepared Statement it is necessary to replace this placeholder by an actual value. This is done using methods such as setString and setInt, for example: 

pstmt->setString(1,cont_vector[i]);

Although for the query used to obtain the output parameter a single result set is expected, it is important to use the while loop to catch more than one result, to avoid the possibility of the connection becoming unstable.

Scenario 3 - Using a Prepared Statement to prepare a Stored Procedure that returns multiple Result Sets

Note

Note this scenario is not supported on versions of MariaDB prior to 5.5.3. This is due to a limitation in the client/server protocol.

  1. Enter the following code into the try block of the tutorial framework: 

    sql::Driver * driver = get_driver_instance();
std::auto_ptr< sql::Connection > con(driver->connect(url, user, pass));
con->setSchema(database);
std::auto_ptr< sql::PreparedStatement > pstmt;
std::auto_ptr< sql::ResultSet > res;
pstmt.reset(con->prepareStatement('CALL get_data()'));
res.reset(pstmt->executeQuery());
do {
 res.reset(pstmt->getResultSet());
 while (res->next()) {
 cout << 'Name: ' << res->getString('Name') 
 << ' Population: ' << res->getInt('Population')
 << endl;
 }
} while (pstmt->getMoreResults());
  2. Compile the code using the following command: 
    shell> g++ -o ps_scenario3 -I/usr/local/include/cppconn/ -lmysqlcppconn ps_scenario3.cpp
  3. Run the program using the command: 
    shell> ./ps_scenario3
  4. Make a note of the output generated.

The code executes the Stored Procedure using a Prepared Statement. The standard do-while construct is used to ensure that all Result Sets are fetched. In this case the returned values are fetched from the Result Sets using the getInt and getString methods.

MySQL Connector/C++ Debug Tracing

Although a debugger can be used to debug your application, you may find it beneficial to turn on the debug traces of the connector. Some problems happen randomly which makes them difficult to debug using a debugger. In such cases debug traces and protocol files are more useful because they allow you to trace the activities of all instances of your program.

DTrace is a very powerful technology to trace any application without having to develop an extra trace module for your application. Unfortunately, DTrace is currently only available on Solaris, MacOS 10.5, and FreeBSD.

The MariaDB Connector/C++ can write two trace files:

  1. Trace file generated by the MariaDB Client Library
  2. Trace file generated internally by MariaDB Connector/C++

The first trace file can be generated by the underlying MariaDB Client Library (libmysql). To enable this trace, the connector will call the C-API function mysql_debug() internally. As only debug versions of the MariaDB Client Library are capable of writing a trace file, compile MariaDB Connector/C++ against a debug version of the library if you want to utilize this trace. The trace shows the internal function calls and the addresses of internal objects as shown below: 

>mysql_stmt_init
| >_mymalloc
| | enter: Size: 816
| | exit: ptr: 0x68e7b8
| <_mymalloc | >init_alloc_root
| | enter: root: 0x68e7b8
| | >_mymalloc
| | | enter: Size: 2064
| | | exit: ptr: 0x68eb28
[...]

The second trace is the MariaDB Connector/C++ internal trace. It is available with debug and nondebug builds of the connector as long as you have enabled the tracing module at compile time using cmake -DMYSQLCPPCONN_TRACE_ENABLE:BOOL=1. By default, the tracing functionality is not available and calls to trace functions are removed by the preprocessor.

Compiling the connector with tracing functionality enabled will cause two additional tracing function calls per each connector function call. Run your own benchmark to find out how much this will impact the performance of your application.

A simple test using a loop running 30,000 INSERT SQL statements showed no significant real-time impact. The two variants of this application using a trace enabled and trace disabled version of the connector performed equally well. The run time measured in real-time was not significantly impacted as long as writing a debug trace was not enabled. However, there will be a difference in the time spent in the application. When writing a debug trace the IO subsystem may become a bottleneck.

In summary, use connector builds with tracing enabled carefully. Trace enabled versions may cause higher CPU usage even if the overall run time of your application is not impacted significantly. 

| INF: Tracing enabled
<MySQL_Connection::setClientOption
>MySQL_Prepared_Statement::setInt
| INF: this=0x69a2e0
| >MySQL_Prepared_Statement::checkClosed
| <MySQL_Prepared_Statement::checkClosed
| <MySQL_Prepared_Statement::setInt
[...]

The example from examples/debug_output.cpp demonstrates how to activate the debug traces in your program. Currently they can only be activated through API calls. The traces are controlled on a per-connection basis. You can use the setClientOptions() method of a connection object to activate and deactivate the generation of a trace. The MariaDB Client Library trace is always written into a file, whereas the connector's protocol messages are printed to standard out. 

sql::Driver *driver;
int on_off = 1;
/* Using the Driver to create a connection */
driver = get_driver_instance();
std::auto_ptr< sql::Connection > con(driver->connect(host, user, pass));
/*
Activate debug trace of the MariaDB Client Library (C-API)
Only available with a debug build of the MariaDB Client Library!
*/
con->setClientOption('libmysql_debug', 'd:t:O,client.trace');
/*
Tracing is available if you have compiled the driver using cmake -DMYSQLCPPCONN_TRACE_ENABLE:BOOL=1
*/
con->setClientOption('client_trace', &on_off);

MySQL Connector/C++ Usage Notes

See the JDBC overview for information on JDBC 4.0. Please also check the examples/ directory of the download package.

MySQL Connector/C++ Known Bugs and Issues

Note

Please report bugs through MySQL Bug System .

Known bugs:

None.

Known issues:

See also the MariaDB Connector/C++ Changelogs which can be found here "MySQL Connector/C++ Change History".

MySQL Connector/C++ Feature requests

You can suggest new features in the first instance by joining the mailing list or forum and talking with the developers directly. See , "MySQL Connector/C++ Support"

The following feature requests are currently being worked on:

MySQL Connector/C++ Support

For general discussion of the MariaDB Connector/C++ please use the C/C++ community forum or join the MySQL Connector/C++ mailing list.

Bugs can be reported at the MySQL bug Web site.

For Licensing questions, and to purchase MariaDB Products and Services, please http://www.mysql.com/buy-mysql/

The MariaDB Connector/C++ Changelogs can be found here "MySQL Connector/C++ Change History"

MySQL Connector/C++ FAQ

Questions

Questions and Answers

21.5.12.1: What is MariaDB Connector/C++?

MySQL Connector/C++ is a MariaDB database connector for C++. It allows you develop applications in C++ that connect to the MariaDB Server. MariaDB Connector/C++ is compatible with the JDBC 4.0 API.

21.5.12.2: Are any MariaDB products using MariaDB Connector/C++?

Yes, MariaDB Workbench and MariaDB Connector/OpenOffice.org.

21.5.12.3: Does MariaDB Connector/C++ implement the client/server protocol?

No. MariaDB Connector/C++ uses the MariaDB Client Library for the client/server communication.

21.5.12.4: Which MariaDB Server version(s) is MariaDB Connector/C++ compatible with?

MySQL Connector/C++ fully supports MariaDB Server 5.1 and later.

MySQL Connector/C

Building MariaDB Connector/C from the Source Code
Testing MariaDB Connector/C
MySQL Connector/C FAQ

What is MariaDB Connector/C?

MySQL Connector/C is a C client library for client/server communication. It is a standalone replacement for the MariaDB Client Library shipped with the MariaDB Server.

Why have a replacement for MariaDB Client Library?

There is no need to compile or install the MariaDB Server package if you only need the client library.

MySQL Connector/C does not rely on the MariaDB Server release cycle, so bug fixes and new features are released more often.

MySQL Connector/C API documentation is available here , "C API Function Descriptions".

Supported platforms include:

Building MariaDB Connector/C from the Source Code

Obtaining the Source Code

You can download a tar file containing the source code from the MariaDB Developers site. Select the source code package from the drop down list.

The source code for development releases of the connector can be found at http://launchpad.net/libmysql on the Launchpad site.

The source code for the 1.0 branch is also available on the Launchpad site.

To get the code, you must have Bazaar installed. Use the command bzr branch lp:libmysql.

Build Options

The following options can be used when building the MariaDB Connector/C source code:

Build Option Description
-DWITH_OPENSSL=1 Enables dynamic linking to the system OpenSSL library.
-DWITH_EXTERNAL_ZLIB=1 Enables dynamic linking to the system Zlib library.

Testing MariaDB Connector/C

For testing MariaDB Connector/C, you need a running MariaDB server instance. Before you run the test suite, specify the following environment variables:

To run the test suite, execute ctest from the command line: 

shell> ctest

MySQL Connector/C FAQ

Questions

Questions and Answers

21.6.3.1: What is the "MySQL Native C API"? What are its typical benefits and use cases?

MySQL Connector/C, also known as libmysql, or MariaDB Native C API, is a standalone, C-based API and library that you can use in C applications to connect with the MariaDB Server. It implements the same MariaDB client API that has been in use for a decade.

It is also used as the foundation for drivers for standard database APIs such as ODBC, Perl's DBI, and Python's DB API.

21.6.3.2: What is "libmysql"?

libmysql is the name of the library that MariaDB Connector/C provides.

21.6.3.3: What is "libmysqld"?

libmysqld is an embedded database server with the same API as MariaDB Connector/C. It is included with the MariaDB Server distribution.

21.6.3.4: What is "MySQL Connector/C"?

MySQL Connector/C is a standalone distribution of the libmysql library, which was previously only available as part of the MariaDB Server distribution. The version of libmysql included with MariaDB Connector/C and the version bundled with the server are functionally equivalent, but the cross-platform build system for MariaDB Connector/C uses CMake.

21.6.3.5: What is the difference between "Native C API", "libmysql", "libmysqld" and "MySQL Connector/C"?

MySQL Connector/C and libmysql are the "native C API for MySQL", and all three terms can be used interchangeably. "libmysqld" is the embedded version of the MariaDB Server, and is included in the server distribution.

21.6.3.6: Does MariaDB Connector/C replace any of "Native C API", "libmysql" and "libmysqld"?

MySQL Connector/C contains libmysql, and implements a native C API. It does not include libmysqld, which can be found with the MariaDB server distribution.

MySQL Connector/OpenOffice.org

Installation
Getting Started: Connecting to MySQL
Getting Started: Usage Examples
References
Known Bugs
Contact

MySQL Connector/OpenOffice.org is a native MariaDB database connector for OpenOffice.org. Currently, it is in preview status and supports OpenOffice.org 3.1 and above. It can be used to connect OpenOffice.org applications to a MariaDB server.

Before MariaDB Connector/OpenOffice.org became available you would have to use MariaDB Connector/J (JDBC) or MariaDB Connector/ODBC to connect to a MariaDB server.

Connector/OpenOffice.org is a community project. The source code for Connector/OpenOffice.org is available under GPL with the FLOSS License Exception.

Advantages

Using MariaDB Connector/OpenOffice.org has the following advantages:

Status

MySQL Connector/OpenOffice.org is currently at version 1.0 GA.

If you have any queries please contact us through our mailing list at <users@dba.openoffice.org>

Installation

  1. Install or upgrade to OpenOffice.org 3.1.
  2. Download MariaDB Connector/OpenOffice.org from The OpenOffice.org extension download site. Save the file corresponding to your platform. Currently supported platforms are Windows, Linux, Linux x86-64, Mac OS X, Solaris x86 and Solaris SPARC.
  3. Add the .oxt extension through the Extension Manager of OpenOffice.org. In OpenOffice.org, select Tools, Extension Manager... and specify the .oxt file as a new extension. When done, MariaDB Connector/OpenOffice.org will show up as a new extension in the Extension Manager.

    Figure 20.81. Adding an Extension

    Adding an extension
  4. Restart OpenOffice.org.

Getting Started: Connecting to MariaDB

MySQL Connector/OpenOffice.org enables you to access the MariaDB Server and its schemata from the OpenOffice.org suite.

The following example demonstrates the creation of a new OpenOffice.org Base database which uses a local MariaDB Server for storage and the new connector for connecting.

  1. Select the database

    Create a new database by selecting File, New, Database. This starts a wizard that enables you to create a new database, open an existing database, or connect to an existing database. Select the Connect to existing database radio button. From the listbox select MySQL. Click Next >>.

    Figure 20.82. Selecting the Database

    Selecting the database
  2. You will be asked how you would like to connect to the database. Select the Connect native radio button.

    Figure 20.83. Selecting the connection type

    Selecting the connection type

    Click Next >>.

  3. Fill in the connection settings

    Enter the name of the database, server URL, and optionally the socket to connect on (if not using the default).

    Note that if you do not specify a database all databases will be available for selection.

    Figure 20.84. Entering Connection Settings

    Entering connection settings

    Click Next >>.

  4. Set up user authentication

    If you are using MariaDB server's anonymous account without a password, you do not have to fill in anything in this step. Otherwise, fill in your MariaDB user name and check the password check box. Note, for security reasons, you should not normally use the anonymous account without a password.

    Figure 20.85. Setting Up User Authentication

    Setting up user authentication

    You can now test your connection to the MariaDB database server by clicking the Test Connection button. Check the check box if you do not want OpenOffice.org to ask you for your password again in the current session. Testing the connection is optional, although recommended.

    Click Next >>.

  5. Decide how to proceed after connecting to the database

    Figure 20.86. After Connecting to the Database

    After Connecting to the Database

    Keep the default settings.

    Click Finish.

  6. You will then be prompted to save you database as a database file. Enter the name of the database and the location in which to save the file.

    Figure 20.87. Entering the Database File Name

    Entering the Database File Name

    Click Save.

You will be located in the Base application with your database tables displayed.

Getting Started: Usage Examples

Listing Tables

In the Database area of the Base main window, select Tables. If this is the first time you are accessing the database you will be prompted for your credentials (user name and password); you can store these settings for your current Base session.

Figure 20.88. Listing Tables

Listing tables

Depending on your connection settings you will now see all databases with all their tables, or just the database you have specified in the connection settings.

References

See the OpenOffice.org Web site for documentation of the office suite and its Extension Manager.

Known Bugs

If you discover a bug in Connector/OpenOffice.org please add it to this list and send an email to <users@dba.openoffice.org>. You need to be logged in with an OpenOffice.org account for both; see the project mailing list for details.

Contact

To discuss the new MariaDB Connector/OpenOffice.org, please subscribe to the mailing list <users@dba.openoffice.org>. It is a low-volume list with less than 10 mails per day.

libmysqld, the Embedded MariaDB Server Library

Compiling Programs with libmysqld
Restrictions When Using the Embedded MariaDB Server
Options with the Embedded Server
Embedded Server Examples
Licensing the Embedded Server

The embedded MariaDB server library makes it possible to run a full-featured MariaDB server inside a client application. The main benefits are increased speed and more simple management for embedded applications.

The embedded server library is based on the client/server version of MySQL, which is written in C/C++. Consequently, the embedded server also is written in C/C++. There is no embedded server available in other languages.

The API is identical for the embedded MariaDB version and the client/server version. To change a threaded application to use the embedded library, you normally only have to add calls to the following functions.

Function When to Call
mysql_library_init() Call it before any other MariaDB function is called, preferably early in the main() function.
mysql_library_end() Call it before your program exits.
mysql_thread_init() Call it in each thread you create that accesses MySQL.
mysql_thread_end() Call it before calling pthread_exit()

Then, link your code with libmysqld.a instead of libmysqlclient.a. To ensure binary compatibility between your application and the server library, always compile your application against headers for the same series of MariaDB that was used to compile the server library. For example, if libmysqld was compiled against MariaDB 5.1 headers, do not compile your application against MariaDB 5.5 headers, or vice versa.

Because the mysql_library_xxx() functions are also included in libmysqlclient.a, you can change between the embedded and the client/server version by just linking your application with the right library. See , "mysql_library_init()".

One difference between the embedded server and the standalone server is that for the embedded server, authentication for connections is disabled by default. To use authentication for the embedded server, define the HAVE_EMBEDDED_PRIVILEGE_CONTROL compiler flag when you invoke CMake to configure your MariaDB distribution. See , "MySQL Source-Configuration Options".

Compiling Programs with libmysqld

In precompiled binary MariaDB distributions that include libmysqld, the embedded server library, MariaDB builds the library using the appropriate vendor compiler if there is one.

To get a libmysqld library if you build MariaDB from source yourself, you should configure MariaDB with the -DWITH_EMBEDDED_SERVER=1 option. See , "MySQL Source-Configuration Options".

When you link your program with libmysqld, you must also include the system-specific pthread libraries and some libraries that the MariaDB server uses. You can get the full list of libraries by executing mysql_config --libmysqld-libs.

The correct flags for compiling and linking a threaded program must be used, even if you do not directly call any thread functions in your code.

To compile a C program to include the necessary files to embed the MariaDB server library into an executable version of a program, the compiler will need to know where to find various files and need instructions on how to compile the program. The following example shows how a program could be compiled from the command line, assuming that you are using gcc, use the GNU C compiler: 

gcc mysql_test.c -o mysql_test -lz \
`/usr/local/mysql/bin/mysql_config --include --libmysqld-libs`

Immediately following the gcc command is the name of the C program source file. After it, the -o option is given to indicate that the file name that follows is the name that the compiler is to give to the output file, the compiled program. The next line of code tells the compiler to obtain the location of the include files and libraries and other settings for the system on which it is compiled. Because of a problem with mysql_config, the option -lz (for compression) is added here. The mysql_config command is contained in backticks, not single quotation marks.

On some non-gcc platforms, the embedded library depends on C++ runtime libraries and linking against the embedded library might result in missing-symbol errors. To solve this, link using a C++ compiler or explicitly list the required libraries on the link command line.

Restrictions When Using the Embedded MariaDB Server

The embedded server has the following limitations:

Some of these limitations can be changed by editing the mysql_embed.h include file and recompiling MySQL.

Options with the Embedded Server

Any options that may be given with the mysqld server daemon, may be used with an embedded server library. Server options may be given in an array as an argument to the mysql_library_init(), which initializes the server. They also may be given in an option file like my.cnf. To specify an option file for a C program, use the --defaults-file option as one of the elements of the second argument of the mysql-library-init() function. See , "mysql_library_init()", for more information on the mysql_library_init() function.

Using option files can make it easier to switch between a client/server application and one where MariaDB is embedded. Put common options under the [server] group. These are read by both MariaDB versions. Client/server-specific options should go under the [mysqld] section. Put options specific to the embedded MariaDB server library in the [embedded] section. Options specific to applications go under section labeled [ApplicationName_SERVER]. See , "Using Option Files".

Embedded Server Examples

These two example programs should work without any changes on a Linux or FreeBSD system. For other operating systems, minor changes are needed, mostly with file paths. These examples are designed to give enough details for you to understand the problem, without the clutter that is a necessary part of a real application. The first example is very straightforward. The second example is a little more advanced with some error checking. The first is followed by a command-line entry for compiling the program. The second is followed by a GNUmake file that may be used for compiling instead.

Example 1

test1_libmysqld.c 

#include <stdio.h>
#include <stdlib.h>
#include <stdarg.h>
#include 'mysql.h'
MYSQL *mysql;
MYSQL_RES *results;
MYSQL_ROW record;
static char *server_options[] = \
 { 'mysql_test', '--defaults-file=my.cnf', NULL };
int num_elements = (sizeof(server_options) / sizeof(char *)) - 1;
static char *server_groups[] = { 'libmysqld_server',
 'libmysqld_client', NULL };
int main(void)
{
 mysql_library_init(num_elements, server_options, server_groups);
 mysql = mysql_init(NULL);
 mysql_options(mysql, MYSQL_READ_DEFAULT_GROUP, 'libmysqld_client');
 mysql_options(mysql, MYSQL_OPT_USE_EMBEDDED_CONNECTION, NULL);
 mysql_real_connect(mysql, NULL,NULL,NULL, 'database1', 0,NULL,0);
 mysql_query(mysql, 'SELECT column1, column2 FROM table1');
 results = mysql_store_result(mysql);
 while((record = mysql_fetch_row(results))) {
 printf('%s - %s \n', record[0], record[1]);
 }
 mysql_free_result(results);
 mysql_close(mysql);
 mysql_library_end();
 return 0;
}

Here is the command line for compiling the above program: 

gcc test1_libmysqld.c -o test1_libmysqld -lz \
 `/usr/local/mysql/bin/mysql_config --include --libmysqld-libs`

Example 2

To try the example, create an test2_libmysqld directory at the same level as the MariaDB source directory. Save the test2_libmysqld.c source and the GNUmakefile in the directory, and run GNU make from inside the test2_libmysqld directory.

test2_libmysqld.c 

/*
 * A simple example client, using the embedded MariaDB server library
*/
#include <mysql.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
MYSQL *db_connect(const char *dbname);
void db_disconnect(MYSQL *db);
void db_do_query(MYSQL *db, const char *query);
const char *server_groups[] = {
 'test2_libmysqld_SERVER', 'embedded', 'server', NULL
};
int main(int argc, char **argv)
{
 MYSQL *one, *two;
 /* mysql_library_init() must be called before any other mysql
 * functions.
 *
 * You can use mysql_library_init(0, NULL, NULL), and it
 * initializes the server using groups = {
 * 'server', 'embedded', NULL
 * }.
 *
 * In your $HOME/.my.cnf file, you probably want to put:
[test2_libmysqld_SERVER]
language = /path/to/source/of/mysql/sql/share/english
 * You could, of course, modify argc and argv before passing
 * them to this function. Or you could create new ones in any
 * way you like. But all of the arguments in argv (except for
 * argv[0], which is the program name) should be valid options
 * for the MariaDB server.
 *
 * If you link this client against the normal mysqlclient
 * library, this function is just a stub that does nothing.
 */
 mysql_library_init(argc, argv, (char **)server_groups);
 one = db_connect('test');
 two = db_connect(NULL);
 db_do_query(one, 'SHOW TABLE STATUS');
 db_do_query(two, 'SHOW DATABASES');
 mysql_close(two);
 mysql_close(one);
 /* This must be called after all other mysql functions */
 mysql_library_end();
 exit(EXIT_SUCCESS);
}
static void die(MYSQL *db, char *fmt, ...)
{
 va_list ap;
 va_start(ap, fmt);
 vfprintf(stderr, fmt, ap);
 va_end(ap);
 (void)putc('\n', stderr);
 if (db)
 db_disconnect(db);
 exit(EXIT_FAILURE);
}
MYSQL *
db_connect(const char *dbname)
{
 MYSQL *db = mysql_init(NULL);
 if (!db)
 die(db, 'mysql_init failed: no memory');
 /*
 * Notice that the client and server use separate group names.
 * This is critical, because the server does not accept the
 * client's options, and vice versa.
 */
 mysql_options(db, MYSQL_READ_DEFAULT_GROUP, 'test2_libmysqld_CLIENT');
 if (!mysql_real_connect(db, NULL, NULL, NULL, dbname, 0, NULL, 0))
 die(db, 'mysql_real_connect failed: %s', mysql_error(db));
 return db;
}
void db_disconnect(MYSQL *db)
{
 mysql_close(db);
}
void db_do_query(MYSQL *db, const char *query)
{
 if (mysql_query(db, query) != 0)
 goto err;
 if (mysql_field_count(db) > 0)
 {
 MYSQL_RES *res;
 MYSQL_ROW row, end_row;
 int num_fields;
 if (!(res = mysql_store_result(db)))
 goto err;
 num_fields = mysql_num_fields(res);
 while ((row = mysql_fetch_row(res)))
 {
 (void)fputs('>> ', stdout);
 for (end_row = row + num_fields; row < end_row; ++row)
 (void)printf('%s\t', row ? (char*)*row : 'NULL');
 (void)fputc('\n', stdout);
 }
 (void)fputc('\n', stdout);
 mysql_free_result(res);
 }
 else
 (void)printf('Affected rows: %lld\n', mysql_affected_rows(db));
 return;
err:
 die(db, 'db_do_query failed: %s [%s]', mysql_error(db), query);
}

GNUmakefile 

# This assumes the MariaDB software is installed in /usr/local/mysql inc := /usr/local/mysql/include/mysql lib := /usr/local/mysql/lib
# If you have not installed the MariaDB software yet, try this instead
#inc := $(HOME)/mysql-5.6/include
#lib := $(HOME)/mysql-5.6/libmysqld CC := gcc CPPFLAGS := -I$(inc) -D_THREAD_SAFE -D_REENTRANT CFLAGS := -g -W -Wall LDFLAGS := -static
# You can change -lmysqld to -lmysqlclient to use the
# client/server library LDLIBS = -L$(lib) -lmysqld -lz -lm -ldl -lcrypt ifneq (,$(shell grep FreeBSD /COPYRIGHT 2>/dev/null))
# FreeBSD LDFLAGS += -pthread else
# Assume Linux LDLIBS += -lpthread endif
# This works for simple one-file test programs sources := $(wildcard *.c)
objects := $(patsubst %c,%o,$(sources))
targets := $(basename $(sources))
all: $(targets)
clean:
 rm -f $(targets) $(objects) *.core

Licensing the Embedded Server

We encourage everyone to promote free software by releasing code under the GPL or a compatible license. For those who are not able to do this, another option is to purchase a commercial license for the MariaDB code from Oracle Corporation. For details, please see http://www.mysql.com/company/legal/licensing/.

MySQL C API

C API Data Structures
C API Function Overview
C API Function Descriptions
C API Prepared Statements
C API Prepared Statement Data Structures
C API Prepared Statement Function Overview
C API Prepared Statement Function Descriptions
C API Threaded Function Descriptions
C API Embedded Server Function Descriptions
C API Client Plugin Functions
Common Questions and Problems When Using the C API
Controlling Automatic Reconnection Behavior
C API Support for Multiple Statement Execution
C API Prepared Statement Problems
C API Prepared Statement Handling of Date and Time Values
C API Support for Prepared CALL Statements
Building Client Programs

The C API code is distributed with MySQL. It is included in the mysqlclient library and enables C programs to access a database.

Many of the clients in the MariaDB source distribution are written in C. If you are looking for examples that demonstrate how to use the C API, take a look at these clients. You can find these in the client directory in the MariaDB source distribution.

Most of the other client APIs (all except Connector/J and Connector/Net) use the mysqlclient library to communicate with the MariaDB server. This means that, for example, you can take advantage of many of the same environment variables that are used by other client programs, because they are referenced from the library. See , MySQL Programs, for a list of these variables.

The client has a maximum communication buffer size. The size of the buffer that is allocated initially (16KB) is automatically increased up to the maximum size (the maximum is 16MB). Because buffer sizes are increased only as demand warrants, simply increasing the default maximum limit does not in itself cause more resources to be used. This size check is mostly a check for erroneous statements and communication packets.

The communication buffer must be large enough to contain a single SQL statement (for client-to-server traffic) and one row of returned data (for server-to-client traffic). Each thread's communication buffer is dynamically enlarged to handle any query or row up to the maximum limit. For example, if you have BLOB values that contain up to 16MB of data, you must have a communication buffer limit of at least 16MB (in both server and client). The client's default maximum is 16MB, but the default maximum in the server is 1MB. You can increase this by changing the value of the max_allowed_packet parameter when the server is started. See , "Tuning Server Parameters".

The MariaDB server shrinks each communication buffer to net_buffer_length bytes after each query. For clients, the size of the buffer associated with a connection is not decreased until the connection is closed, at which time client memory is reclaimed.

For programming with threads, see , "How to Write a Threaded Client". For creating a standalone application which includes the 'server' and 'client' in the same program (and does not communicate with an external MariaDB server), see , "libmysqld, the Embedded MariaDB Server Library".Note

If, after an upgrade, you experience problems with compiled client programs, such as Commands out of sync or unexpected core dumps, you probably have used old header or library files when compiling your programs. In this case, check the date for your mysql.h file and libmysqlclient.a library to verify that they are from the new MariaDB distribution. If not, recompile your programs with the new headers and libraries. Recompilation might also be necessary for programs compiled against the shared client library if the library major version number has changed (for example from libmysqlclient.so.15 to libmysqlclient.so.16.

C API Data Structures

This section describes C API data structures other than those used for prepared statements. For information about the latter, see , "C API Prepared Statement Data Structures".

The MYSQL_FIELD structure contains the members described in the following list. The definitions apply primarily for columns of result sets such as those produced by SELECT statements. In MariaDB 5.6, MYSQL_FIELD structures are also used to provide metadata for OUT and INOUT parameters returned from stored procedures executed using prepared CALL statements. For such parameters, some of the structure members have a meaning different from the meaning for column values.

C API Function Overview

The functions available in the C API are summarized here and described in greater detail in a later section. See , "C API Function Descriptions".

Table 20.7. C API Function Names and Descriptions

Function Description
my_init() Initialize global variables, and thread handler in thread-safe programs
mysql_affected_rows() Returns the number of rows changed/deleted/inserted by the last UPDATE, DELETE, or INSERT query
mysql_autocommit() Toggles autocommit mode on/off
mysql_change_user() Changes user and database on an open connection
mysql_character_set_name() Return default character set name for current connection
mysql_client_find_plugin() Return pointer to plugin
mysql_client_register_plugin() Register a plugin
mysql_close() Closes a server connection
mysql_commit() Commits the transaction
mysql_connect() Connects to a MariaDB server (this function is deprecated; use mysql_real_connect() instead)
mysql_create_db() Creates a database (this function is deprecated; use the SQL statement CREATE DATABASE instead)
mysql_data_seek() Seeks to an arbitrary row number in a query result set
mysql_debug() Does a DBUG_PUSH with the given string
mysql_drop_db() Drops a database (this function is deprecated; use the SQL statement DROP DATABASE instead)
mysql_dump_debug_info() Makes the server write debug information to the log
mysql_eof() Determines whether the last row of a result set has been read (this function is deprecated; mysql_errno() or mysql_error() may be used instead)
mysql_errno() Returns the error number for the most recently invoked MariaDB function
mysql_error() Returns the error message for the most recently invoked MariaDB function
mysql_escape_string() Escapes special characters in a string for use in an SQL statement
mysql_fetch_field() Returns the type of the next table field
mysql_fetch_field_direct() Returns the type of a table field, given a field number
mysql_fetch_fields() Returns an array of all field structures
mysql_fetch_lengths() Returns the lengths of all columns in the current row
mysql_fetch_row() Fetches the next row from the result set
mysql_field_count() Returns the number of result columns for the most recent statement
mysql_field_seek() Puts the column cursor on a specified column
mysql_field_tell() Returns the position of the field cursor used for the last mysql_fetch_field()
mysql_free_result() Frees memory used by a result set
mysql_get_character_set_info() Return information about default character set
mysql_get_client_info() Returns client version information as a string
mysql_get_client_version() Returns client version information as an integer
mysql_get_host_info() Returns a string describing the connection
mysql_get_proto_info() Returns the protocol version used by the connection
mysql_get_server_info() Returns the server version number
mysql_get_server_version() Returns version number of server as an integer
mysql_get_ssl_cipher() Return current SSL cipher
mysql_hex_string() Encode string in hexadecimal format
mysql_info() Returns information about the most recently executed query
mysql_init() Gets or initializes a MariaDB structure
mysql_insert_id() Returns the ID generated for an AUTO_INCREMENT column by the previous query
mysql_kill() Kills a given thread
mysql_library_end() Finalize the MariaDB C API library
mysql_library_init() Initialize the MariaDB C API library
mysql_list_dbs() Returns database names matching a simple regular expression
mysql_list_fields() Returns field names matching a simple regular expression
mysql_list_processes() Returns a list of the current server threads
mysql_list_tables() Returns table names matching a simple regular expression
mysql_load_plugin() Load a plugin
mysql_load_plugin_v() Load a plugin
mysql_more_results() Checks whether any more results exist
mysql_next_result() Returns/initiates the next result in multiple-result executions
mysql_num_fields() Returns the number of columns in a result set
mysql_num_rows() Returns the number of rows in a result set
mysql_options() Sets connect options for mysql_real_connect()
mysql_ping() Checks whether the connection to the server is working, reconnecting as necessary
mysql_plugin_options() Set a plugin option
mysql_query() Executes an SQL query specified as a null-terminated string
mysql_real_connect() Connects to a MariaDB server
mysql_real_escape_string() Escapes special characters in a string for use in an SQL statement, taking into account the current character set of the connection
mysql_real_query() Executes an SQL query specified as a counted string
mysql_refresh() Flush or reset tables and caches
mysql_reload() Tells the server to reload the grant tables
mysql_rollback() Rolls back the transaction
mysql_row_seek() Seeks to a row offset in a result set, using value returned from mysql_row_tell()
mysql_row_tell() Returns the row cursor position
mysql_select_db() Selects a database
mysql_server_end() Finalize the MariaDB C API library
mysql_server_init() Initialize the MariaDB C API library
mysql_set_character_set() Set default character set for current connection
mysql_set_local_infile_default() Set the LOAD DATA LOCAL INFILE handler callbacks to their default values
mysql_set_local_infile_handler() Install application-specific LOAD DATA LOCAL INFILE handler callbacks
mysql_set_server_option() Sets an option for the connection (like multi-statements)
mysql_sqlstate() Returns the SQLSTATE error code for the last error
mysql_shutdown() Shuts down the database server
mysql_ssl_set() Prepare to establish SSL connection to server
mysql_stat() Returns the server status as a string
mysql_store_result() Retrieves a complete result set to the client
mysql_thread_end() Finalize thread handler
mysql_thread_id() Returns the current thread ID
mysql_thread_init() Initialize thread handler
mysql_thread_safe() Returns 1 if the clients are compiled as thread-safe
mysql_use_result() Initiates a row-by-row result set retrieval
mysql_warning_count() Returns the warning count for the previous SQL statement

Application programs should use this general outline for interacting with MySQL:

  1. Initialize the MariaDB library by calling mysql_library_init(). This function exists in both the mysqlclient C client library and the mysqld embedded server library, so it is used whether you build a regular client program by linking with the -libmysqlclient flag, or an embedded server application by linking with the -libmysqld flag.

  2. Initialize a connection handler by calling mysql-init() and connect to the server by calling mysql_real_connect().
  3. Issue SQL statements and process their results. (The following discussion provides more information about how to do this.)
  4. Close the connection to the MariaDB server by calling mysql_close().
  5. End use of the MariaDB library by calling mysql_library_end().

The purpose of calling mysql-library-init() and mysql_library_end() is to provide proper initialization and finalization of the MariaDB library. For applications that are linked with the client library, they provide improved memory management. If you don't call mysql_library_end(), a block of memory remains allocated. (This does not increase the amount of memory used by the application, but some memory leak detectors will complain about it.) For applications that are linked with the embedded server, these calls start and stop the server.

In a nonmulti-threaded environment, the call to mysql_library_init() may be omitted, because mysql_init() will invoke it automatically as necessary. However, mysql_library_init() is not thread-safe in a multi-threaded environment, and thus neither is mysql_init(), which calls mysql_library_init(). You must either call mysql_library_init() prior to spawning any threads, or else use a mutex to protect the call, whether you invoke mysql_library_init() or indirectly through mysql_init(). This should be done prior to any other client library call.

To connect to the server, call mysql-init() to initialize a connection handler, then call mysql_real_connect() with that handler (along with other information such as the host name, user name, and password). Upon connection, mysql_real_connect() sets the reconnect flag (part of the MariaDB structure) to a value of 1 in versions of the API older than 5.0.3, or 0 in newer versions. A value of 1 for this flag indicates that if a statement cannot be performed because of a lost connection, to try reconnecting to the server before giving up. You can use the MYSQL_OPT_RECONNECT option to mysql_options() to control reconnection behavior. When you are done with the connection, call mysql_close() to terminate it.

While a connection is active, the client may send SQL statements to the server using mysql_query() or mysql_real_query(). The difference between the two is that mysql_query() expects the query to be specified as a null-terminated string whereas mysql_real_query() expects a counted string. If the string contains binary data (which may include null bytes), you must use mysql_real_query().

For each non-SELECT query (for example, INSERT, UPDATE, DELETE), you can find out how many rows were changed (affected) by calling mysql_affected_rows().

For SELECT queries, you retrieve the selected rows as a result set. (Note that some statements are SELECT-like in that they return rows. These include SHOW, DESCRIBE, and EXPLAIN. Treat these statements the same way as SELECT statements.)

There are two ways for a client to process result sets. One way is to retrieve the entire result set all at once by calling mysql_store_result(). This function acquires from the server all the rows returned by the query and stores them in the client. The second way is for the client to initiate a row-by-row result set retrieval by calling mysql_use_result(). This function initializes the retrieval, but does not actually get any rows from the server.

In both cases, you access rows by calling mysql-fetch-row(). With mysql_store_result(), mysql_fetch_row() accesses rows that have previously been fetched from the server. With mysql-use-result(), mysql_fetch_row() actually retrieves the row from the server. Information about the size of the data in each row is available by calling mysql_fetch_lengths().

After you are done with a result set, call mysql_free_result() to free the memory used for it.

The two retrieval mechanisms are complementary. Choose the approach that is most appropriate for each client application. In practice, clients tend to use mysql_store_result() more commonly.

An advantage of mysql_store_result() is that because the rows have all been fetched to the client, you not only can access rows sequentially, you can move back and forth in the result set using mysql-data-seek() or mysql_row_seek() to change the current row position within the result set. You can also find out how many rows there are by calling mysql_num_rows(). On the other hand, the memory requirements for mysql_store_result() may be very high for large result sets and you are more likely to encounter out-of-memory conditions.

An advantage of mysql_use_result() is that the client requires less memory for the result set because it maintains only one row at a time (and because there is less allocation overhead, mysql_use_result() can be faster). Disadvantages are that you must process each row quickly to avoid tying up the server, you don't have random access to rows within the result set (you can only access rows sequentially), and you don't know how many rows are in the result set until you have retrieved them all. Furthermore, you must retrieve all the rows even if you determine in mid-retrieval that you've found the information you were looking for.

The API makes it possible for clients to respond appropriately to statements (retrieving rows only as necessary) without knowing whether the statement is a SELECT. You can do this by calling mysql-store-result() after each mysql_query() (or mysql_real_query()). If the result set call succeeds, the statement was a SELECT and you can read the rows. If the result set call fails, call mysql_field_count() to determine whether a result was actually to be expected. If mysql_field_count() returns zero, the statement returned no data (indicating that it was an INSERT, UPDATE, DELETE, and so forth), and was not expected to return rows. If mysql_field_count() is nonzero, the statement should have returned rows, but didn't. This indicates that the statement was a SELECT that failed. See the description for mysql_field_count() for an example of how this can be done.

Both mysql-store-result() and mysql_use_result() enable you to obtain information about the fields that make up the result set (the number of fields, their names and types, and so forth). You can access field information sequentially within the row by calling mysql-fetch-field() repeatedly, or by field number within the row by calling mysql_fetch_field_direct(). The current field cursor position may be changed by calling mysql_field_seek(). Setting the field cursor affects subsequent calls to mysql_fetch_field(). You can also get information for fields all at once by calling mysql_fetch_fields().

For detecting and reporting errors, MariaDB provides access to error information by means of the mysql_errno() and mysql_error() functions. These return the error code or error message for the most recently invoked function that can succeed or fail, enabling you to determine when an error occurred and what it was.

C API Function Descriptions

mysql_affected_rows()
mysql_autocommit()
mysql_change_user()
mysql_character_set_name()
mysql_close()
mysql_commit()
mysql_connect()
mysql_create_db()
mysql_data_seek()
mysql_debug()
mysql_drop_db()
mysql_dump_debug_info()
mysql_eof()
mysql_errno()
mysql_error()
mysql_escape_string()
mysql_fetch_field()
mysql_fetch_field_direct()
mysql_fetch_fields()
mysql_fetch_lengths()
mysql_fetch_row()
mysql_field_count()
mysql_field_seek()
mysql_field_tell()
mysql_free_result()
mysql_get_character_set_info()
mysql_get_client_info()
mysql_get_client_version()
mysql_get_host_info()
mysql_get_proto_info()
mysql_get_server_info()
mysql_get_server_version()
mysql_get_ssl_cipher()
mysql_hex_string()
mysql_info()
mysql_init()
mysql_insert_id()
mysql_kill()
mysql_library_end()
mysql_library_init()
mysql_list_dbs()
mysql_list_fields()
mysql_list_processes()
mysql_list_tables()
mysql_more_results()
mysql_next_result()
mysql_num_fields()
mysql_num_rows()
mysql_options()
mysql_ping()
mysql_query()
mysql_real_connect()
mysql_real_escape_string()
mysql_real_query()
mysql_refresh()
mysql_reload()
mysql_rollback()
mysql_row_seek()
mysql_row_tell()
mysql_select_db()
mysql_set_character_set()
mysql_set_local_infile_default()
mysql_set_local_infile_handler()
mysql_set_server_option()
mysql_shutdown()
mysql_sqlstate()
mysql_ssl_set()
mysql_stat()
mysql_store_result()
mysql_thread_id()
mysql_use_result()
mysql_warning_count()

In the descriptions here, a parameter or return value of NULL means NULL in the sense of the C programming language, not a MariaDB NULL value.

Functions that return a value generally return a pointer or an integer. Unless specified otherwise, functions returning a pointer return a non-NULL value to indicate success or a NULL value to indicate an error, and functions returning an integer return zero to indicate success or nonzero to indicate an error. Note that "nonzero" means just that. Unless the function description says otherwise, do not test against a value other than zero: 

if (result) /* correct */
 ... error ...
if (result < 0) /* incorrect */
 ... error ...
if (result == -1) /* incorrect */
 ... error ...

When a function returns an error, the Errors subsection of the function description lists the possible types of errors. You can find out which of these occurred by calling mysql_errno(). A string representation of the error may be obtained by calling mysql_error().

mysql_affected_rows()

my_ulonglong mysql_affected_rows(MYSQL *mysql)

Description

mysql-affected-rows() may be called immediately after executing a statement with mysql_query() or mysql_real_query(). It returns the number of rows changed, deleted, or inserted by the last statement if it was an UPDATE, DELETE, or INSERT. For SELECT statements, mysql-affected-rows() works like mysql_num_rows().

For UPDATE statements, the affected-rows value by default is the number of rows actually changed. If you specify the CLIENT_FOUND_ROWS flag to mysql-real-connect() when connecting to mysqld, the affected-rows value is the number of rows "found"; that is, matched by the WHERE clause.

For REPLACE statements, the affected-rows value is 2 if the new row replaced an old row, because in this case, one row was inserted after the duplicate was deleted.

For INSERT ... ON DUPLICATE KEY UPDATE statements, the affected-rows value is 1 if the row is inserted as a new row and 2 if an existing row is updated.

Following a CALL statement for a stored procedure, mysql_affected_rows() returns the value that it would return for the last statement executed within the procedure, or 0 if that statement would return -1. Within the procedure, you can use ROW_COUNT() at the SQL level to obtain the affected-rows value for individual statements.

In MariaDB 5.6, mysql_affected_rows() returns a meaningful value for a wider range of statements. For details, see the description for ROW-COUNT() in , "Information Functions".

Return Values

An integer greater than zero indicates the number of rows affected or retrieved. Zero indicates that no records were updated for an UPDATE statement, no rows matched the WHERE clause in the query or that no query has yet been executed. -1 indicates that the query returned an error or that, for a SELECT query, mysql_affected_rows() was called prior to calling mysql_store_result().

Because mysql_affected_rows() returns an unsigned value, you can check for -1 by comparing the return value to (my_ulonglong)-1 (or to (my_ulonglong)~0, which is equivalent).

Errors

None.

Example
char *stmt = 'UPDATE products SET cost=cost*1.25
 WHERE group=10';
mysql_query(&mysql,stmt);
printf('%ld products updated',
 (long) mysql_affected_rows(&mysql));

mysql_autocommit()

my_bool mysql_autocommit(MYSQL *mysql, my_bool mode)

Description

Sets autocommit mode on if mode is 1, off if mode is 0.

Return Values

Zero if successful. Nonzero if an error occurred.

Errors

None.

mysql_change_user()

my_bool mysql_change_user(MYSQL *mysql, const char *user, const char *password, const char *db)

Description

Changes the user and causes the database specified by db to become the default (current) database on the connection specified by MariaDB. In subsequent queries, this database is the default for table references that do not include an explicit database specifier.

mysql_change_user() fails if the connected user cannot be authenticated or doesn't have permission to use the database. In this case, the user and database are not changed.

The db parameter may be set to NULL if you don't want to have a default database.

This command resets the state as if one had done a new connect. (See , "Controlling Automatic Reconnection Behavior".) It always performs a ROLLBACK of any active transactions, closes and drops all temporary tables, and unlocks all locked tables. Session system variables are reset to the values of the corresponding global system variables. Prepared statements are released and HANDLER variables are closed. Locks acquired with GET_LOCK() are released. These effects occur even if the user didn't change.

Return Values

Zero for success. Nonzero if an error occurred.

Errors

The same that you can get from mysql_real_connect().

Example
if (mysql_change_user(&mysql, 'user', 'password', 'new_database'))
{
 fprintf(stderr, 'Failed to change user. Error: %s\n',
 mysql_error(&mysql));
}

mysql_character_set_name()

const char *mysql_character_set_name(MYSQL *mysql)

Description

Returns the default character set name for the current connection.

Return Values

The default character set name

Errors

None.

mysql_close()

void mysql_close(MYSQL *mysql)

Description

Closes a previously opened connection. mysql_close() also deallocates the connection handle pointed to by MariaDB if the handle was allocated automatically by mysql-init() or mysql_connect().

Return Values

None.

Errors

None.

mysql_commit()

my_bool mysql_commit(MYSQL *mysql)

Description

Commits the current transaction.

The action of this function is subject to the value of the completion_type system variable. In particular, if the value of completion_type is RELEASE (or 2), the server performs a release after terminating a transaction and closes the client connection. Call mysql_close() from the client program to close the connection from the client side.

Return Values

Zero if successful. Nonzero if an error occurred.

Errors

None.

mysql_connect()

MYSQL *mysql_connect(MYSQL *mysql, const char *host, const char *user, const char *passwd)

Description

This function is deprecated. Use mysql_real_connect() instead.

mysql_connect() attempts to establish a connection to a MariaDB database engine running on host. mysql_connect() must complete successfully before you can execute any of the other API functions, with the exception of mysql_get_client_info().

The meanings of the parameters are the same as for the corresponding parameters for mysql_real_connect() with the difference that the connection parameter may be NULL. In this case, the C API allocates memory for the connection structure automatically and frees it when you call mysql_close(). The disadvantage of this approach is that you can't retrieve an error message if the connection fails. (To get error information from mysql_errno() or mysql_error(), you must provide a valid MariaDB pointer.)

Return Values

Same as for mysql_real_connect().

Errors

Same as for mysql_real_connect().

mysql_create_db()

int mysql_create_db(MYSQL *mysql, const char *db)

Description

Creates the database named by the db parameter.

This function is deprecated. It is preferable to use mysql-query() to issue an SQL CREATE DATABASE statement instead.

Return Values

Zero if the database was created successfully. Nonzero if an error occurred.

Errors
Example
if(mysql_create_db(&mysql, 'my_database'))
{
 fprintf(stderr, 'Failed to create new database. Error: %s\n',
 mysql_error(&mysql));
}

mysql_data_seek()

void mysql_data_seek(MYSQL_RES *result, my_ulonglong offset)

Description

Seeks to an arbitrary row in a query result set. The offset value is a row number. Specify a value in the range from 0 to mysql_num_rows(result)-1.

This function requires that the result set structure contains the entire result of the query, so mysql_data_seek() may be used only in conjunction with mysql-store-result(), not with mysql_use_result().

Return Values

None.

Errors

None.

mysql_debug()

void mysql_debug(const char *debug)

Description

Does a DBUG_PUSH with the given string. mysql_debug() uses the Fred Fish debug library. To use this function, you must compile the client library to support debugging. See MySQL Internals: Porting.

Return Values

None.

Errors

None.

Example

The call shown here causes the client library to generate a trace file in /tmp/client.trace on the client machine: 

mysql_debug('d:t:O,/tmp/client.trace');

mysql_drop_db()

int mysql_drop_db(MYSQL *mysql, const char *db)

Description

Drops the database named by the db parameter.

This function is deprecated. It is preferable to use mysql-query() to issue an SQL DROP DATABASE statement instead.

Return Values

Zero if the database was dropped successfully. Nonzero if an error occurred.

Errors
Example
if(mysql_drop_db(&mysql, 'my_database'))
 fprintf(stderr, 'Failed to drop the database: Error: %s\n',
 mysql_error(&mysql));

mysql_dump_debug_info()

int mysql_dump_debug_info(MYSQL *mysql)

Description

Instructs the server to write some debug information to the log. For this to work, the connected user must have the SUPER privilege.

Return Values

Zero if the command was successful. Nonzero if an error occurred.

Errors

mysql_eof()

my_bool mysql_eof(MYSQL_RES *result)

Description

This function is deprecated. mysql-errno() or mysql_error() may be used instead.

mysql_eof() determines whether the last row of a result set has been read.

If you acquire a result set from a successful call to mysql_store_result(), the client receives the entire set in one operation. In this case, a NULL return from mysql_fetch_row() always means the end of the result set has been reached and it is unnecessary to call mysql-eof(). When used with mysql_store_result(), mysql_eof() always returns true.

On the other hand, if you use mysql_use_result() to initiate a result set retrieval, the rows of the set are obtained from the server one by one as you call mysql_fetch_row() repeatedly. Because an error may occur on the connection during this process, a NULL return value from mysql_fetch_row() does not necessarily mean the end of the result set was reached normally. In this case, you can use mysql-eof() to determine what happened. mysql_eof() returns a nonzero value if the end of the result set was reached and zero if an error occurred.

Historically, mysql-eof() predates the standard MariaDB error functions mysql_errno() and mysql_error(). Because those error functions provide the same information, their use is preferred over mysql_eof(), which is deprecated. (In fact, they provide more information, because mysql_eof() returns only a boolean value whereas the error functions indicate a reason for the error when one occurs.)

Return Values

Zero if no error occurred. Nonzero if the end of the result set has been reached.

Errors

None.

Example

The following example shows how you might use mysql_eof(): 

mysql_query(&mysql,'SELECT * FROM some_table');
result = mysql_use_result(&mysql);
while((row = mysql_fetch_row(result)))
{
 // do something with data
}
if(!mysql_eof(result)) // mysql_fetch_row() failed due to an error
{
 fprintf(stderr, 'Error: %s\n', mysql_error(&mysql));
}

However, you can achieve the same effect with the standard MariaDB error functions: 

mysql_query(&mysql,'SELECT * FROM some_table');
result = mysql_use_result(&mysql);
while((row = mysql_fetch_row(result)))
{
 // do something with data
}
if(mysql_errno(&mysql)) // mysql_fetch_row() failed due to an error
{
 fprintf(stderr, 'Error: %s\n', mysql_error(&mysql));
}

mysql_errno()

unsigned int mysql_errno(MYSQL *mysql)

Description

For the connection specified by MariaDB, mysql_errno() returns the error code for the most recently invoked API function that can succeed or fail. A return value of zero means that no error occurred. Client error message numbers are listed in the MariaDB errmsg.h header file. Server error message numbers are listed in mysqld_error.h. Errors also are listed at Appendix C, Errors, Error Codes, and Common Problems.

Note that some functions like mysql-fetch-row() don't set mysql_errno() if they succeed.

A rule of thumb is that all functions that have to ask the server for information reset mysql_errno() if they succeed.

MySQL-specific error numbers returned by mysql-errno() differ from SQLSTATE values returned by mysql_sqlstate(). For example, the mysql client program displays errors using the following format, where 1146 is the mysql_errno() value and '42S02' is the corresponding mysql_sqlstate() value: 

shell> SELECT * FROM no_such_table;
ERROR 1146 (42S02): Table 'test.no_such_table' doesn't exist
Return Values

An error code value for the last mysql_xxx() call, if it failed. zero means no error occurred.

Errors

None.

mysql_error()

const char *mysql_error(MYSQL *mysql)

Description

For the connection specified by MariaDB, mysql_error() returns a null-terminated string containing the error message for the most recently invoked API function that failed. If a function didn't fail, the return value of mysql_error() may be the previous error or an empty string to indicate no error.

A rule of thumb is that all functions that have to ask the server for information reset mysql_error() if they succeed.

For functions that reset mysql_error(), the following two tests are equivalent: 

if(*mysql_error(&mysql))
{
 // an error occurred
}
if(mysql_error(&mysql)[0])
{
 // an error occurred
}

The language of the client error messages may be changed by recompiling the MariaDB client library. Currently, you can choose error messages in several different languages. See , "Setting the Error Message Language".

Return Values

A null-terminated character string that describes the error. An empty string if no error occurred.

Errors

None.

mysql_escape_string()

Use mysql_real_escape_string() instead!

This function is identical to mysql_real_escape_string() except that mysql_real_escape_string() takes a connection handler as its first argument and escapes the string according to the current character set. mysql_escape_string() does not take a connection argument and does not respect the current character set.

mysql_fetch_field()

MYSQL_FIELD *mysql_fetch_field(MYSQL_RES *result)

Description

Returns the definition of one column of a result set as a MYSQL_FIELD structure. Call this function repeatedly to retrieve information about all columns in the result set. mysql_fetch_field() returns NULL when no more fields are left.

mysql_fetch_field() is reset to return information about the first field each time you execute a new SELECT query. The field returned by mysql_fetch_field() is also affected by calls to mysql_field_seek().

If you've called mysql-query() to perform a SELECT on a table but have not called mysql_store_result(), MariaDB returns the default blob length (8KB) if you call mysql-fetch-field() to ask for the length of a BLOB field. (The 8KB size is chosen because MariaDB doesn't know the maximum length for the BLOB. This should be made configurable sometime.) Once you've retrieved the result set, field->max_length contains the length of the largest value for this column in the specific query.

Return Values

The MYSQL_FIELD structure for the current column. NULL if no columns are left.

Errors

None.

Example
MYSQL_FIELD *field;
while((field = mysql_fetch_field(result)))
{
 printf('field name %s\n', field->name);
}

mysql_fetch_field_direct()

MYSQL_FIELD *mysql_fetch_field_direct(MYSQL_RES *result, unsigned int fieldnr)

Description

Given a field number fieldnr for a column within a result set, returns that column's field definition as a MYSQL_FIELD structure. Use this function to retrieve the definition for an arbitrary column. Specify a value for fieldnr in the range from 0 to mysql_num_fields(result)-1.

Return Values

The MYSQL_FIELD structure for the specified column.

Errors

None.

Example
unsigned int num_fields;
unsigned int i;
MYSQL_FIELD *field;
num_fields = mysql_num_fields(result);
for(i = 0; i < num_fields; i++)
{
 field = mysql_fetch_field_direct(result, i);
 printf('Field %u is %s\n', i, field->name);
}

mysql_fetch_fields()

MYSQL_FIELD *mysql_fetch_fields(MYSQL_RES *result)

Description

Returns an array of all MYSQL_FIELD structures for a result set. Each structure provides the field definition for one column of the result set.

Return Values

An array of MYSQL_FIELD structures for all columns of a result set.

Errors

None.

Example
unsigned int num_fields;
unsigned int i;
MYSQL_FIELD *fields;
num_fields = mysql_num_fields(result);
fields = mysql_fetch_fields(result);
for(i = 0; i < num_fields; i++)
{
 printf('Field %u is %s\n', i, fields[i].name);
}

mysql_fetch_lengths()

unsigned long *mysql_fetch_lengths(MYSQL_RES *result)

Description

Returns the lengths of the columns of the current row within a result set. If you plan to copy field values, this length information is also useful for optimization, because you can avoid calling strlen(). In addition, if the result set contains binary data, you must use this function to determine the size of the data, because strlen() returns incorrect results for any field containing null characters.

The length for empty columns and for columns containing NULL values is zero. To see how to distinguish these two cases, see the description for mysql_fetch_row().

Return Values

An array of unsigned long integers representing the size of each column (not including any terminating null characters). NULL if an error occurred.

Errors

mysql_fetch_lengths() is valid only for the current row of the result set. It returns NULL if you call it before calling mysql_fetch_row() or after retrieving all rows in the result.

Example
MYSQL_ROW row;
unsigned long *lengths;
unsigned int num_fields;
unsigned int i;
row = mysql_fetch_row(result);
if (row)
{
 num_fields = mysql_num_fields(result);
 lengths = mysql_fetch_lengths(result);
 for(i = 0; i < num_fields; i++)
 {
 printf('Column %u is %lu bytes in length.\n',
 i, lengths[i]);
 }
}

mysql_fetch_row()

MYSQL_ROW mysql_fetch_row(MYSQL_RES *result)

Description

Retrieves the next row of a result set. When used after mysql-store-result(), mysql_fetch_row() returns NULL when there are no more rows to retrieve. When used after mysql_use_result(), mysql_fetch_row() returns NULL when there are no more rows to retrieve or if an error occurred.

The number of values in the row is given by mysql_num_fields(result). If row holds the return value from a call to mysql_fetch_row(), pointers to the values are accessed as row[0] to row[mysql_num_fields(result)-1]. NULL values in the row are indicated by NULL pointers.

The lengths of the field values in the row may be obtained by calling mysql_fetch_lengths(). Empty fields and fields containing NULL both have length 0; you can distinguish these by checking the pointer for the field value. If the pointer is NULL, the field is NULL; otherwise, the field is empty.

Return Values

A MYSQL_ROW structure for the next row. NULL if there are no more rows to retrieve or if an error occurred.

Errors

Note that error is not reset between calls to mysql_fetch_row()

Example
MYSQL_ROW row;
unsigned int num_fields;
unsigned int i;
num_fields = mysql_num_fields(result);
while ((row = mysql_fetch_row(result)))
{
 unsigned long *lengths;
 lengths = mysql_fetch_lengths(result);
 for(i = 0; i < num_fields; i++)
 {
 printf('[%.*s] ', (int) lengths[i],
 row[i] ? row[i] : 'NULL');
 }
 printf('\n');
}

mysql_field_count()

unsigned int mysql_field_count(MYSQL *mysql)

Description

Returns the number of columns for the most recent query on the connection.

The normal use of this function is when mysql_store_result() returned NULL (and thus you have no result set pointer). In this case, you can call mysql_field_count() to determine whether mysql_store_result() should have produced a nonempty result. This enables the client program to take proper action without knowing whether the query was a SELECT (or SELECT-like) statement. The example shown here illustrates how this may be done.

See , "Why mysql_store_result() Sometimes Returns NULL After mysql_query() Returns Success".

Return Values

An unsigned integer representing the number of columns in a result set.

Errors

None.

Example
MYSQL_RES *result;
unsigned int num_fields;
unsigned int num_rows;
if (mysql_query(&mysql,query_string))
{
 // error
}
else // query succeeded, process any data returned by it
{
 result = mysql_store_result(&mysql);
 if (result) // there are rows
 {
 num_fields = mysql_num_fields(result);
 // retrieve rows, then call mysql_free_result(result)
 }
 else // mysql_store_result() returned nothing; should it have?
 {
 if(mysql_field_count(&mysql) == 0)
 {
 // query does not return data
 // (it was not a SELECT)
 num_rows = mysql_affected_rows(&mysql);
 }
 else // mysql_store_result() should have returned data
 {
 fprintf(stderr, 'Error: %s\n', mysql_error(&mysql));
 }
 }
}

An alternative is to replace the mysql-field-count(&mysql) call with mysql_errno(&mysql). In this case, you are checking directly for an error from mysql_store_result() rather than inferring from the value of mysql_field_count() whether the statement was a SELECT.

mysql_field_seek()

MYSQL_FIELD_OFFSET mysql_field_seek(MYSQL_RES *result, MYSQL_FIELD_OFFSET offset)

Description

Sets the field cursor to the given offset. The next call to mysql_fetch_field() retrieves the field definition of the column associated with that offset.

To seek to the beginning of a row, pass an offset value of zero.

Return Values

The previous value of the field cursor.

Errors

None.

mysql_field_tell()

MYSQL_FIELD_OFFSET mysql_field_tell(MYSQL_RES *result)

Description

Returns the position of the field cursor used for the last mysql_fetch_field(). This value can be used as an argument to mysql_field_seek().

Return Values

The current offset of the field cursor.

Errors

None.

mysql_free_result()

void mysql_free_result(MYSQL_RES *result)

Description

Frees the memory allocated for a result set by mysql-store-result(), mysql_use_result(), mysql_list_dbs(), and so forth. When you are done with a result set, you must free the memory it uses by calling mysql_free_result().

Do not attempt to access a result set after freeing it.

Return Values

None.

Errors

None.

mysql_get_character_set_info()

void mysql_get_character_set_info(MYSQL *mysql, MY_CHARSET_INFO *cs)

Description

This function provides information about the default client character set. The default character set may be changed with the mysql_set_character_set() function.

Example

This example shows the fields that are available in the MY_CHARSET_INFO structure: 

if (!mysql_set_character_set(&mysql, 'utf8'))
{
 MY_CHARSET_INFO cs;
 mysql_get_character_set_info(&mysql, &cs);
 printf('character set information:\n');
 printf('character set+collation number: %d\n', cs.number);
 printf('character set name: %s\n', cs.name);
 printf('collation name: %s\n', cs.csname);
 printf('comment: %s\n', cs.comment);
 printf('directory: %s\n', cs.dir);
 printf('multi byte character min. length: %d\n', cs.mbminlen);
 printf('multi byte character max. length: %d\n', cs.mbmaxlen);
}

mysql_get_client_info()

const char *mysql_get_client_info(void)

Description

Returns a string that represents the client library version.

Return Values

A character string that represents the MariaDB client library version.

Errors

None.

mysql_get_client_version()

unsigned long mysql_get_client_version(void)

Description

Returns an integer that represents the client library version. The value has the format XYYZZ where X is the major version, YY is the release level, and ZZ is the version number within the release level. For example, a value of 40102 represents a client library version of 4.1.2.

Return Values

An integer that represents the MariaDB client library version.

Errors

None.

mysql_get_host_info()

const char *mysql_get_host_info(MYSQL *mysql)

Description

Returns a string describing the type of connection in use, including the server host name.

Return Values

A character string representing the server host name and the connection type.

Errors

None.

mysql_get_proto_info()

unsigned int mysql_get_proto_info(MYSQL *mysql)

Description

Returns the protocol version used by current connection.

Return Values

An unsigned integer representing the protocol version used by the current connection.

Errors

None.

mysql_get_server_info()

const char *mysql_get_server_info(MYSQL *mysql)

Description

Returns a string that represents the server version number.

Return Values

A character string that represents the server version number.

Errors

None.

mysql_get_server_version()

unsigned long mysql_get_server_version(MYSQL *mysql)

Description

Returns the version number of the server as an integer.

Return Values

A number that represents the MariaDB server version in this format: 

major_version*10000 + minor_version *100 + sub_version

For example, 5.1.5 is returned as 50105.

This function is useful in client programs for quickly determining whether some version-specific server capability exists.

Errors

None.

mysql_get_ssl_cipher()

const char *mysql_get_ssl_cipher(MYSQL *mysql)

Description

mysql_get_ssl_cipher() returns the SSL cipher used for the given connection to the server. MariaDB is the connection handler returned from mysql_init().

Return Values

A string naming the SSL cipher used for the connection, or NULL if no cipher is being used.

mysql_hex_string()

unsigned long mysql_hex_string(char *to, const char *from, unsigned long length)

Description

This function is used to create a legal SQL string that you can use in an SQL statement. See , "String Literals".

The string in from is encoded to hexadecimal format, with each character encoded as two hexadecimal digits. The result is placed in to and a terminating null byte is appended.

The string pointed to by from must be length bytes long. You must allocate the to buffer to be at least length*2+1 bytes long. When mysql_hex_string() returns, the contents of to is a null-terminated string. The return value is the length of the encoded string, not including the terminating null character.

The return value can be placed into an SQL statement using either 0xvalue or X'value' format. However, the return value does not include the 0x or X'...'. The caller must supply whichever of those is desired.

Example
char query[1000],*end;
end = strmov(query,'INSERT INTO test_table values(');
end = strmov(end,'0x');
end += mysql_hex_string(end,'What is this',12);
end = strmov(end,',0x');
end += mysql_hex_string(end,'binary data: \0\r\n',16);
*end++ = ')';
if (mysql_real_query(&mysql,query,(unsigned int) (end - query)))
{
 fprintf(stderr, 'Failed to insert row, Error: %s\n',
 mysql_error(&mysql));
}

The strmov() function used in the example is included in the mysqlclient library and works like strcpy() but returns a pointer to the terminating null of the first parameter.

Return Values

The length of the value placed into to, not including the terminating null character.

Errors

None.

mysql_info()

const char *mysql_info(MYSQL *mysql)

Description

Retrieves a string providing information about the most recently executed statement, but only for the statements listed here. For other statements, mysql_info() returns NULL. The format of the string varies depending on the type of statement, as described here. The numbers are illustrative only; the string contains values appropriate for the statement.

Note that mysql-info() returns a non-NULL value for INSERT ... VALUES only for the multiple-row form of the statement (that is, only if multiple value lists are specified).

Return Values

A character string representing additional information about the most recently executed statement. NULL if no information is available for the statement.

Errors

None.

mysql_init()

MYSQL *mysql_init(MYSQL *mysql)

Description

Allocates or initializes a MariaDB object suitable for mysql_real_connect(). If MariaDB is a NULL pointer, the function allocates, initializes, and returns a new object. Otherwise, the object is initialized and the address of the object is returned. If mysql_init() allocates a new object, it is freed when mysql_close() is called to close the connection.

Return Values

An initialized MYSQL* handle. NULL if there was insufficient memory to allocate a new object.

Errors

In case of insufficient memory, NULL is returned.

mysql_insert_id()

my_ulonglong mysql_insert_id(MYSQL *mysql)

Description

Returns the value generated for an AUTO_INCREMENT column by the previous INSERT or UPDATE statement. Use this function after you have performed an INSERT statement into a table that contains an AUTO_INCREMENT field, or have used INSERT or UPDATE to set a column value with LAST_INSERT_ID(expr).

The return value of mysql_insert_id() is always zero unless explicitly updated under one of the following conditions:

The return value of mysql_insert_id() can be simplified to the following sequence:

  1. If there is an AUTO_INCREMENT column, and an automatically generated value was successfully inserted, return the first such value.
  2. If LAST_INSERT_ID(expr) occurred in the statement, return expr, even if there was an AUTO_INCREMENT column in the affected table.
  3. The return value varies depending on the statement used. When called after an INSERT statement:
    • If there is an AUTO_INCREMENT column in the table, and there were some explicit values for this column that were successfully inserted into the table, return the last of the explicit values.

    When called after an INSERT ... ON DUPLICATE KEY UPDATE statement:

    • If there is an AUTO_INCREMENT column in the table and there were some explicit successfully inserted values, or some updated rows, return the last of the inserted or updated values.

mysql_insert_id() returns 0 if the previous statement does not use an AUTO_INCREMENT value. If you need to save the value for later, be sure to call mysql_insert_id() immediately after the statement that generates the value.

The value of mysql_insert_id() is affected only by statements issued within the current client connection. It is not affected by statements issued by other clients.

The LAST_INSERT_ID() SQL function will contain the value of the first automatically generated value that was successfully inserted. LAST_INSERT_ID() is not reset between statements because the value of that function is maintained in the server. Another difference from mysql_insert_id() is that LAST_INSERT_ID() is not updated if you set an AUTO_INCREMENT column to a specific nonspecial value. See , "Information Functions".

mysql-insert-id() returns 0 following a CALL statement for a stored procedure that generates an AUTO_INCREMENT value because in this case mysql_insert_id() applies to CALL and not the statement within the procedure. Within the procedure, you can use LAST_INSERT_ID() at the SQL level to obtain the AUTO_INCREMENT value.

The reason for the differences between LAST-INSERT-ID() and mysql_insert_id() is that LAST-INSERT-ID() is made easy to use in scripts while mysql_insert_id() tries to provide more exact information about what happens to the AUTO_INCREMENT column.

Return Values

Described in the preceding discussion.

Errors

None.

mysql_kill()

int mysql_kill(MYSQL *mysql, unsigned long pid)

Description

Asks the server to kill the thread specified by pid.

This function is deprecated. It is preferable to use mysql-query() to issue an SQL KILL statement instead.

Return Values

Zero for success. Nonzero if an error occurred.

Errors

mysql_library_end()

void mysql_library_end(void)

Description

This function finalizes the MariaDB library. Call it when you are done using the library (for example, after disconnecting from the server). The action taken by the call depends on whether your application is linked to the MariaDB client library or the MariaDB embedded server library. For a client program linked against the libmysqlclient library by using the -lmysqlclient flag, mysql_library_end() performs some memory management to clean up. For an embedded server application linked against the libmysqld library by using the -lmysqld flag, mysql_library_end() shuts down the embedded server and then cleans up.

For usage information, see , "C API Function Overview", and , "mysql_library_init()".

mysql_library_init()

int mysql_library_init(int argc, char **argv, char **groups)

Description

Call this function to initialize the MariaDB library before you call any other MariaDB function, whether your application is a regular client program or uses the embedded server. If the application uses the embedded server, this call starts the server and initializes any subsystems (mysys, InnoDB, and so forth) that the server uses.

After your application is done using the MariaDB library, call mysql_library_end() to clean up. See , "mysql_library_end()".

The choice of whether the application operates as a regular client or uses the embedded server depends on whether you use the libmysqlclient or libmysqld library at link time to produce the final executable. For additional information, see , "C API Function Overview".

In a nonmulti-threaded environment, the call to mysql_library_init() may be omitted, because mysql_init() will invoke it automatically as necessary. However, mysql_library_init() is not thread-safe in a multi-threaded environment, and thus neither is mysql_init(), which calls mysql_library_init(). You must either call mysql_library_init() prior to spawning any threads, or else use a mutex to protect the call, whether you invoke mysql_library_init() or indirectly through mysql_init(). Do this prior to any other client library call.

The argc and argv arguments are analogous to the arguments to main(), and enable passing of options to the embedded server. For convenience, argc may be 0 (zero) if there are no command-line arguments for the server. This is the usual case for applications intended for use only as regular (nonembedded) clients, and the call typically is written as mysql_library_init(0, NULL, NULL). 

#include <mysql.h>
#include <stdlib.h>
int main(void) {
 if (mysql_library_init(0, NULL, NULL)) {
 fprintf(stderr, 'could not initialize MariaDB library\n');
 exit(1);
 }
 /* Use any MariaDB API functions here */
 mysql_library_end();
 return EXIT_SUCCESS;
}

When arguments are to be passed (argc is greater than 0), the first element of argv is ignored (it typically contains the program name). mysql_library_init() makes a copy of the arguments so it is safe to destroy argv or groups after the call.

For embedded applications, if you want to connect to an external server without starting the embedded server, you have to specify a negative value for argc.

The groups argument is an array of strings that indicate the groups in option files from which to read options. See , "Using Option Files". Make the final entry in the array NULL. For convenience, if the groups argument itself is NULL, the [server] and [embedded] groups are used by default. 

#include <mysql.h>
#include <stdlib.h>
static char *server_args[] = {
 'this_program', /* this string is not used */
 '--datadir=.',
 '--key_buffer_size=32M'
};
static char *server_groups[] = {
 'embedded',
 'server',
 'this_program_SERVER',
 (char *)NULL
};
int main(void) {
 if (mysql_library_init(sizeof(server_args) / sizeof(char *),
 server_args, server_groups)) {
 fprintf(stderr, 'could not initialize MariaDB library\n');
 exit(1);
 }
 /* Use any MariaDB API functions here */
 mysql_library_end();
 return EXIT_SUCCESS;
}
Return Values

Zero if successful. Nonzero if an error occurred.

mysql_list_dbs()

MYSQL_RES *mysql_list_dbs(MYSQL *mysql, const char *wild)

Description

Returns a result set consisting of database names on the server that match the simple regular expression specified by the wild parameter. wild may contain the wildcard characters "%" or "_", or may be a NULL pointer to match all databases. Calling mysql_list_dbs() is similar to executing the query SHOW DATABASES [LIKE wild].

You must free the result set with mysql_free_result().

Return Values

A MYSQL_RES result set for success. NULL if an error occurred.

Errors

mysql_list_fields()

MYSQL_RES *mysql_list_fields(MYSQL *mysql, const char *table, const char *wild)

Description

Returns a result set consisting of field names in the given table that match the simple regular expression specified by the wild parameter. wild may contain the wildcard characters "%" or "_", or may be a NULL pointer to match all fields. Calling mysql_list_fields() is similar to executing the query SHOW COLUMNS FROM tbl_name [LIKE wild].

It is preferable to use SHOW COLUMNS FROM tbl_name instead of mysql_list_fields().

You must free the result set with mysql_free_result().

Return Values

A MYSQL_RES result set for success. NULL if an error occurred.

Errors

mysql_list_processes()

MYSQL_RES *mysql_list_processes(MYSQL *mysql)

Description

Returns a result set describing the current server threads. This is the same kind of information as that reported by mysqladmin processlist or a SHOW PROCESSLIST query.

You must free the result set with mysql_free_result().

Return Values

A MYSQL_RES result set for success. NULL if an error occurred.

Errors

mysql_list_tables()

MYSQL_RES *mysql_list_tables(MYSQL *mysql, const char *wild)

Description

Returns a result set consisting of table names in the current database that match the simple regular expression specified by the wild parameter. wild may contain the wildcard characters "%" or "_", or may be a NULL pointer to match all tables. Calling mysql_list_tables() is similar to executing the query SHOW TABLES [LIKE wild].

You must free the result set with mysql_free_result().

Return Values

A MYSQL_RES result set for success. NULL if an error occurred.

Errors

mysql_more_results()

my_bool mysql_more_results(MYSQL *mysql)

Description

This function is used when you execute multiple statements specified as a single statement string, or when you execute CALL statements, which can return multiple result sets.

mysql_more_results() true if more results exist from the currently executed statement, in which case the application must call mysql_next_result() to fetch the results.

Return Values

TRUE (1) if more results exist. FALSE (0) if no more results exist.

In most cases, you can call mysql_next_result() instead to test whether more results exist and initiate retrieval if so.

See , "C API Support for Multiple Statement Execution", and , "mysql_next_result()".

Errors

None.

mysql_next_result()

int mysql_next_result(MYSQL *mysql)

Description

This function is used when you execute multiple statements specified as a single statement string, or when you use CALL statements to execute stored procedures, which can return multiple result sets.

mysql_next_result() reads the next statement result and returns a status to indicate whether more results exist. If mysql_next_result() returns an error, there are no more results.

Before each call to mysql-next-result(), you must call mysql_free_result() for the current statement if it is a statement that returned a result set (rather than just a result status).

After calling mysql_next_result() the state of the connection is as if you had called mysql_real_query() or mysql_query() for the next statement. This means that you can call mysql_store_result(), mysql_warning_count(), mysql_affected_rows(), and so forth.

If your program uses CALL statements to execute stored procedures, the CLIENT_MULTI_RESULTS flag must be enabled. This is because each CALL returns a result to indicate the call status, in addition to any result sets that might be returned by statements executed within the procedure. Because CALL can return multiple results, process them using a loop that calls mysql_next_result() to determine whether there are more results.

CLIENT_MULTI_RESULTS can be enabled when you call mysql_real_connect(), either explicitly by passing the CLIENT_MULTI_RESULTS flag itself, or implicitly by passing CLIENT_MULTI_STATEMENTS (which also enables CLIENT_MULTI_RESULTS). In MariaDB 5.6, CLIENT_MULTI_RESULTS is enabled by default.

It is also possible to test whether there are more results by calling mysql_more_results(). However, this function does not change the connection state, so if it returns true, you must still call mysql_next_result() to advance to the next result.

For an example that shows how to use mysql-next-result(), see , "C API Support for Multiple Statement Execution".

Return Values
Return Value Description
0 Successful and there are more results
-1 Successful and there are no more results
>0 An error occurred
Errors

mysql_num_fields()

unsigned int mysql_num_fields(MYSQL_RES *result)

To pass a MYSQL* argument instead, use unsigned int mysql_field_count(MYSQL *mysql).

Description

Returns the number of columns in a result set.

Note that you can get the number of columns either from a pointer to a result set or to a connection handle. You would use the connection handle if mysql_store_result() or mysql_use_result() returned NULL (and thus you have no result set pointer). In this case, you can call mysql-field-count() to determine whether mysql_store_result() should have produced a nonempty result. This enables the client program to take proper action without knowing whether the query was a SELECT (or SELECT-like) statement. The example shown here illustrates how this may be done.

See , "Why mysql_store_result() Sometimes Returns NULL After mysql_query() Returns Success".

Return Values

An unsigned integer representing the number of columns in a result set.

Errors

None.

Example
MYSQL_RES *result;
unsigned int num_fields;
unsigned int num_rows;
if (mysql_query(&mysql,query_string))
{
 // error
}
else // query succeeded, process any data returned by it
{
 result = mysql_store_result(&mysql);
 if (result) // there are rows
 {
 num_fields = mysql_num_fields(result);
 // retrieve rows, then call mysql_free_result(result)
 }
 else // mysql_store_result() returned nothing; should it have?
 {
 if (mysql_errno(&mysql))
 {
 fprintf(stderr, 'Error: %s\n', mysql_error(&mysql));
 }
 else if (mysql_field_count(&mysql) == 0)
 {
 // query does not return data
 // (it was not a SELECT)
 num_rows = mysql_affected_rows(&mysql);
 }
 }
}

An alternative (if you know that your query should have returned a result set) is to replace the mysql_errno(&mysql) call with a check whether mysql_field_count(&mysql) returns 0. This happens only if something went wrong.

mysql_num_rows()

my_ulonglong mysql_num_rows(MYSQL_RES *result)

Description

Returns the number of rows in the result set.

The use of mysql-num-rows() depends on whether you use mysql_store_result() or mysql_use_result() to return the result set. If you use mysql-store-result(), mysql_num_rows() may be called immediately. If you use mysql_use_result(), mysql_num_rows() does not return the correct value until all the rows in the result set have been retrieved.

mysql-num-rows() is intended for use with statements that return a result set, such as SELECT. For statements such as INSERT, UPDATE, or DELETE, the number of affected rows can be obtained with mysql_affected_rows().

Return Values

The number of rows in the result set.

Errors

None.

mysql_options()

int mysql_options(MYSQL *mysql, enum mysql_option option, const void *arg)

Description

Can be used to set extra connect options and affect behavior for a connection. This function may be called multiple times to set several options.

Call mysql-options() after mysql_init() and before mysql-connect() or mysql_real_connect().

The option argument is the option that you want to set; the arg argument is the value for the option. If the option is an integer, specify a pointer to the value of the integer as the arg argument.

The following list describes the possible options, their effect, and how arg is used for each option. Several of the options apply only when the application is linked against the libmysqld embedded server library and are unused for applications linked against the libmysql client library. For option descriptions that indicate arg is unused, its value is irrelevant; it is conventional to pass 0.

The client group is always read if you use MYSQL_READ_DEFAULT_FILE or MYSQL_READ_DEFAULT_GROUP.

The specified group in the option file may contain the following options.

Option Description
character-sets-dir=path The directory where character sets are installed.
compress Use the compressed client/server protocol.
connect-timeout=seconds Connect timeout in seconds. On Linux this timeout is also used for waiting for the first answer from the server.
database=db_name Connect to this database if no database was specified in the connect command.
debug Debug options.
default-character-set=charset_name The default character set to use.
disable-local-infile Disable use of LOAD DATA LOCAL.
host=host_name Default host name.
init-command=stmt Statement to execute when connecting to MariaDB server. Automatically re-executed if reconnection occurs.
interactive-timeout=seconds Same as specifying CLIENT_INTERACTIVE to mysql_real_connect(). See , "mysql_real_connect()".
local-infile[={0|1}] If no argument or nonzero argument, enable use of LOAD DATA LOCAL; otherwise disable.
max_allowed_packet=bytes Maximum size of packet that client can read from server.
multi-queries, multi-results Enable multiple result sets from multiple-statement executions or stored procedures.
multi-statements Enable the client to send multiple statements in a single string (separated by ";").
password=password Default password.
pipe Use named pipes to connect to a MariaDB server on Windows.
port=port_num Default port number.
protocol={TCP|SOCKET|PIPE|MEMORY} The protocol to use when connecting to the server.
return-found-rows Tell mysql-info() to return found rows instead of updated rows when using UPDATE.
shared-memory-base-name=name Shared-memory name to use to connect to server.
socket=path Default socket file.
ssl-ca=file_name Certificate Authority file.
ssl-capath=path Certificate Authority directory.
ssl-cert=file_name Certificate file.
ssl-cipher=cipher_list Permissible SSL ciphers.
ssl-key=file_name Key file.
timeout=seconds Like connect-timeout.
user Default user.

timeout has been replaced by connect-timeout, but timeout is still supported in MariaDB 5.6 for backward compatibility.

For more information about option files, see , "Using Option Files".

Return Values

Zero for success. Nonzero if you specify an unknown option.

Example

The following mysql_options() calls request the use of compression in the client/server protocol, cause options to be read from the [odbc] group of option files, and disable transaction autocommit mode: 

MYSQL mysql;
mysql_init(&mysql);
mysql_options(&mysql,MYSQL_OPT_COMPRESS,0);
mysql_options(&mysql,MYSQL_READ_DEFAULT_GROUP,'odbc');
mysql_options(&mysql,MYSQL_INIT_COMMAND,'SET autocommit=0');
if (!mysql_real_connect(&mysql,'host','user','passwd','database',0,NULL,0))
{
 fprintf(stderr, 'Failed to connect to database: Error: %s\n',
 mysql_error(&mysql));
}

This code requests that the client use the compressed client/server protocol and read the additional options from the odbc section in the my.cnf file.

mysql_ping()

int mysql_ping(MYSQL *mysql)

Description

Checks whether the connection to the server is working. If the connection has gone down and auto-reconnect is enabled an attempt to reconnect is made. If the connection is down and auto-reconnect is disabled, mysql_ping() returns an error.

Auto-reconnect is disabled by default. To enable it, call mysql_options() with the MYSQL_OPT_RECONNECT option. For details, see , "mysql_options()".

mysql_ping() can be used by clients that remain idle for a long while, to check whether the server has closed the connection and reconnect if necessary.

If mysql_ping()) does cause a reconnect, there is no explicit indication of it. To determine whether a reconnect occurs, call mysql_thread_id() to get the original connection identifier before calling mysql_ping(), then call mysql_thread_id() again to see whether the identifier has changed.

If reconnect occurs, some characteristics of the connection will have been reset. For details about these characteristics, see , "Controlling Automatic Reconnection Behavior".

Return Values

Zero if the connection to the server is active. Nonzero if an error occurred. A nonzero return does not indicate whether the MariaDB server itself is down; the connection might be broken for other reasons such as network problems.

Errors

mysql_query()

int mysql_query(MYSQL *mysql, const char *stmt_str)

Description

Executes the SQL statement pointed to by the null-terminated string stmt_str. Normally, the string must consist of a single SQL statement without a terminating semicolon (";") or \g. If multiple-statement execution has been enabled, the string can contain several statements separated by semicolons. See , "C API Support for Multiple Statement Execution".

mysql-query() cannot be used for statements that contain binary data; you must use mysql_real_query() instead. (Binary data may contain the "\0" character, which mysql_query() interprets as the end of the statement string.)

If you want to know whether the statement returns a result set, you can use mysql_field_count() to check for this. See , "mysql_field_count()".

Return Values

Zero if the statement was successful. Nonzero if an error occurred.

Errors

mysql_real_connect()

MYSQL *mysql_real_connect(MYSQL *mysql, const char *host, const char *user, const char *passwd, const char *db, unsigned int port, const char *unix_socket, unsigned long client_flag)

Description

mysql_real_connect() attempts to establish a connection to a MariaDB database engine running on host. mysql_real_connect() must complete successfully before you can execute any other API functions that require a valid MariaDB connection handle structure.

The parameters are specified as follows:

If your program uses CALL statements to execute stored procedures, the CLIENT_MULTI_RESULTS flag must be enabled. This is because each CALL returns a result to indicate the call status, in addition to any result sets that might be returned by statements executed within the procedure. Because CALL can return multiple results, process them using a loop that calls mysql_next_result() to determine whether there are more results.

CLIENT_MULTI_RESULTS can be enabled when you call mysql_real_connect(), either explicitly by passing the CLIENT_MULTI_RESULTS flag itself, or implicitly by passing CLIENT_MULTI_STATEMENTS (which also enables CLIENT_MULTI_RESULTS). In MariaDB 5.6, CLIENT_MULTI_RESULTS is enabled by default.

If you enable CLIENT_MULTI_STATEMENTS or CLIENT_MULTI_RESULTS, process the result for every call to mysql_query() or mysql-real-query() by using a loop that calls mysql_next_result() to determine whether there are more results. For an example, see , "C API Support for Multiple Statement Execution".

For some parameters, it is possible to have the value taken from an option file rather than from an explicit value in the mysql_real_connect() call. To do this, call mysql_options() with the MYSQL_READ_DEFAULT_FILE or MYSQL_READ_DEFAULT_GROUP option before calling mysql_real_connect(). Then, in the mysql_real_connect() call, specify the "no-value" value for each parameter to be read from an option file:

If no value is found in an option file for a parameter, its default value is used as indicated in the descriptions given earlier in this section.

Return Values

A MYSQL* connection handle if the connection was successful, NULL if the connection was unsuccessful. For a successful connection, the return value is the same as the value of the first parameter.

Errors
Example
MYSQL mysql;
mysql_init(&mysql);
mysql_options(&mysql,MYSQL_READ_DEFAULT_GROUP,'your_prog_name');
if (!mysql_real_connect(&mysql,'host','user','passwd','database',0,NULL,0))
{
 fprintf(stderr, 'Failed to connect to database: Error: %s\n',
 mysql_error(&mysql));
}

By using mysql_options() the MariaDB library reads the [client] and [your_prog_name] sections in the my.cnf file which ensures that your program works, even if someone has set up MariaDB in some nonstandard way.

Note that upon connection, mysql_real_connect() sets the reconnect flag (part of the MariaDB structure) to a value of 1 in versions of the API older than 5.0.3, or 0 in newer versions. A value of 1 for this flag indicates that if a statement cannot be performed because of a lost connection, to try reconnecting to the server before giving up. You can use the MYSQL_OPT_RECONNECT option to mysql_options() to control reconnection behavior.

mysql_real_escape_string()

unsigned long mysql_real_escape_string(MYSQL *mysql, char *to, const char *from, unsigned long length)

Note that MariaDB must be a valid, open connection. This is needed because the escaping depends on the character set in use by the server.

Description

This function is used to create a legal SQL string that you can use in an SQL statement. See , "String Literals".

The string in from is encoded to an escaped SQL string, taking into account the current character set of the connection. The result is placed in to and a terminating null byte is appended. Characters encoded are "\", "'", "'", NUL (ASCII 0), "\n", "\r", and Control+Z. Strictly speaking, MariaDB requires only that backslash and the quote character used to quote the string in the query be escaped. mysql_real_escape_string() quotes the other characters to make them easier to read in log files. For comparison, see the quoting rules for literal strings and the QUOTE() SQL function in , "String Literals", and , "String Functions".

The string pointed to by from must be length bytes long. You must allocate the to buffer to be at least length*2+1 bytes long. (In the worst case, each character may need to be encoded as using two bytes, and you need room for the terminating null byte.) When mysql_real_escape_string() returns, the contents of to is a null-terminated string. The return value is the length of the encoded string, not including the terminating null character.

If you need to change the character set of the connection, use the mysql_set_character_set() function rather than executing a SET NAMES (or SET CHARACTER SET) statement. mysql_set_character_set() works like SET NAMES but also affects the character set used by mysql_real_escape_string(), which SET NAMES does not.

Example
char query[1000],*end;
end = strmov(query,'INSERT INTO test_table values(');
*end++ = '\'';
end += mysql_real_escape_string(&mysql, end,'What is this',12);
*end++ = '\'';
*end++ = ',';
*end++ = '\'';
end += mysql_real_escape_string(&mysql, end,'binary data: \0\r\n',16);
*end++ = '\'';
*end++ = ')';
if (mysql_real_query(&mysql,query,(unsigned int) (end - query)))
{
 fprintf(stderr, 'Failed to insert row, Error: %s\n',
 mysql_error(&mysql));
}

The strmov() function used in the example is included in the mysqlclient library and works like strcpy() but returns a pointer to the terminating null of the first parameter.

Return Values

The length of the value placed into to, not including the terminating null character.

Errors

None.

mysql_real_query()

int mysql_real_query(MYSQL *mysql, const char *stmt_str, unsigned long length)

Description

Executes the SQL statement pointed to by stmt_str, a string length bytes long. Normally, the string must consist of a single SQL statement without a terminating semicolon (";") or \g. If multiple-statement execution has been enabled, the string can contain several statements separated by semicolons. See , "C API Support for Multiple Statement Execution".

mysql-query() cannot be used for statements that contain binary data; you must use mysql_real_query() instead. (Binary data may contain the "\0" character, which mysql_query() interprets as the end of the statement string.) In addition, mysql_real_query() is faster than mysql_query() because it does not call strlen() on the statement string.

If you want to know whether the statement returns a result set, you can use mysql_field_count() to check for this. See , "mysql_field_count()".

Return Values

Zero if the statement was successful. Nonzero if an error occurred.

Errors

mysql_refresh()

int mysql_refresh(MYSQL *mysql, unsigned int options)

Description

This function flushes tables or caches, or resets replication server information. The connected user must have the RELOAD privilege.

The options argument is a bit mask composed from any combination of the following values. Multiple values can be OR'ed together to perform multiple operations with a single call.

Return Values

Zero for success. Nonzero if an error occurred.

Errors

mysql_reload()

int mysql_reload(MYSQL *mysql)

Description

Asks the MariaDB server to reload the grant tables. The connected user must have the RELOAD privilege.

This function is deprecated. It is preferable to use mysql-query() to issue an SQL FLUSH PRIVILEGES statement instead.

Return Values

Zero for success. Nonzero if an error occurred.

Errors

mysql_rollback()

my_bool mysql_rollback(MYSQL *mysql)

Description

Rolls back the current transaction.

The action of this function is subject to the value of the completion_type system variable. In particular, if the value of completion_type is RELEASE (or 2), the server performs a release after terminating a transaction and closes the client connection. Call mysql_close() from the client program to close the connection from the client side.

Return Values

Zero if successful. Nonzero if an error occurred.

Errors

None.

mysql_row_seek()

MYSQL_ROW_OFFSET mysql_row_seek(MYSQL_RES *result, MYSQL_ROW_OFFSET offset)

Description

Sets the row cursor to an arbitrary row in a query result set. The offset value is a row offset, typically a value returned from mysql_row_tell() or from mysql_row_seek(). This value is not a row number; to seek to a row within a result set by number, use mysql_data_seek() instead.

This function requires that the result set structure contains the entire result of the query, so mysql_row_seek() may be used only in conjunction with mysql-store-result(), not with mysql_use_result().

Return Values

The previous value of the row cursor. This value may be passed to a subsequent call to mysql_row_seek().

Errors

None.

mysql_row_tell()

MYSQL_ROW_OFFSET mysql_row_tell(MYSQL_RES *result)

Description

Returns the current position of the row cursor for the last mysql_fetch_row(). This value can be used as an argument to mysql_row_seek().

Use mysql-row-tell() only after mysql_store_result(), not after mysql_use_result().

Return Values

The current offset of the row cursor.

Errors

None.

mysql_select_db()

int mysql_select_db(MYSQL *mysql, const char *db)

Description

Causes the database specified by db to become the default (current) database on the connection specified by MariaDB. In subsequent queries, this database is the default for table references that do not include an explicit database specifier.

mysql_select_db() fails unless the connected user can be authenticated as having permission to use the database.

Return Values

Zero for success. Nonzero if an error occurred.

Errors

mysql_set_character_set()

int mysql_set_character_set(MYSQL *mysql, const char *csname)

Description

This function is used to set the default character set for the current connection. The string csname specifies a valid character set name. The connection collation becomes the default collation of the character set. This function works like the SET NAMES statement, but also sets the value of mysql->charset, and thus affects the character set used by mysql_real_escape_string()

Return Values

Zero for success. Nonzero if an error occurred.

Example
MYSQL mysql;
mysql_init(&mysql);
if (!mysql_real_connect(&mysql,'host','user','passwd','database',0,NULL,0))
{
 fprintf(stderr, 'Failed to connect to database: Error: %s\n',
 mysql_error(&mysql));
}
if (!mysql_set_character_set(&mysql, 'utf8'))
{
 printf('New client character set: %s\n',
 mysql_character_set_name(&mysql));
}

mysql_set_local_infile_default()

void mysql_set_local_infile_default(MYSQL *mysql);

Description

Sets the LOAD LOCAL DATA INFILE handler callback functions to the defaults used internally by the C client library. The library calls this function automatically if mysql_set_local_infile_handler() has not been called or does not supply valid functions for each of its callbacks.

Return Values

None.

Errors

None.

mysql_set_local_infile_handler()

void mysql_set_local_infile_handler(MYSQL *mysql, int (*local_infile_init)(void **, const char *, void *), int (*local_infile_read)(void *, char *, unsigned int), void (*local_infile_end)(void *), int (*local_infile_error)(void *, char*, unsigned int), void *userdata);

Description

This function installs callbacks to be used during the execution of LOAD DATA LOCAL INFILE statements. It enables application programs to exert control over local (client-side) data file reading. The arguments are the connection handler, a set of pointers to callback functions, and a pointer to a data area that the callbacks can use to share information.

To use mysql_set_local_infile_handler(), you must write the following callback functions: 

int local_infile_init(void **ptr, const char *filename, void *userdata);

The initialization function. This is called once to do any setup necessary, open the data file, allocate data structures, and so forth. The first void** argument is a pointer to a pointer. You can set the pointer (that is, *ptr) to a value that will be passed to each of the other callbacks (as a void*). The callbacks can use this pointed-to value to maintain state information. The userdata argument is the same value that is passed to mysql_set_local_infile_handler().

Make the initialization function return zero for success, nonzero for an error. 

int local_infile_read(void *ptr, char *buf, unsigned int buf_len);

The data-reading function. This is called repeatedly to read the data file. buf points to the buffer where the read data is stored, and buf_len is the maximum number of bytes that the callback can read and store in the buffer. (It can read fewer bytes, but should not read more.)

The return value is the number of bytes read, or zero when no more data could be read (this indicates EOF). Return a value less than zero if an error occurs. 

void local_infile_end(void *ptr)

The termination function. This is called once after local_infile_read() has returned zero (EOF) or an error. Within this function, deallocate any memory allocated by local_infile_init() and perform any other cleanup necessary. It is invoked even if the initialization function returns an error. 

int local_infile_error(void *ptr,
 char *error_msg,
 unsigned int error_msg_len);

The error-handling function. This is called to get a textual error message to return to the user in case any of your other functions returns an error. error_msg points to the buffer into which the message is written, and error_msg_len is the length of the buffer. Write the message as a null-terminated string, at most error_msg_len-1 bytes long.

The return value is the error number.

Typically, the other callbacks store the error message in the data structure pointed to by ptr, so that local_infile_error() can copy the message from there into error_msg.

After calling mysql_set_local_infile_handler() in your C code and passing pointers to your callback functions, you can then issue a LOAD DATA LOCAL INFILE statement (for example, by using mysql_query()). The client library automatically invokes your callbacks. The file name specified in LOAD DATA LOCAL INFILE will be passed as the second parameter to the local_infile_init() callback.

Return Values

None.

Errors

None.

mysql_set_server_option()

int mysql_set_server_option(MYSQL *mysql, enum enum_mysql_set_option option)

Description

Enables or disables an option for the connection. option can have one of the following values.

Option Description
MYSQL_OPTION_MULTI_STATEMENTS_ON Enable multiple-statement support
MYSQL_OPTION_MULTI_STATEMENTS_OFF Disable multiple-statement support

If you enable multiple-statement support, you should retrieve results from calls to mysql_query() or mysql_real_query() by using a loop that calls mysql_next_result() to determine whether there are more results. For an example, see , "C API Support for Multiple Statement Execution".

Enabling multiple-statement support with MYSQL_OPTION_MULTI_STATEMENTS_ON does not have quite the same effect as enabling it by passing the CLIENT_MULTI_STATEMENTS flag to mysql_real_connect(): CLIENT_MULTI_STATEMENTS also enables CLIENT_MULTI_RESULTS. If you are using the CALL SQL statement in your programs, multiple-result support must be enabled; this means that MYSQL_OPTION_MULTI_STATEMENTS_ON by itself is insufficient to permit the use of CALL.

Return Values

Zero for success. Nonzero if an error occurred.

Errors

mysql_shutdown()

int mysql_shutdown(MYSQL *mysql, enum mysql_enum_shutdown_level shutdown_level)

Description

Asks the database server to shut down. The connected user must have the SHUTDOWN privilege. MariaDB 5.6 servers support only one type of shutdown; shutdown_level must be equal to SHUTDOWN_DEFAULT. Additional shutdown levels are planned to make it possible to choose the desired level. Dynamically linked executables which have been compiled with older versions of the libmysqlclient headers and call mysql_shutdown() need to be used with the old libmysqlclient dynamic library.

The shutdown process is described in , "The Shutdown Process".

Return Values

Zero for success. Nonzero if an error occurred.

Errors

mysql_sqlstate()

const char *mysql_sqlstate(MYSQL *mysql)

Description

Returns a null-terminated string containing the SQLSTATE error code for the most recently executed SQL statement. The error code consists of five characters. '00000' means "no error." The values are specified by ANSI SQL and ODBC. For a list of possible values, see Appendix C, Errors, Error Codes, and Common Problems.

SQLSTATE values returned by mysql_sqlstate() differ from MySQL-specific error numbers returned by mysql_errno(). For example, the mysql client program displays errors using the following format, where 1146 is the mysql_errno() value and '42S02' is the corresponding mysql_sqlstate() value: 

shell> SELECT * FROM no_such_table;
ERROR 1146 (42S02): Table 'test.no_such_table' doesn't exist

Not all MariaDB error numbers are mapped to SQLSTATE error codes. The value 'HY000' (general error) is used for unmapped error numbers.

If you call mysql-sqlstate() after mysql_real_connect() fails, mysql_sqlstate() might not return a useful value. For example, this happens if a host is blocked by the server and the connection is closed without any SQLSTATE value being sent to the client.

Return Values

A null-terminated character string containing the SQLSTATE error code.

See Also

See , "mysql-errno()", , "mysql_error()", and , "mysql_stmt_sqlstate()".

mysql_ssl_set()

my_bool mysql_ssl_set(MYSQL *mysql, const char *key, const char *cert, const char *ca, const char *capath, const char *cipher)

Description

mysql_ssl_set() is used for establishing secure connections using SSL. It must be called before mysql_real_connect().

mysql_ssl_set() does nothing unless SSL support is enabled in the client library.

MariaDB is the connection handler returned from mysql_init(). The other parameters are specified as follows:

Any unused SSL parameters may be given as NULL.

Return Values

This function always returns 0. If SSL setup is incorrect, mysql_real_connect() returns an error when you attempt to connect.

mysql_stat()

const char *mysql_stat(MYSQL *mysql)

Description

Returns a character string containing information similar to that provided by the mysqladmin status command. This includes uptime in seconds and the number of running threads, questions, reloads, and open tables.

Return Values

A character string describing the server status. NULL if an error occurred.

Errors

mysql_store_result()

MYSQL_RES *mysql_store_result(MYSQL *mysql)

Description

After invoking mysql-query() or mysql_real_query(), you must call mysql-store-result() or mysql_use_result() for every statement that successfully produces a result set (SELECT, SHOW, DESCRIBE, EXPLAIN, CHECK TABLE, and so forth). You must also call mysql_free_result() after you are done with the result set.

You don't have to call mysql-store-result() or mysql_use_result() for other statements, but it does not do any harm or cause any notable performance degradation if you call mysql_store_result() in all cases. You can detect whether the statement has a result set by checking whether mysql_store_result() returns a nonzero value (more about this later).

If you enable multiple-statement support, you should retrieve results from calls to mysql_query() or mysql_real_query() by using a loop that calls mysql_next_result() to determine whether there are more results. For an example, see , "C API Support for Multiple Statement Execution".

If you want to know whether a statement should return a result set, you can use mysql_field_count() to check for this. See , "mysql_field_count()".

mysql_store_result() reads the entire result of a query to the client, allocates a MYSQL_RES structure, and places the result into this structure.

mysql_store_result() returns a null pointer if the statement didn't return a result set (for example, if it was an INSERT statement).

mysql_store_result() also returns a null pointer if reading of the result set failed. You can check whether an error occurred by checking whether mysql-error() returns a nonempty string, mysql_errno() returns nonzero, or mysql_field_count() returns zero.

An empty result set is returned if there are no rows returned. (An empty result set differs from a null pointer as a return value.)

After you have called mysql_store_result() and gotten back a result that isn't a null pointer, you can call mysql_num_rows() to find out how many rows are in the result set.

You can call mysql-fetch-row() to fetch rows from the result set, or mysql_row_seek() and mysql_row_tell() to obtain or set the current row position within the result set.

See , "Why mysql_store_result() Sometimes Returns NULL After mysql_query() Returns Success".

Return Values

A MYSQL_RES result structure with the results. NULL (0) if an error occurred.

Errors

mysql-store-result() resets mysql_error() and mysql_errno() if it succeeds.

mysql_thread_id()

unsigned long mysql_thread_id(MYSQL *mysql)

Description

Returns the thread ID of the current connection. This value can be used as an argument to mysql_kill() to kill the thread.

If the connection is lost and you reconnect with mysql_ping(), the thread ID changes. This means you should not get the thread ID and store it for later. You should get it when you need it.

Return Values

The thread ID of the current connection.

Errors

None.

mysql_use_result()

MYSQL_RES *mysql_use_result(MYSQL *mysql)

Description

After invoking mysql-query() or mysql_real_query(), you must call mysql-store-result() or mysql_use_result() for every statement that successfully produces a result set (SELECT, SHOW, DESCRIBE, EXPLAIN, CHECK TABLE, and so forth). You must also call mysql_free_result() after you are done with the result set.

mysql_use_result() initiates a result set retrieval but does not actually read the result set into the client like mysql_store_result() does. Instead, each row must be retrieved individually by making calls to mysql_fetch_row(). This reads the result of a query directly from the server without storing it in a temporary table or local buffer, which is somewhat faster and uses much less memory than mysql_store_result(). The client allocates memory only for the current row and a communication buffer that may grow up to max_allowed_packet bytes.

On the other hand, you shouldn't use mysql_use_result() if you are doing a lot of processing for each row on the client side, or if the output is sent to a screen on which the user may type a ^S (stop scroll). This ties up the server and prevent other threads from updating any tables from which the data is being fetched.

When using mysql-use-result(), you must execute mysql_fetch_row() until a NULL value is returned, otherwise, the unfetched rows are returned as part of the result set for your next query. The C API gives the error Commands out of sync; you can't run this command now if you forget to do this!

You may not use mysql-data-seek(), mysql_row_seek(), mysql-row-tell(), mysql_num_rows(), or mysql_affected_rows() with a result returned from mysql-use-result(), nor may you issue other queries until mysql_use_result() has finished. (However, after you have fetched all the rows, mysql_num_rows() accurately returns the number of rows fetched.)

You must call mysql_free_result() once you are done with the result set.

When using the libmysqld embedded server, the memory benefits are essentially lost because memory usage incrementally increases with each row retrieved until mysql_free_result() is called.

Return Values

A MYSQL_RES result structure. NULL if an error occurred.

Errors

mysql-use-result() resets mysql_error() and mysql_errno() if it succeeds.

mysql_warning_count()

unsigned int mysql_warning_count(MYSQL *mysql)

Description

Returns the number of errors, warnings, and notes generated during execution of the previous SQL statement.

Return Values

The warning count.

Errors

None.

C API Prepared Statements

The MariaDB client/server protocol provides for the use of prepared statements. This capability uses the MYSQL_STMT statement handler data structure returned by the mysql_stmt_init() initialization function. Prepared execution is an efficient way to execute a statement more than once. The statement is first parsed to prepare it for execution. Then it is executed one or more times at a later time, using the statement handle returned by the initialization function.

Prepared execution is faster than direct execution for statements executed more than once, primarily because the query is parsed only once. In the case of direct execution, the query is parsed every time it is executed. Prepared execution also can provide a reduction of network traffic because for each execution of the prepared statement, it is necessary only to send the data for the parameters.

Prepared statements might not provide a performance increase in some situations. For best results, test your application both with prepared and nonprepared statements and choose whichever yields best performance.

Another advantage of prepared statements is that it uses a binary protocol that makes data transfer between client and server more efficient.

The following SQL statements can be used as prepared statements: 

CALL CREATE TABLE DELETE DO INSERT REPLACE SELECT SET UPDATE ANALYZE TABLE OPTIMIZE TABLE REPAIR TABLE CACHE INDEX CHANGE MASTER CHECKSUM {TABLE | TABLES}
{CREATE | RENAME | DROP} DATABASE
{CREATE | RENAME | DROP} USER FLUSH {TABLE | TABLES | TABLES WITH READ LOCK | HOSTS | PRIVILEGES
 | LOGS | STATUS | MASTER | SLAVE | DES_KEY_FILE | USER_RESOURCES}
GRANT REVOKE KILL LOAD INDEX INTO CACHE RESET {MASTER | SLAVE | QUERY CACHE}
SHOW BINLOG EVENTS SHOW CREATE {PROCEDURE | FUNCTION | EVENT | TABLE | VIEW}
SHOW {AUTHORS | CONTRIBUTORS | WARNINGS | ERRORS}
SHOW {MASTER | BINARY} LOGS SHOW {MASTER | SLAVE} STATUS SLAVE {START | STOP}
INSTALL PLUGIN UNINSTALL PLUGIN

Other statements are not yet supported in MariaDB 5.6.

Metadata changes to tables or views referred to by prepared statements are detected and cause automatic repreparation of the statement when it is next executed. For more information, see , "Automatic Prepared Statement Repreparation".

C API Prepared Statement Data Structures

C API Prepared Statement Type Codes
C API Prepared Statement Type Conversions

Prepared statements use several data structures:

The following discussion describes the prepared statement data types in detail. For examples that show how to use them, see , "mysql_stmt_execute()", and , "mysql_stmt_fetch()".

C API Prepared Statement Type Codes

The buffer_type member of MYSQL_BIND structures indicates the data type of the C language variable bound to a statement parameter or result set column. For input, buffer_type indicates the type of the variable containing the value to be sent to the server. For output, it indicates the type of the variable into which a value received from the server should be stored.

The following table shows the permissible values for the buffer_type member of MYSQL_BIND structures for input values sent to the server. The table shows the C variable types that you can use, the corresponding type codes, and the SQL data types for which the supplied value can be used without conversion. Choose the buffer_type value according to the data type of the C language variable that you are binding. For the integer types, you should also set the is_unsigned member to indicate whether the variable is signed or unsigned.

Input Variable C Type buffer_type Value SQL Type of Destination Value
signed char MYSQL_TYPE_TINY TINYINT
short int MYSQL_TYPE_SHORT SMALLINT
int MYSQL_TYPE_LONG INT
long long int MYSQL_TYPE_LONGLONG BIGINT
float MYSQL_TYPE_FLOAT FLOAT
double MYSQL_TYPE_DOUBLE DOUBLE
MYSQL_TIME MYSQL_TYPE_TIME TIME
MYSQL_TIME MYSQL_TYPE_DATE DATE
MYSQL_TIME MYSQL_TYPE_DATETIME DATETIME
MYSQL_TIME MYSQL_TYPE_TIMESTAMP TIMESTAMP
char[] MYSQL_TYPE_STRING TEXT, CHAR, VARCHAR
char[] MYSQL_TYPE_BLOB BLOB, BINARY, VARBINARY
MYSQL_TYPE_NULL NULL

Use MYSQL_TYPE_NULL as indicated in the description for the is_null member in , "C API Prepared Statement Data Structures".

For input string data, use MYSQL_TYPE_STRING or MYSQL_TYPE_BLOB depending on whether the value is a character (nonbinary) or binary string:

The following table shows the permissible values for the buffer_type member of MYSQL_BIND structures for output values received from the server. The table shows the SQL types of received values, the corresponding type codes that such values have in result set metadata, and the recommended C language data types to bind to the MYSQL_BIND structure to receive the SQL values without conversion. Choose the buffer_type value according to the data type of the C language variable that you are binding. For the integer types, you should also set the is_unsigned member to indicate whether the variable is signed or unsigned.

SQL Type of Received Value buffer_type Value Output Variable C Type
TINYINT MYSQL_TYPE_TINY signed char
SMALLINT MYSQL_TYPE_SHORT short int
MEDIUMINT MYSQL_TYPE_INT24 int
INT MYSQL_TYPE_LONG int
BIGINT MYSQL_TYPE_LONGLONG long long int
FLOAT MYSQL_TYPE_FLOAT float
DOUBLE MYSQL_TYPE_DOUBLE double
DECIMAL MYSQL_TYPE_NEWDECIMAL char[]
YEAR MYSQL_TYPE_SHORT short int
TIME MYSQL_TYPE_TIME MYSQL_TIME
DATE MYSQL_TYPE_DATE MYSQL_TIME
DATETIME MYSQL_TYPE_DATETIME MYSQL_TIME
TIMESTAMP MYSQL_TYPE_TIMESTAMP MYSQL_TIME
CHAR, BINARY MYSQL_TYPE_STRING char[]
VARCHAR, VARBINARY MYSQL_TYPE_VAR_STRING char[]
TINYBLOB, TINYTEXT MYSQL_TYPE_TINY_BLOB char[]
BLOB, TEXT MYSQL_TYPE_BLOB char[]
MEDIUMBLOB, MEDIUMTEXT MYSQL_TYPE_MEDIUM_BLOB char[]
LONGBLOB, LONGTEXT MYSQL_TYPE_LONG_BLOB char[]
BIT MYSQL_TYPE_BIT char[]

C API Prepared Statement Type Conversions

Prepared statements transmit data between the client and server using C language variables on the client side that correspond to SQL values on the server side. If there is a mismatch between the C variable type on the client side and the corresponding SQL value type on the server side, MariaDB performs implicit type conversions in both directions.

MySQL knows the type code for the SQL value on the server side. The buffer_type value in the MYSQL_BIND structure indicates the type code of the C variable that holds the value on the client side. The two codes together tell MariaDB what conversion must be performed, if any. Here are some examples:

Before binding variables to the MYSQL_BIND structures that are to be used for fetching column values, you can check the type codes for each column of the result set. This might be desirable if you want to determine which variable types would be best to use to avoid type conversions. To get the type codes, call mysql_stmt_result_metadata() after executing the prepared statement with mysql_stmt_execute(). The metadata provides access to the type codes for the result set as described in , "mysql_stmt_result_metadata()", and , "C API Data Structures".

To determine whether output string values in a result set returned from the server contain binary or nonbinary data, check whether the charsetnr value of the result set metadata is 63 (see , "C API Data Structures"). If so, the character set is binary, which indicates binary rather than nonbinary data. This enables you to distinguish BINARY from CHAR, VARBINARY from VARCHAR, and the BLOB types from the TEXT types.

If you cause the max_length member of the MYSQL_FIELD column metadata structures to be set (by calling mysql_stmt_attr_set()), be aware that the max_length values for the result set indicate the lengths of the longest string representation of the result values, not the lengths of the binary representation. That is, max_length does not necessarily correspond to the size of the buffers needed to fetch the values with the binary protocol used for prepared statements. Choose the size of the buffers according to the types of the variables into which you fetch the values. For example, a TINYINT column containing the value -128 might have a max_length value of 4. But the binary representation of any TINYINT value requires only 1 byte for storage, so you can supply a signed char variable in which to store the value and set is_unsigned to indicate that values are signed.

Metadata changes to tables or views referred to by prepared statements are detected and cause automatic repreparation of the statement when it is next executed. For more information, see , "Automatic Prepared Statement Repreparation".

C API Prepared Statement Function Overview

The functions available for prepared statement processing are summarized here and described in greater detail in a later section. See , "C API Prepared Statement Function Descriptions".

Function Description
mysql_stmt_affected_rows() Returns the number of rows changed, deleted, or inserted by prepared UPDATE, DELETE, or INSERT statement
mysql_stmt_attr_get() Gets value of an attribute for a prepared statement
mysql_stmt_attr_set() Sets an attribute for a prepared statement
mysql_stmt_bind_param() Associates application data buffers with the parameter markers in a prepared SQL statement
mysql_stmt_bind_result() Associates application data buffers with columns in a result set
mysql_stmt_close() Frees memory used by a prepared statement
mysql_stmt_data_seek() Seeks to an arbitrary row number in a statement result set
mysql_stmt_errno() Returns the error number for the last statement execution
mysql_stmt_error() Returns the error message for the last statement execution
mysql_stmt_execute() Executes a prepared statement
mysql_stmt_fetch() Fetches the next row of data from a result set and returns data for all bound columns
mysql_stmt_fetch_column() Fetch data for one column of the current row of a result set
mysql_stmt_field_count() Returns the number of result columns for the most recent statement
mysql_stmt_free_result() Free the resources allocated to a statement handle
mysql_stmt_init() Allocates memory for a MYSQL_STMT structure and initializes it
mysql_stmt_insert_id() Returns the ID generated for an AUTO_INCREMENT column by a prepared statement
mysql_stmt_next_result() Returns/initiates the next result in a multiple-result execution
mysql_stmt_num_rows() Returns the row count from a buffered statement result set
mysql_stmt_param_count() Returns the number of parameters in a prepared statement
mysql_stmt_param_metadata() (Return parameter metadata in the form of a result set) Currently, this function does nothing
mysql_stmt_prepare() Prepares an SQL statement string for execution
mysql_stmt_reset() Resets the statement buffers in the server
mysql_stmt_result_metadata() Returns prepared statement metadata in the form of a result set
mysql_stmt_row_seek() Seeks to a row offset in a statement result set, using value returned from mysql_stmt_row_tell()
mysql_stmt_row_tell() Returns the statement row cursor position
mysql_stmt_send_long_data() Sends long data in chunks to server
mysql_stmt_sqlstate() Returns the SQLSTATE error code for the last statement execution
mysql_stmt_store_result() Retrieves a complete result set to the client

Call mysql-stmt-init() to create a statement handle, then mysql_stmt_prepare() to prepare the statement string, mysql_stmt_bind_param() to supply the parameter data, and mysql_stmt_execute() to execute the statement. You can repeat the mysql_stmt_execute() by changing parameter values in the respective buffers supplied through mysql_stmt_bind_param().

You can send text or binary data in chunks to server using mysql_stmt_send_long_data(). See , "mysql_stmt_send_long_data()".

If the statement is a SELECT or any other statement that produces a result set, mysql_stmt_prepare() also returns the result set metadata information in the form of a MYSQL_RES result set through mysql_stmt_result_metadata().

You can supply the result buffers using mysql_stmt_bind_result(), so that the mysql_stmt_fetch() automatically returns data to these buffers. This is row-by-row fetching.

When statement execution has been completed, close the statement handle using mysql_stmt_close() so that all resources associated with it can be freed.

If you obtained a SELECT statement's result set metadata by calling mysql_stmt_result_metadata(), you should also free the metadata using mysql_free_result().

Execution Steps

To prepare and execute a statement, an application follows these steps:

  1. Create a prepared statement handle with mysql_stmt_init(). To prepare the statement on the server, call mysql_stmt_prepare() and pass it a string containing the SQL statement.
  2. If the statement will produce a result set, call mysql_stmt_result_metadata() to obtain the result set metadata. This metadata is itself in the form of result set, albeit a separate one from the one that contains the rows returned by the query. The metadata result set indicates how many columns are in the result and contains information about each column.
  3. Set the values of any parameters using mysql_stmt_bind_param(). All parameters must be set. Otherwise, statement execution returns an error or produces unexpected results.
  4. Call mysql_stmt_execute() to execute the statement.
  5. If the statement produces a result set, bind the data buffers to use for retrieving the row values by calling mysql_stmt_bind_result().
  6. Fetch the data into the buffers row by row by calling mysql_stmt_fetch() repeatedly until no more rows are found.
  7. Repeat steps 3 through 6 as necessary, by changing the parameter values and re-executing the statement.

When mysql_stmt_prepare() is called, the MariaDB client/server protocol performs these actions:

When mysql_stmt_execute() is called, the MariaDB client/server protocol performs these actions:

When mysql_stmt_fetch() is called, the MariaDB client/server protocol performs these actions:

If an error occurs, you can get the statement error number, error message, and SQLSTATE code using mysql_stmt_errno(), mysql_stmt_error(), and mysql_stmt_sqlstate(), respectively.

Prepared Statement Logging

For prepared statements that are executed with the mysql-stmt-prepare() and mysql_stmt_execute() C API functions, the server writes Prepare and Execute lines to the general query log so that you can tell when statements are prepared and executed.

Suppose that you prepare and execute a statement as follows:

  1. Call mysql_stmt_prepare() to prepare the statement string 'SELECT ?'.
  2. Call mysql_stmt_bind_param() to bind the value 3 to the parameter in the prepared statement.
  3. Call mysql_stmt_execute() to execute the prepared statement.

As a result of the preceding calls, the server writes the following lines to the general query log: 

Prepare [1] SELECT ?
Execute [1] SELECT 3

Each Prepare and Execute line in the log is tagged with a [N] statement identifier so that you can keep track of which prepared statement is being logged. N is a positive integer. If there are multiple prepared statements active simultaneously for the client, N may be greater than 1. Each Execute lines shows a prepared statement after substitution of data values for ? parameters.

C API Prepared Statement Function Descriptions

mysql_stmt_affected_rows()
mysql_stmt_attr_get()
mysql_stmt_attr_set()
mysql_stmt_bind_param()
mysql_stmt_bind_result()
mysql_stmt_close()
mysql_stmt_data_seek()
mysql_stmt_errno()
mysql_stmt_error()
mysql_stmt_execute()
mysql_stmt_fetch()
mysql_stmt_fetch_column()
mysql_stmt_field_count()
mysql_stmt_free_result()
mysql_stmt_init()
mysql_stmt_insert_id()
mysql_stmt_next_result()
mysql_stmt_num_rows()
mysql_stmt_param_count()
mysql_stmt_param_metadata()
mysql_stmt_prepare()
mysql_stmt_reset()
mysql_stmt_result_metadata()
mysql_stmt_row_seek()
mysql_stmt_row_tell()
mysql_stmt_send_long_data()
mysql_stmt_sqlstate()
mysql_stmt_store_result()

To prepare and execute queries, use the functions described in detail in the following sections.

All functions that operate with a MYSQL_STMT structure begin with the prefix mysql_stmt_.

To create a MYSQL_STMT handle, use the mysql_stmt_init() function.

mysql_stmt_affected_rows()

my_ulonglong mysql_stmt_affected_rows(MYSQL_STMT *stmt)

Description

mysql_stmt_affected_rows() may be called immediately after executing a statement with mysql_stmt_execute(). It is like mysql_affected_rows() but for prepared statements. For a description of what the affected-rows value returned by this function means, See , "mysql_affected_rows()".

Errors

None.

Example

See the Example in , "mysql_stmt_execute()".

mysql_stmt_attr_get()

my_bool mysql_stmt_attr_get(MYSQL_STMT *stmt, enum enum_stmt_attr_type option, void *arg)

Description

Can be used to get the current value for a statement attribute.

The option argument is the option that you want to get; the arg should point to a variable that should contain the option value. If the option is an integer, arg should point to the value of the integer.

See , "mysql_stmt_attr_set()", for a list of options and option types.

Return Values

Zero if successful. Nonzero if option is unknown.

Errors

None.

mysql_stmt_attr_set()

my_bool mysql_stmt_attr_set(MYSQL_STMT *stmt, enum enum_stmt_attr_type option, const void *arg)

Description

Can be used to affect behavior for a prepared statement. This function may be called multiple times to set several options.

The option argument is the option that you want to set. The arg argument is the value for the option. arg should point to a variable that is set to the desired attribute value. The variable type is as indicated in the following table.

The following table shows the possible option values.

Option Argument Type Function
STMT_ATTR_UPDATE_MAX_LENGTH my_bool * If set to 1, causes mysql_stmt_store_result() to update the metadata MYSQL_FIELD->max_length value.
STMT_ATTR_CURSOR_TYPE unsigned long * Type of cursor to open for statement when mysql_stmt_execute() is invoked. *arg can be CURSOR_TYPE_NO_CURSOR (the default) or CURSOR_TYPE_READ_ONLY.
STMT_ATTR_PREFETCH_ROWS unsigned long * Number of rows to fetch from server at a time when using a cursor. *arg can be in the range from 1 to the maximum value of unsigned long. The default is 1.

If you use the STMT_ATTR_CURSOR_TYPE option with CURSOR_TYPE_READ_ONLY, a cursor is opened for the statement when you invoke mysql_stmt_execute(). If there is already an open cursor from a previous mysql_stmt_execute() call, it closes the cursor before opening a new one. mysql_stmt_reset() also closes any open cursor before preparing the statement for re-execution. mysql_stmt_free_result() closes any open cursor.

If you open a cursor for a prepared statement, mysql_stmt_store_result() is unnecessary, because that function causes the result set to be buffered on the client side.

Return Values

Zero if successful. Nonzero if option is unknown.

Errors

None.

Example

The following example opens a cursor for a prepared statement and sets the number of rows to fetch at a time to 5: 

MYSQL_STMT *stmt;
int rc;
unsigned long type;
unsigned long prefetch_rows = 5;
stmt = mysql_stmt_init(mysql);
type = (unsigned long) CURSOR_TYPE_READ_ONLY;
rc = mysql_stmt_attr_set(stmt, STMT_ATTR_CURSOR_TYPE, (void*) &type);
/* ... check return value ... */
rc = mysql_stmt_attr_set(stmt, STMT_ATTR_PREFETCH_ROWS,
 (void*) &prefetch_rows);
/* ... check return value ... */

mysql_stmt_bind_param()

my_bool mysql_stmt_bind_param(MYSQL_STMT *stmt, MYSQL_BIND *bind)

Description

mysql_stmt_bind_param() is used to bind input data for the parameter markers in the SQL statement that was passed to mysql_stmt_prepare(). It uses MYSQL_BIND structures to supply the data. bind is the address of an array of MYSQL_BIND structures. The client library expects the array to contain one element for each "?" parameter marker that is present in the query.

Suppose that you prepare the following statement: 

INSERT INTO mytbl VALUES(?,?,?)

When you bind the parameters, the array of MYSQL_BIND structures must contain three elements, and can be declared like this: 

MYSQL_BIND bind[3];

, "C API Prepared Statement Data Structures", describes the members of each MYSQL_BIND element and how they should be set to provide input values.

Return Values

Zero if the bind operation was successful. Nonzero if an error occurred.

Errors
Example

See the Example in , "mysql_stmt_execute()".

mysql_stmt_bind_result()

my_bool mysql_stmt_bind_result(MYSQL_STMT *stmt, MYSQL_BIND *bind)

Description

mysql_stmt_bind_result() is used to associate (that is, bind) output columns in the result set to data buffers and length buffers. When mysql_stmt_fetch() is called to fetch data, the MariaDB client/server protocol places the data for the bound columns into the specified buffers.

All columns must be bound to buffers prior to calling mysql_stmt_fetch(). bind is the address of an array of MYSQL_BIND structures. The client library expects the array to contain one element for each column of the result set. If you do not bind columns to MYSQL_BIND structures, mysql_stmt_fetch() simply ignores the data fetch. The buffers should be large enough to hold the data values, because the protocol doesn't return data values in chunks.

A column can be bound or rebound at any time, even after a result set has been partially retrieved. The new binding takes effect the next time mysql_stmt_fetch() is called. Suppose that an application binds the columns in a result set and calls mysql_stmt_fetch(). The client/server protocol returns data in the bound buffers. Then suppose that the application binds the columns to a different set of buffers. The protocol places data into the newly bound buffers when the next call to mysql_stmt_fetch() occurs.

To bind a column, an application calls mysql_stmt_bind_result() and passes the type, address, and length of the output buffer into which the value should be stored. , "C API Prepared Statement Data Structures", describes the members of each MYSQL_BIND element and how they should be set to receive output values.

Return Values

Zero if the bind operation was successful. Nonzero if an error occurred.

Errors
Example

See the Example in , "mysql_stmt_fetch()".

mysql_stmt_close()

my_bool mysql_stmt_close(MYSQL_STMT *)

Description

Closes the prepared statement. mysql_stmt_close() also deallocates the statement handle pointed to by stmt.

If the current statement has pending or unread results, this function cancels them so that the next query can be executed.

Return Values

Zero if the statement was freed successfully. Nonzero if an error occurred.

Errors
Example

See the Example in , "mysql_stmt_execute()".

mysql_stmt_data_seek()

void mysql_stmt_data_seek(MYSQL_STMT *stmt, my_ulonglong offset)

Description

Seeks to an arbitrary row in a statement result set. The offset value is a row number and should be in the range from 0 to mysql_stmt_num_rows(stmt)-1.

This function requires that the statement result set structure contains the entire result of the last executed query, so mysql_stmt_data_seek() may be used only in conjunction with mysql_stmt_store_result().

Return Values

None.

Errors

None.

mysql_stmt_errno()

unsigned int mysql_stmt_errno(MYSQL_STMT *stmt)

Description

For the statement specified by stmt, mysql_stmt_errno() returns the error code for the most recently invoked statement API function that can succeed or fail. A return value of zero means that no error occurred. Client error message numbers are listed in the MariaDB errmsg.h header file. Server error message numbers are listed in mysqld_error.h. Errors also are listed at Appendix C, Errors, Error Codes, and Common Problems.

Return Values

An error code value. Zero if no error occurred.

Errors

None.

mysql_stmt_error()

const char *mysql_stmt_error(MYSQL_STMT *stmt)

Description

For the statement specified by stmt, mysql_stmt_error() returns a null-terminated string containing the error message for the most recently invoked statement API function that can succeed or fail. An empty string ('') is returned if no error occurred. This means the following two tests are equivalent: 

if(*mysql_stmt_errno(stmt))
{
 // an error occurred
}
if (mysql_stmt_error(stmt)[0])
{
 // an error occurred
}

The language of the client error messages may be changed by recompiling the MariaDB client library. Currently, you can choose error messages in several different languages.

Return Values

A character string that describes the error. An empty string if no error occurred.

Errors

None.

mysql_stmt_execute()

int mysql_stmt_execute(MYSQL_STMT *stmt)

Description

mysql_stmt_execute() executes the prepared query associated with the statement handle. The currently bound parameter marker values are sent to server during this call, and the server replaces the markers with this newly supplied data.

Statement processing following mysql_stmt_execute() depends on the type of statement:

For statements that generate a result set, you can request that mysql_stmt_execute() open a cursor for the statement by calling mysql_stmt_attr_set() before executing the statement. If you execute a statement multiple times, mysql_stmt_execute() closes any open cursor before opening a new one.

Metadata changes to tables or views referred to by prepared statements are detected and cause automatic repreparation of the statement when it is next executed. For more information, see , "Automatic Prepared Statement Repreparation".

Return Values

Zero if execution was successful. Nonzero if an error occurred.

Errors
Example

The following example demonstrates how to create and populate a table using mysql_stmt_init(), mysql_stmt_prepare(), mysql_stmt_param_count(), mysql-stmt-bind-param(), mysql_stmt_execute(), and mysql_stmt_affected_rows(). The MariaDB variable is assumed to be a valid connection handle. For an example that shows how to retrieve data, see , "mysql_stmt_fetch()". 

#define STRING_SIZE 50
#define DROP_SAMPLE_TABLE 'DROP TABLE IF EXISTS test_table'
#define CREATE_SAMPLE_TABLE 'CREATE TABLE test_table(col1 INT,\
 col2 VARCHAR(40),\
 col3 SMALLINT,\
 col4 TIMESTAMP)'
#define INSERT_SAMPLE 'INSERT INTO \
 test_table(col1,col2,col3) \
 VALUES(?,?,?)'
MYSQL_STMT *stmt;
MYSQL_BIND bind[3];
my_ulonglong affected_rows;
int param_count;
short small_data;
int int_data;
char str_data[STRING_SIZE];
unsigned long str_length;
my_bool is_null;
if (mysql_query(mysql, DROP_SAMPLE_TABLE))
{
 fprintf(stderr, ' DROP TABLE failed\n');
 fprintf(stderr, ' %s\n', mysql_error(mysql));
 exit(0);
}
if (mysql_query(mysql, CREATE_SAMPLE_TABLE))
{
 fprintf(stderr, ' CREATE TABLE failed\n');
 fprintf(stderr, ' %s\n', mysql_error(mysql));
 exit(0);
}
/* Prepare an INSERT query with 3 parameters */
/* (the TIMESTAMP column is not named; the server */
/* sets it to the current date and time) */
stmt = mysql_stmt_init(mysql);
if (!stmt)
{
 fprintf(stderr, ' mysql_stmt_init(), out of memory\n');
 exit(0);
}
if (mysql_stmt_prepare(stmt, INSERT_SAMPLE, strlen(INSERT_SAMPLE)))
{
 fprintf(stderr, ' mysql_stmt_prepare(), INSERT failed\n');
 fprintf(stderr, ' %s\n', mysql_stmt_error(stmt));
 exit(0);
}
fprintf(stdout, ' prepare, INSERT successful\n');
/* Get the parameter count from the statement */
param_count= mysql_stmt_param_count(stmt);
fprintf(stdout, ' total parameters in INSERT: %d\n', param_count);
if (param_count != 3) /* validate parameter count */
{
 fprintf(stderr, ' invalid parameter count returned by MySQL\n');
 exit(0);
}
/* Bind the data for all 3 parameters */
memset(bind, 0, sizeof(bind));
/* INTEGER PARAM */
/* This is a number type, so there is no need
 to specify buffer_length */
bind[0].buffer_type= MYSQL_TYPE_LONG;
bind[0].buffer= (char *)&int_data;
bind[0].is_null= 0;
bind[0].length= 0;
/* STRING PARAM */
bind[1].buffer_type= MYSQL_TYPE_STRING;
bind[1].buffer= (char *)str_data;
bind[1].buffer_length= STRING_SIZE;
bind[1].is_null= 0;
bind[1].length= &str_length;
/* SMALLINT PARAM */
bind[2].buffer_type= MYSQL_TYPE_SHORT;
bind[2].buffer= (char *)&small_data;
bind[2].is_null= &is_null;
bind[2].length= 0;
/* Bind the buffers */
if (mysql_stmt_bind_param(stmt, bind))
{
 fprintf(stderr, ' mysql_stmt_bind_param() failed\n');
 fprintf(stderr, ' %s\n', mysql_stmt_error(stmt));
 exit(0);
}
/* Specify the data values for the first row */
int_data= 10; /* integer */
strncpy(str_data, 'MySQL', STRING_SIZE); /* string */
str_length= strlen(str_data);
/* INSERT SMALLINT data as NULL */
is_null= 1;
/* Execute the INSERT statement - 1*/
if (mysql_stmt_execute(stmt))
{
 fprintf(stderr, ' mysql_stmt_execute(), 1 failed\n');
 fprintf(stderr, ' %s\n', mysql_stmt_error(stmt));
 exit(0);
}
/* Get the number of affected rows */
affected_rows= mysql_stmt_affected_rows(stmt);
fprintf(stdout, ' total affected rows(insert 1): %lu\n',
 (unsigned long) affected_rows);
if (affected_rows != 1) /* validate affected rows */
{
 fprintf(stderr, ' invalid affected rows by MySQL\n');
 exit(0);
}
/* Specify data values for second row,
 then re-execute the statement */
int_data= 1000;
strncpy(str_data, '
 The most popular Open Source database',
 STRING_SIZE);
str_length= strlen(str_data);
small_data= 1000; /* smallint */
is_null= 0; /* reset */
/* Execute the INSERT statement - 2*/
if (mysql_stmt_execute(stmt))
{
 fprintf(stderr, ' mysql_stmt_execute, 2 failed\n');
 fprintf(stderr, ' %s\n', mysql_stmt_error(stmt));
 exit(0);
}
/* Get the total rows affected */
affected_rows= mysql_stmt_affected_rows(stmt);
fprintf(stdout, ' total affected rows(insert 2): %lu\n',
 (unsigned long) affected_rows);
if (affected_rows != 1) /* validate affected rows */
{
 fprintf(stderr, ' invalid affected rows by MySQL\n');
 exit(0);
}
/* Close the statement */
if (mysql_stmt_close(stmt))
{
 fprintf(stderr, ' failed while closing the statement\n');
 fprintf(stderr, ' %s\n', mysql_stmt_error(stmt));
 exit(0);
}
Note

For complete examples on the use of prepared statement functions, refer to the file tests/mysql_client_test.c. This file can be obtained from a MariaDB source distribution or from the Bazaar source repository.

mysql_stmt_fetch()

int mysql_stmt_fetch(MYSQL_STMT *stmt)

Description

mysql_stmt_fetch() returns the next row in the result set. It can be called only while the result set exists; that is, after a call to mysql-stmt-execute() for a statement such as SELECT that produces a result set.

mysql-stmt-fetch() returns row data using the buffers bound by mysql_stmt_bind_result(). It returns the data in those buffers for all the columns in the current row set and the lengths are returned to the length pointer. All columns must be bound by the application before it calls mysql_stmt_fetch().

By default, result sets are fetched unbuffered a row at a time from the server. To buffer the entire result set on the client, call mysql_stmt_store_result() after binding the data buffers and before calling mysql_stmt_fetch().

If a fetched data value is a NULL value, the *is_null value of the corresponding MYSQL_BIND structure contains TRUE (1). Otherwise, the data and its length are returned in the *buffer and *length elements based on the buffer type specified by the application. Each numeric and temporal type has a fixed length, as listed in the following table. The length of the string types depends on the length of the actual data value, as indicated by data_length.

Type Length
MYSQL_TYPE_TINY 1
MYSQL_TYPE_SHORT 2
MYSQL_TYPE_LONG 4
MYSQL_TYPE_LONGLONG 8
MYSQL_TYPE_FLOAT 4
MYSQL_TYPE_DOUBLE 8
MYSQL_TYPE_TIME sizeof(MYSQL_TIME)
MYSQL_TYPE_DATE sizeof(MYSQL_TIME)
MYSQL_TYPE_DATETIME sizeof(MYSQL_TIME)
MYSQL_TYPE_STRING data length
MYSQL_TYPE_BLOB data_length

In some cases you might want to determine the length of a column value before fetching it with mysql_stmt_fetch(). For example, the value might be a long string or BLOB value for which you want to know how much space must be allocated. To accomplish this, you can use these strategies:

Return Values
Return Value Description
0 Successful, the data has been fetched to application data buffers.
1 Error occurred. Error code and message can be obtained by calling mysql_stmt_errno() and mysql_stmt_error().
MYSQL_NO_DATA No more rows/data exists
MYSQL_DATA_TRUNCATED Data truncation occurred

MYSQL_DATA_TRUNCATED is returned when truncation reporting is enabled. To determine which column values were truncated when this value is returned, check the error members of the MYSQL_BIND structures used for fetching values. Truncation reporting is enabled by default, but can be controlled by calling mysql_options() with the MYSQL_REPORT_DATA_TRUNCATION option.

Errors
Example

The following example demonstrates how to fetch data from a table using mysql_stmt_result_metadata(), mysql_stmt_bind_result(), and mysql_stmt_fetch(). (This example expects to retrieve the two rows inserted by the example shown in , "mysql_stmt_execute()".) The MariaDB variable is assumed to be a valid connection handle. 

#define STRING_SIZE 50
#define SELECT_SAMPLE 'SELECT col1, col2, col3, col4 \
 FROM test_table'
MYSQL_STMT *stmt;
MYSQL_BIND bind[4];
MYSQL_RES *prepare_meta_result;
MYSQL_TIME ts;
unsigned long length[4];
int param_count, column_count, row_count;
short small_data;
int int_data;
char str_data[STRING_SIZE];
my_bool is_null[4];
my_bool error[4];
/* Prepare a SELECT query to fetch data from test_table */
stmt = mysql_stmt_init(mysql);
if (!stmt)
{
 fprintf(stderr, ' mysql_stmt_init(), out of memory\n');
 exit(0);
}
if (mysql_stmt_prepare(stmt, SELECT_SAMPLE, strlen(SELECT_SAMPLE)))
{
 fprintf(stderr, ' mysql_stmt_prepare(), SELECT failed\n');
 fprintf(stderr, ' %s\n', mysql_stmt_error(stmt));
 exit(0);
}
fprintf(stdout, ' prepare, SELECT successful\n');
/* Get the parameter count from the statement */
param_count= mysql_stmt_param_count(stmt);
fprintf(stdout, ' total parameters in SELECT: %d\n', param_count);
if (param_count != 0) /* validate parameter count */
{
 fprintf(stderr, ' invalid parameter count returned by MySQL\n');
 exit(0);
}
/* Fetch result set meta information */
prepare_meta_result = mysql_stmt_result_metadata(stmt);
if (!prepare_meta_result)
{
 fprintf(stderr,
 ' mysql_stmt_result_metadata(), \
 returned no meta information\n');
 fprintf(stderr, ' %s\n', mysql_stmt_error(stmt));
 exit(0);
}
/* Get total columns in the query */
column_count= mysql_num_fields(prepare_meta_result);
fprintf(stdout,
 ' total columns in SELECT statement: %d\n',
 column_count);
if (column_count != 4) /* validate column count */
{
 fprintf(stderr, ' invalid column count returned by MySQL\n');
 exit(0);
}
/* Execute the SELECT query */
if (mysql_stmt_execute(stmt))
{
 fprintf(stderr, ' mysql_stmt_execute(), failed\n');
 fprintf(stderr, ' %s\n', mysql_stmt_error(stmt));
 exit(0);
}
/* Bind the result buffers for all 4 columns before fetching them */
memset(bind, 0, sizeof(bind));
/* INTEGER COLUMN */
bind[0].buffer_type= MYSQL_TYPE_LONG;
bind[0].buffer= (char *)&int_data;
bind[0].is_null= &is_null[0];
bind[0].length= &length[0];
bind[0].error= &error[0];
/* STRING COLUMN */
bind[1].buffer_type= MYSQL_TYPE_STRING;
bind[1].buffer= (char *)str_data;
bind[1].buffer_length= STRING_SIZE;
bind[1].is_null= &is_null[1];
bind[1].length= &length[1];
bind[1].error= &error[1];
/* SMALLINT COLUMN */
bind[2].buffer_type= MYSQL_TYPE_SHORT;
bind[2].buffer= (char *)&small_data;
bind[2].is_null= &is_null[2];
bind[2].length= &length[2];
bind[2].error= &error[2];
/* TIMESTAMP COLUMN */
bind[3].buffer_type= MYSQL_TYPE_TIMESTAMP;
bind[3].buffer= (char *)&ts;
bind[3].is_null= &is_null[3];
bind[3].length= &length[3];
bind[3].error= &error[3];
/* Bind the result buffers */
if (mysql_stmt_bind_result(stmt, bind))
{
 fprintf(stderr, ' mysql_stmt_bind_result() failed\n');
 fprintf(stderr, ' %s\n', mysql_stmt_error(stmt));
 exit(0);
}
/* Now buffer all results to client (optional step) */
if (mysql_stmt_store_result(stmt))
{
 fprintf(stderr, ' mysql_stmt_store_result() failed\n');
 fprintf(stderr, ' %s\n', mysql_stmt_error(stmt));
 exit(0);
}
/* Fetch all rows */
row_count= 0;
fprintf(stdout, 'Fetching results ...\n');
while (!mysql_stmt_fetch(stmt))
{
 row_count++;
 fprintf(stdout, ' row %d\n', row_count);
 /* column 1 */
 fprintf(stdout, ' column1 (integer) : ');
 if (is_null[0])
 fprintf(stdout, ' NULL\n');
 else
 fprintf(stdout, ' %d(%ld)\n', int_data, length[0]);
 /* column 2 */
 fprintf(stdout, ' column2 (string) : ');
 if (is_null[1])
 fprintf(stdout, ' NULL\n');
 else
 fprintf(stdout, ' %s(%ld)\n', str_data, length[1]);
 /* column 3 */
 fprintf(stdout, ' column3 (smallint) : ');
 if (is_null[2])
 fprintf(stdout, ' NULL\n');
 else
 fprintf(stdout, ' %d(%ld)\n', small_data, length[2]);
 /* column 4 */
 fprintf(stdout, ' column4 (timestamp): ');
 if (is_null[3])
 fprintf(stdout, ' NULL\n');
 else
 fprintf(stdout, ' %04d-%02d-%02d %02d:%02d:%02d (%ld)\n',
 ts.year, ts.month, ts.day,
 ts.hour, ts.minute, ts.second,
 length[3]);
 fprintf(stdout, '\n');
}
/* Validate rows fetched */
fprintf(stdout, ' total rows fetched: %d\n', row_count);
if (row_count != 2)
{
 fprintf(stderr, ' MariaDB failed to return all rows\n');
 exit(0);
}
/* Free the prepared result metadata */
mysql_free_result(prepare_meta_result);
/* Close the statement */
if (mysql_stmt_close(stmt))
{
 fprintf(stderr, ' failed while closing the statement\n');
 fprintf(stderr, ' %s\n', mysql_stmt_error(stmt));
 exit(0);
}

mysql_stmt_fetch_column()

int mysql_stmt_fetch_column(MYSQL_STMT *stmt, MYSQL_BIND *bind, unsigned int column, unsigned long offset)

Description

Fetch one column from the current result set row. bind provides the buffer where data should be placed. It should be set up the same way as for mysql_stmt_bind_result(). column indicates which column to fetch. The first column is numbered 0. offset is the offset within the data value at which to begin retrieving data. This can be used for fetching the data value in pieces. The beginning of the value is offset 0.

Return Values

Zero if the value was fetched successfully. Nonzero if an error occurred.

Errors

mysql_stmt_field_count()

unsigned int mysql_stmt_field_count(MYSQL_STMT *stmt)

Description

Returns the number of columns for the most recent statement for the statement handler. This value is zero for statements such as INSERT or DELETE that do not produce result sets.

mysql_stmt_field_count() can be called after you have prepared a statement by invoking mysql_stmt_prepare().

Return Values

An unsigned integer representing the number of columns in a result set.

Errors

None.

mysql_stmt_free_result()

my_bool mysql_stmt_free_result(MYSQL_STMT *stmt)

Description

Releases memory associated with the result set produced by execution of the prepared statement. If there is a cursor open for the statement, mysql_stmt_free_result() closes it.

Return Values

Zero if the result set was freed successfully. Nonzero if an error occurred.

Errors

mysql_stmt_init()

MYSQL_STMT *mysql_stmt_init(MYSQL *mysql)

Description

Create a MYSQL_STMT handle. The handle should be freed with mysql_stmt_close(MYSQL_STMT *).

See also , "C API Prepared Statement Data Structures", for more information.

Return Values

A pointer to a MYSQL_STMT structure in case of success. NULL if out of memory.

Errors

mysql_stmt_insert_id()

my_ulonglong mysql_stmt_insert_id(MYSQL_STMT *stmt)

Description

Returns the value generated for an AUTO_INCREMENT column by the prepared INSERT or UPDATE statement. Use this function after you have executed a prepared INSERT statement on a table which contains an AUTO_INCREMENT field.

See , "mysql_insert_id()", for more information.

Return Values

Value for AUTO_INCREMENT column which was automatically generated or explicitly set during execution of prepared statement, or value generated by LAST_INSERT_ID(expr) function. Return value is undefined if statement does not set AUTO_INCREMENT value.

Errors

None.

mysql_stmt_next_result()

int mysql_stmt_next_result(MYSQL_STMT *mysql)

Description

This function is used when you use prepared CALL statements to execute stored procedures, which can return multiple result sets. Use a loop that calls mysql_stmt_next_result() to determine whether there are more results. If a procedure has OUT or INOUT parameters, their values will be returned as a single-row result set following any other result sets. The values will appear in the order in which they are declared in the procedure parameter list.

mysql_stmt_next_result() returns a status to indicate whether more results exist. If mysql_stmt_next_result() returns an error, there are no more results.

Before each call to mysql-stmt-next-result(), you must call mysql_stmt_free_result() for the current result if it produced a result set (rather than just a result status).

After calling mysql_stmt_next_result() the state of the connection is as if you had called mysql_stmt_execute(). This means that you can call mysql_stmt_bind_result(), mysql_stmt_affected_rows(), and so forth.

It is also possible to test whether there are more results by calling mysql_more_results(). However, this function does not change the connection state, so if it returns true, you must still call mysql_stmt_next_result() to advance to the next result.

For an example that shows how to use mysql_stmt_next_result(), see , "C API Support for Prepared CALL Statements".

Return Values
Return Value Description
0 Successful and there are more results
-1 Successful and there are no more results
>0 An error occurred
Errors

mysql_stmt_num_rows()

my_ulonglong mysql_stmt_num_rows(MYSQL_STMT *stmt)

Description

Returns the number of rows in the result set.

The use of mysql-stmt-num-rows() depends on whether you used mysql_stmt_store_result() to buffer the entire result set in the statement handle. If you use mysql_stmt_store_result(), mysql_stmt_num_rows() may be called immediately. Otherwise, the row count is unavailable unless you count the rows as you fetch them.

mysql-stmt-num-rows() is intended for use with statements that return a result set, such as SELECT. For statements such as INSERT, UPDATE, or DELETE, the number of affected rows can be obtained with mysql_stmt_affected_rows().

Return Values

The number of rows in the result set.

Errors

None.

mysql_stmt_param_count()

unsigned long mysql_stmt_param_count(MYSQL_STMT *stmt)

Description

Returns the number of parameter markers present in the prepared statement.

Return Values

An unsigned long integer representing the number of parameters in a statement.

Errors

None.

Example

See the Example in , "mysql_stmt_execute()".

mysql_stmt_param_metadata()

MYSQL_RES *mysql_stmt_param_metadata(MYSQL_STMT *stmt)

This function currently does nothing.

Description
Return Values
Errors

mysql_stmt_prepare()

int mysql_stmt_prepare(MYSQL_STMT *stmt, const char *stmt_str, unsigned long length)

Description

Given the statement handle returned by mysql_stmt_init(), prepares the SQL statement pointed to by the string stmt_str and returns a status value. The string length should be given by the length argument. The string must consist of a single SQL statement. You should not add a terminating semicolon (";") or \g to the statement.

The application can include one or more parameter markers in the SQL statement by embedding question mark ("?") characters into the SQL string at the appropriate positions.

The markers are legal only in certain places in SQL statements. For example, they are permitted in the VALUES() list of an INSERT statement (to specify column values for a row), or in a comparison with a column in a WHERE clause to specify a comparison value. However, they are not permitted for identifiers (such as table or column names), or to specify both operands of a binary operator such as the = equal sign. The latter restriction is necessary because it would be impossible to determine the parameter type. In general, parameters are legal only in Data Manipulation Language (DML) statements, and not in Data Definition Language (DDL) statements.

The parameter markers must be bound to application variables using mysql_stmt_bind_param() before executing the statement.

Metadata changes to tables or views referred to by prepared statements are detected and cause automatic repreparation of the statement when it is next executed. For more information, see , "Automatic Prepared Statement Repreparation".

Return Values

Zero if the statement was prepared successfully. Nonzero if an error occurred.

Errors

If the prepare operation was unsuccessful (that is, mysql_stmt_prepare() returns nonzero), the error message can be obtained by calling mysql_stmt_error().

Example

See the Example in , "mysql_stmt_execute()".

mysql_stmt_reset()

my_bool mysql_stmt_reset(MYSQL_STMT *stmt)

Description

Resets a prepared statement on client and server to state after prepare. It resets the statement on the server, data sent using mysql_stmt_send_long_data(), unbuffered result sets and current errors. It does not clear bindings or stored result sets. Stored result sets will be cleared when executing the prepared statement (or closing it).

To re-prepare the statement with another query, use mysql_stmt_prepare().

Return Values

Zero if the statement was reset successfully. Nonzero if an error occurred.

Errors

mysql_stmt_result_metadata()

MYSQL_RES *mysql_stmt_result_metadata(MYSQL_STMT *stmt)

Description

If a statement passed to mysql_stmt_prepare() is one that produces a result set, mysql_stmt_result_metadata() returns the result set metadata in the form of a pointer to a MYSQL_RES structure that can be used to process the meta information such as number of fields and individual field information. This result set pointer can be passed as an argument to any of the field-based API functions that process result set metadata, such as:

The result set structure should be freed when you are done with it, which you can do by passing it to mysql_free_result(). This is similar to the way you free a result set obtained from a call to mysql_store_result().

The result set returned by mysql_stmt_result_metadata() contains only metadata. It does not contain any row results. The rows are obtained by using the statement handle with mysql_stmt_fetch().

Return Values

A MYSQL_RES result structure. NULL if no meta information exists for the prepared query.

Errors
Example

See the Example in , "mysql_stmt_fetch()".

mysql_stmt_row_seek()

MYSQL_ROW_OFFSET mysql_stmt_row_seek(MYSQL_STMT *stmt, MYSQL_ROW_OFFSET offset)

Description

Sets the row cursor to an arbitrary row in a statement result set. The offset value is a row offset that should be a value returned from mysql_stmt_row_tell() or from mysql_stmt_row_seek(). This value is not a row number; if you want to seek to a row within a result set by number, use mysql_stmt_data_seek() instead.

This function requires that the result set structure contains the entire result of the query, so mysql_stmt_row_seek() may be used only in conjunction with mysql_stmt_store_result().

Return Values

The previous value of the row cursor. This value may be passed to a subsequent call to mysql_stmt_row_seek().

Errors

None.

mysql_stmt_row_tell()

MYSQL_ROW_OFFSET mysql_stmt_row_tell(MYSQL_STMT *stmt)

Description

Returns the current position of the row cursor for the last mysql_stmt_fetch(). This value can be used as an argument to mysql_stmt_row_seek().

You should use mysql-stmt-row-tell() only after mysql_stmt_store_result().

Return Values

The current offset of the row cursor.

Errors

None.

mysql_stmt_send_long_data()

my_bool mysql_stmt_send_long_data(MYSQL_STMT *stmt, unsigned int parameter_number, const char *data, unsigned long length)

Description

Enables an application to send parameter data to the server in pieces (or "chunks"). Call this function after mysql_stmt_bind_param() and before mysql_stmt_execute(). It can be called multiple times to send the parts of a character or binary data value for a column, which must be one of the TEXT or BLOB data types.

parameter_number indicates which parameter to associate the data with. Parameters are numbered beginning with 0. data is a pointer to a buffer containing data to be sent, and length indicates the number of bytes in the buffer.Note

The next mysql_stmt_execute() call ignores the bind buffer for all parameters that have been used with mysql_stmt_send_long_data() since last mysql_stmt_execute() or mysql_stmt_reset().

If you want to reset/forget the sent data, you can do it with mysql_stmt_reset(). See , "mysql_stmt_reset()".

As of MariaDB 5.6.3, the max_allowed_packet system variable controls the maximum size of parameter values that can be sent with mysql_stmt_send_long_data().

Return Values

Zero if the data is sent successfully to server. Nonzero if an error occurred.

Errors
Example

The following example demonstrates how to send the data for a TEXT column in chunks. It inserts the data value 'MySQL - The most popular Open Source database' into the text_column column. The MariaDB variable is assumed to be a valid connection handle. 

#define INSERT_QUERY 'INSERT INTO \
 test_long_data(text_column) VALUES(?)'
MYSQL_BIND bind[1];
long length;
stmt = mysql_stmt_init(mysql);
if (!stmt)
{
 fprintf(stderr, ' mysql_stmt_init(), out of memory\n');
 exit(0);
}
if (mysql_stmt_prepare(stmt, INSERT_QUERY, strlen(INSERT_QUERY)))
{
 fprintf(stderr, '\n mysql_stmt_prepare(), INSERT failed');
 fprintf(stderr, '\n %s', mysql_stmt_error(stmt));
 exit(0);
}
 memset(bind, 0, sizeof(bind));
 bind[0].buffer_type= MYSQL_TYPE_STRING;
 bind[0].length= &length;
 bind[0].is_null= 0;
/* Bind the buffers */
if (mysql_stmt_bind_param(stmt, bind))
{
 fprintf(stderr, '\n param bind failed');
 fprintf(stderr, '\n %s', mysql_stmt_error(stmt));
 exit(0);
}
 /* Supply data in chunks to server */
 if (mysql_stmt_send_long_data(stmt,0,'MySQL',5))
{
 fprintf(stderr, '\n send_long_data failed');
 fprintf(stderr, '\n %s', mysql_stmt_error(stmt));
 exit(0);
}
 /* Supply the next piece of data */
 if (mysql_stmt_send_long_data(stmt,0,
 ' - The most popular Open Source database',40))
{
 fprintf(stderr, '\n send_long_data failed');
 fprintf(stderr, '\n %s', mysql_stmt_error(stmt));
 exit(0);
}
 /* Now, execute the query */
 if (mysql_stmt_execute(stmt))
{
 fprintf(stderr, '\n mysql_stmt_execute failed');
 fprintf(stderr, '\n %s', mysql_stmt_error(stmt));
 exit(0);
}

mysql_stmt_sqlstate()

const char *mysql_stmt_sqlstate(MYSQL_STMT *stmt)

Description

For the statement specified by stmt, mysql_stmt_sqlstate() returns a null-terminated string containing the SQLSTATE error code for the most recently invoked prepared statement API function that can succeed or fail. The error code consists of five characters. '00000' means "no error." The values are specified by ANSI SQL and ODBC. For a list of possible values, see Appendix C, Errors, Error Codes, and Common Problems.

Note that not all MariaDB errors are yet mapped to SQLSTATE codes. The value 'HY000' (general error) is used for unmapped errors.

Return Values

A null-terminated character string containing the SQLSTATE error code.

mysql_stmt_store_result()

int mysql_stmt_store_result(MYSQL_STMT *stmt)

Description

Result sets are produced by calling mysql_stmt_execute() to executed prepared statements for SQL statements such as SELECT, SHOW, DESCRIBE, and EXPLAIN. By default, result sets for successfully executed prepared statements are not buffered on the client and mysql_stmt_fetch() fetches them one at a time from the server. To cause the complete result set to be buffered on the client, call mysql_stmt_store_result() after binding data buffers with mysql_stmt_bind_result() and before calling mysql_stmt_fetch() to fetch rows. (For an example, see , "mysql_stmt_fetch()".)

mysql_stmt_store_result() is optional for result set processing, unless you will call mysql_stmt_data_seek(), mysql_stmt_row_seek(), or mysql_stmt_row_tell(). Those functions require a seekable result set.

It is unnecessary to call mysql_stmt_store_result() after executing an SQL statement that does not produce a result set, but if you do, it does not harm or cause any notable performance problem. You can detect whether the statement produced a result set by checking if mysql_stmt_result_metadata() returns NULL. For more information, refer to , "mysql_stmt_result_metadata()".Note

MySQL doesn't by default calculate MYSQL_FIELD->max_length for all columns in mysql_stmt_store_result() because calculating this would slow down mysql_stmt_store_result() considerably and most applications don't need max_length. If you want max_length to be updated, you can call mysql_stmt_attr_set(MYSQL_STMT, STMT_ATTR_UPDATE_MAX_LENGTH, &flag) to enable this. See , "mysql_stmt_attr_set()".

Return Values

Zero if the results are buffered successfully. Nonzero if an error occurred.

Errors

C API Threaded Function Descriptions

my_init()
mysql_thread_end()
mysql_thread_init()
mysql_thread_safe()

To create a threaded client, use the functions described in the following sections. See also , "How to Write a Threaded Client".

my_init()

void my_init(void)

Description

my-init() initializes some global variables that MariaDB needs. It also calls mysql_thread_init() for this thread.

It is necessary for my_init() to be called early in the initialization phase of a program's use of the MariaDB library. However, my_init() is automatically called by mysql_init(), mysql-library-init(), mysql_server_init(), and mysql_connect(). If you ensure that your program invokes one of those functions before any other MariaDB calls, there is no need to invoke my_init() explicitly.

To access the prototype for my_init(), your program should include these header files: 

#include <my_global.h>
#include <my_sys.h>
Return Values

None.

mysql_thread_end()

void mysql_thread_end(void)

Description

This function needs to be called before calling pthread_exit() to free memory allocated by mysql_thread_init().

mysql_thread_end() is not invoked automatically by the client library. It must be called explicitly to avoid a memory leak.

Return Values

None.

mysql_thread_init()

my_bool mysql_thread_init(void)

Description

This function must be called early within each created thread to initialize thread-specific variables. However, you may not necessarily need to invoke it explicitly: mysql_thread_init() is automatically called by my_init(), which itself is automatically called by mysql-init(), mysql_library_init(), mysql-server-init(), and mysql_connect(). If you invoke any of those functions, mysql_thread_init() will be called for you.

Return Values

Zero if successful. Nonzero if an error occurred.

mysql_thread_safe()

unsigned int mysql_thread_safe(void)

Description

This function indicates whether the client library is compiled as thread-safe.

Return Values

1 if the client library is thread-safe, 0 otherwise.

C API Embedded Server Function Descriptions

mysql_server_init()
mysql_server_end()

MySQL applications can be written to use an embedded server. See , "libmysqld, the Embedded MariaDB Server Library". To write such an application, you must link it against the libmysqld library by using the -lmysqld flag rather than linking it against the libmysqlclient client library by using the -lmysqlclient flag. However, the calls to initialize and finalize the library are the same whether you write a client application or one that uses the embedded server: Call mysql_library_init() to initialize the library and mysql_library_end() when you are done with it. See , "C API Function Overview".

mysql_server_init()

int mysql_server_init(int argc, char **argv, char **groups)

Description

This function initializes the MariaDB library, which must be done before you call any other MariaDB function. However, mysql_server_init() is deprecated and you should call mysql_library_init() instead. See , "mysql_library_init()".

Return Values

Zero if successful. Nonzero if an error occurred.

mysql_server_end()

void mysql_server_end(void)

Description

This function finalizes the MariaDB library, which should be done when you are done using the library. However, mysql_server_end() is deprecated and mysql-library-end() should be used instead. See , "mysql_library_end()".

Return Values

None.

C API Client Plugin Functions

mysql_client_find_plugin()
mysql_client_register_plugin()
mysql_load_plugin()
mysql_load_plugin_v()
mysql_plugin_options()

This section describes functions used for the client-side plugin API. They enable management of client plugins. For a description of the st_mysql_client_plugin structure used by these functions, see , "Client Plugin Descriptors".

It is unlikely that a client program needs to call the functions in this section. For example, a client that supports the use of authentication plugins normally causes a plugin to be loaded by calling mysql_options() to set the MYSQL_DEFAULT_AUTH and MYSQL_PLUGIN_DIR options: 

char *plugin_dir = 'path_to_plugin_dir';
char *default_auth = 'plugin_name';
/* ... process command-line options ... */
mysql_options(&mysql, MYSQL_PLUGIN_DIR, plugin_dir);
mysql_options(&mysql, MYSQL_DEFAULT_AUTH, default_auth);

Typically, the program will also accept --plugin-dir and --default-auth options that enable users to override the default values.

mysql_client_find_plugin()

struct st_mysql_client_plugin *mysql_client_find_plugin(MYSQL *mysql, const char *name, int type)

Description

Returns a pointer to a loaded plugin, loading the plugin first if necessary. An error occurs if the type is invalid or the plugin cannot be found or loaded.

Specify the parameters as follows:

Return Values

A pointer to the plugin for success. NULL if an error occurred.

Errors

To check for errors, call the mysql-error() or mysql_errno() function. See , "mysql-error()", and , "mysql_errno()".

Example
MYSQL mysql;
struct st_mysql_client_plugin *p;
if ((p = mysql_client_find_plugin(&mysql, 'myplugin',
 MYSQL_AUTHENTICATION_PLUGIN, 0)))
{
 printf('Plugin version: %d.%d.%d\n', p->version[0], p->version[1], p->version[2]);
}

mysql_client_register_plugin()

struct st_mysql_client_plugin *mysql_client_register_plugin(MYSQL *mysql, struct st_mysql_client_plugin *plugin)

Description

Adds a plugin structure to the list of loaded plugins. An error occurs if the plugin is already loaded.

Specify the parameters as follows:

Return Values

A pointer to the plugin for success. NULL if an error occurred.

Errors

To check for errors, call the mysql-error() or mysql_errno() function. See , "mysql-error()", and , "mysql_errno()".

mysql_load_plugin()

struct st_mysql_client_plugin *mysql_load_plugin(MYSQL *mysql, const char *name, int type, int argc, ...)

Description

Loads a MariaDB client plugin, specified by name and type. An error occurs if the type is invalid or the plugin cannot be loaded.

It is not possible to load multiple plugins of the same type. An error occurs if you try to load a plugin of a type already loaded.

Specify the parameters as follows:

Another way to cause plugins to be loaded is to set the LIBMYSQL_PLUGINS environment variable to a semicolon-separated list of plugin names. For example: 

shell> export LIBMYSQL_PLUGINS='myplugin1;myplugin2'

Plugins named by LIBMYSQL_PLUGINS are loaded when the client program calls mysql_library_init(). No error is reported if problems occur loading these plugins.

Return Values

A pointer to the plugin if it was loaded successfully. NULL if an error occurred.

Errors

To check for errors, call the mysql-error() or mysql_errno() function. See , "mysql-error()", and , "mysql_errno()".

Example
MYSQL mysql;
if(!mysql_load_plugin(&mysql, 'myplugin',
 MYSQL_AUTHENTICATION_PLUGIN, 0))
{
 fprintf(stderr, 'Error: %s\n', mysql_error(&mysql));
 exit(-1);
}
See Also

See also , "mysql-load-plugin()", , "mysql_error()", , "mysql_errno()".

mysql_load_plugin_v()

struct st_mysql_client_plugin *mysql_load_plugin_v(MYSQL *mysql, const char *name, int type, int argc, va_list args)

Description

This function is equivalent to mysql_load_plugin(), but it accepts a va_list instead of a variable list of parameters.

See Also

See also , "mysql_load_plugin()".

mysql_plugin_options()

int mysql_plugin_options(struct st_mysql_client_plugin *plugin, const char *option, const void *value)

Description

Passes an option type and value to a plugin. This function can be called multiple times to set several options. If the plugin does not have an option handler, an error occurs.

Specify the parameters as follows:

Return Values

Zero for success, 1 if an error occurred. If the plugin has an option handler, that handler should also return zero for success and 1 if an error occurred.

Common Questions and Problems When Using the C API

Why mysql_store_result() Sometimes Returns NULL After mysql_query() Returns Success
What Results You Can Get from a Query
How to Get the Unique ID for the Last Inserted Row

Why mysql_store_result() Sometimes Returns NULL After mysql_query() Returns Success

It is possible for mysql_store_result() to return NULL following a successful call to mysql_query(). When this happens, it means one of the following conditions occurred:

You can always check whether the statement should have produced a nonempty result by calling mysql_field_count(). If mysql_field_count() returns zero, the result is empty and the last query was a statement that does not return values (for example, an INSERT or a DELETE). If mysql_field_count() returns a nonzero value, the statement should have produced a nonempty result. See the description of the mysql_field_count() function for an example.

You can test for an error by calling mysql-error() or mysql_errno().

What Results You Can Get from a Query

In addition to the result set returned by a query, you can also get the following information:

How to Get the Unique ID for the Last Inserted Row

If you insert a record into a table that contains an AUTO_INCREMENT column, you can obtain the value stored into that column by calling the mysql_insert_id() function.

You can check from your C applications whether a value was stored in an AUTO_INCREMENT column by executing the following code (which assumes that you've checked that the statement succeeded). It determines whether the query was an INSERT with an AUTO_INCREMENT index: 

if ((result = mysql_store_result(&mysql)) == 0 &&
 mysql_field_count(&mysql) == 0 &&
 mysql_insert_id(&mysql) != 0)
{
 used_id = mysql_insert_id(&mysql);
}

When a new AUTO_INCREMENT value has been generated, you can also obtain it by executing a SELECT LAST_INSERT_ID() statement with mysql_query() and retrieving the value from the result set returned by the statement.

When inserting multiple values, the last automatically incremented value is returned.

For LAST_INSERT_ID(), the most recently generated ID is maintained in the server on a per-connection basis. It is not changed by another client. It is not even changed if you update another AUTO_INCREMENT column with a nonmagic value (that is, a value that is not NULL and not 0). Using LAST_INSERT_ID() and AUTO_INCREMENT columns simultaneously from multiple clients is perfectly valid. Each client will receive the last inserted ID for the last statement that client executed.

If you want to use the ID that was generated for one table and insert it into a second table, you can use SQL statements like this: 

INSERT INTO foo (auto,text)
 VALUES(NULL,'text'); # generate ID by inserting NULL INSERT INTO foo2 (id,text)
 VALUES(LAST_INSERT_ID(),'text'); # use ID in second table

Note that mysql_insert_id() returns the value stored into an AUTO_INCREMENT column, whether that value is automatically generated by storing NULL or 0 or was specified as an explicit value. LAST_INSERT_ID() returns only automatically generated AUTO_INCREMENT values. If you store an explicit value other than NULL or 0, it does not affect the value returned by LAST_INSERT_ID().

For more information on obtaining the last ID in an AUTO_INCREMENT column:

Controlling Automatic Reconnection Behavior

The MariaDB client library can perform an automatic reconnection to the server if it finds that the connection is down when you attempt to send a statement to the server to be executed. In this case, the library tries once to reconnect to the server and send the statement again.

In MariaDB 5.6, auto-reconnect is disabled by default.

If it is important for your application to know that the connection has been dropped (so that is can exit or take action to adjust for the loss of state information), be sure that auto-reconnect is disabled. To ensure this, call mysql_options() with the MYSQL_OPT_RECONNECT option: 

my_bool reconnect = 0;
mysql_options(&mysql, MYSQL_OPT_RECONNECT, &reconnect);

If the connection has gone down, the effect of mysql_ping() depends on the auto-reconnect state. If auto-reconnect is enabled, mysql_ping() performs a reconnect. Otherwise, it returns an error.

Some client programs might provide the capability of controlling automatic reconnection. For example, mysql reconnects by default, but the --skip-reconnect option can be used to suppress this behavior.

If an automatic reconnection does occur (for example, as a result of calling mysql_ping()), there is no explicit indication of it. To check for reconnection, call mysql-thread-id() to get the original connection identifier before calling mysql_ping(), then call mysql_thread_id() again to see whether the identifier has changed.

Automatic reconnection can be convenient because you need not implement your own reconnect code, but if a reconnection does occur, several aspects of the connection state are reset on the server side and your application will not know about it. The connection-related state is affected as follows:

If the connection drops, it is possible that the session associated with the connection on the server side will still be running if the server has not yet detected that the client is no longer connected. In this case, any locks held by the original connection still belong to that session, so you may want to kill it by calling mysql_kill().

C API Support for Multiple Statement Execution

By default, mysql-query() and mysql_real_query() interpret their statement string argument as a single statement to be executed, and you process the result according to whether the statement produces a result set (a set of rows, as for SELECT) or an affected-rows count (as for INSERT, UPDATE, and so forth).

MySQL 5.6 also supports the execution of a string containing multiple statements separated by semicolon (";") characters. This capability is enabled by special options that are specified either when you connect to the server with mysql_real_connect() or after connecting by calling` mysql_set_server_option().

Executing a multiple-statement string can produce multiple result sets or row-count indicators. Processing these results involves a different approach than for the single-statement case: After handling the result from the first statement, it is necessary to check whether more results exist and process them in turn if so. To support multiple-result processing, the C API includes the mysql_more_results() and mysql_next_result() functions. These functions are used at the end of a loop that iterates as long as more results are available. Failure to process the result this way may result in a dropped connection to the server.

Multiple-result processing also is required if you execute CALL statements for stored procedures. Results from a stored procedure have these characteristics:

The multiple statement and result capabilities can be used only with mysql-query() or mysql_real_query(). They cannot be used with the prepared statement interface. Prepared statement handles are defined to work only with strings that contain a single statement. See , "C API Prepared Statements".

To enable multiple-statement execution and result processing, the following options may be used:

The following procedure outlines a suggested strategy for handling multiple statements:

  1. Pass CLIENT_MULTI_STATEMENTS to mysql_real_connect(), to fully enable multiple-statement execution and multiple-result processing.
  2. After calling mysql-query() or mysql_real_query() and verifying that it succeeds, enter a loop within which you process statement results.
  3. For each iteration of the loop, handle the current statement result, retrieving either a result set or an affected-rows count. If an error occurs, exit the loop.
  4. At the end of the loop, call mysql_next_result() to check whether another result exists and initiate retrieval for it if so. If no more results are available, exit the loop.

One possible implementation of the preceding strategy is shown following. The final part of the loop can be reduced to a simple test of whether mysql_next_result() returns nonzero. The code as written distinguishes between no more results and an error, which enables a message to be printed for the latter occurrence. 

/* connect to server with the CLIENT_MULTI_STATEMENTS option */
if (mysql_real_connect (mysql, host_name, user_name, password,
 db_name, port_num, socket_name, CLIENT_MULTI_STATEMENTS) == NULL)
{
 printf('mysql_real_connect() failed\n');
 mysql_close(mysql);
 exit(1);
}
/* execute multiple statements */
status = mysql_query(mysql,
 'DROP TABLE IF EXISTS test_table;\
 CREATE TABLE test_table(id INT);\
 INSERT INTO test_table VALUES(10);\
 UPDATE test_table SET id=20 WHERE id=10;\
 SELECT * FROM test_table;\
 DROP TABLE test_table');
if (status)
{
 printf('Could not execute statement(s)');
 mysql_close(mysql);
 exit(0);
}
/* process each statement result */
do {
 /* did current statement return data? */
 result = mysql_store_result(mysql);
 if (result)
 {
 /* yes; process rows and free the result set */
 process_result_set(mysql, result);
 mysql_free_result(result);
 }
 else /* no result set or error */
 {
 if (mysql_field_count(mysql) == 0)
 {
 printf('%lld rows affected\n',
 mysql_affected_rows(mysql));
 }
 else /* some error occurred */
 {
 printf('Could not retrieve result set\n');
 break;
 }
 }
 /* more results? -1 = no, >0 = error, 0 = yes (keep looping) */
 if ((status = mysql_next_result(mysql)) > 0)
 printf('Could not execute statement\n');
} while (status == 0);
mysql_close(mysql);

C API Prepared Statement Problems

Here follows a list of the currently known problems with prepared statements:

C API Prepared Statement Handling of Date and Time Values

The binary (prepared statement) protocol enables you to send and receive date and time values (DATE, TIME, DATETIME, and TIMESTAMP), using the MYSQL_TIME structure. The members of this structure are described in , "C API Prepared Statement Data Structures".

To send temporal data values, create a prepared statement using mysql_stmt_prepare(). Then, before calling mysql_stmt_execute() to execute the statement, use the following procedure to set up each temporal parameter:

  1. In the MYSQL_BIND structure associated with the data value, set the buffer_type member to the type that indicates what kind of temporal value you're sending. For DATE, TIME, DATETIME, or TIMESTAMP values, set buffer_type to MYSQL_TYPE_DATE, MYSQL_TYPE_TIME, MYSQL_TYPE_DATETIME, or MYSQL_TYPE_TIMESTAMP, respectively.
  2. Set the buffer member of the MYSQL_BIND structure to the address of the MYSQL_TIME structure in which you pass the temporal value.
  3. Fill in the members of the MYSQL_TIME structure that are appropriate for the type of temporal value to be passed.

Use mysql_stmt_bind_param() to bind the parameter data to the statement. Then you can call mysql_stmt_execute().

To retrieve temporal values, the procedure is similar, except that you set the buffer_type member to the type of value you expect to receive, and the buffer member to the address of a MYSQL_TIME structure into which the returned value should be placed. Use mysql_stmt_bind_result() to bind the buffers to the statement after calling mysql_stmt_execute() and before fetching the results.

Here is a simple example that inserts DATE, TIME, and TIMESTAMP data. The MariaDB variable is assumed to be a valid connection handle. 

 MYSQL_TIME ts;
 MYSQL_BIND bind[3];
 MYSQL_STMT *stmt;
 strmov(query, 'INSERT INTO test_table(date_field, time_field, \
 timestamp_field) VALUES(?,?,?');
 stmt = mysql_stmt_init(mysql);
 if (!stmt)
 {
 fprintf(stderr, ' mysql_stmt_init(), out of memory\n');
 exit(0);
 }
 if (mysql_stmt_prepare(mysql, query, strlen(query)))
 {
 fprintf(stderr, '\n mysql_stmt_prepare(), INSERT failed');
 fprintf(stderr, '\n %s', mysql_stmt_error(stmt));
 exit(0);
 }
 /* set up input buffers for all 3 parameters */
 bind[0].buffer_type= MYSQL_TYPE_DATE;
 bind[0].buffer= (char *)&ts;
 bind[0].is_null= 0;
 bind[0].length= 0;
 ...
 bind[1]= bind[2]= bind[0];
 ...
 mysql_stmt_bind_param(stmt, bind);
 /* supply the data to be sent in the ts structure */
 ts.year= 2002;
 ts.month= 02;
 ts.day= 03;
 ts.hour= 10;
 ts.minute= 45;
 ts.second= 20;
 mysql_stmt_execute(stmt);
 ..

C API Support for Prepared CALL Statements

This section describes prepared-statement support in the C API for stored procedures executed using CALL statements:

In MariaDB 5.6, stored procedures executed using prepared CALL statements can be used in the following ways:

The following discussion shows how to use these capabilities through the C API for prepared statements. To use prepared CALL statements through the PREPARE and EXECUTE statements, see , "CALL Syntax".

If an application might be compiled or executed in a context where a version of MariaDB older than 5.5.3 is used, prepared CALL capabilities for multiple result sets and OUT or INOUT parameters might not be available:

An application that executes a prepared CALL statement should use a loop that fetches a result and then invokes mysql_stmt_next_result() to determine whether there are more results. The results consist of any result sets produced by the stored procedure followed by a final status value that indicates whether the procedure terminated successfully.

If the procedure has OUT or INOUT parameters, the result set preceding the final status value contains their values. To determine whether a result set contains parameter values, test whether the SERVER_PS_OUT_PARAMS bit is set in the server_status member of the MariaDB connection handler: 

mysql->server_status & SERVER_PS_OUT_PARAMS

The following example uses a prepared CALL statement to execute a stored procedure that produces multiple result sets and that provides parameter values back to the caller by means of OUT and INOUT parameters. The procedure takes parameters of all three types (IN, OUT, INOUT), displays their initial values, assigns new values, displays the updated values, and returns. The expected return information from the procedure therefore consists of multiple result sets and a final status:

The code to execute the procedure: 

MYSQL_STMT *stmt;
MYSQL_BIND ps_params[3]; /* input parameter buffers */
int int_data[3]; /* input/output values */
my_bool is_null[3]; /* output value nullability */
int status;
/* set up stored procedure */
status = mysql_query(mysql, 'DROP PROCEDURE IF EXISTS p1');
test_error(mysql, status);
status = mysql_query(mysql,
 'CREATE PROCEDURE p1('
 ' IN p_in INT, '
 ' OUT p_out INT, '
 ' INOUT p_inout INT) '
 'BEGIN '
 ' SELECT p_in, p_out, p_inout; '
 ' SET p_in = 100, p_out = 200, p_inout = 300; '
 ' SELECT p_in, p_out, p_inout; '
 'END');
test_error(mysql, status);
/* initialize and prepare CALL statement with parameter placeholders */
stmt = mysql_stmt_init(mysql);
if (!stmt)
{
 printf('Could not initialize statement\n');
 exit(1);
}
status = mysql_stmt_prepare(stmt, 'CALL p1(?, ?, ?)', 16);
test_stmt_error(stmt, status);
/* initialize parameters: p_in, p_out, p_inout (all INT) */
memset(ps_params, 0, sizeof (ps_params));
ps_params[0].buffer_type = MYSQL_TYPE_LONG;
ps_params[0].buffer = (char *) &int_data[0];
ps_params[0].length = 0;
ps_params[0].is_null = 0;
ps_params[1].buffer_type = MYSQL_TYPE_LONG;
ps_params[1].buffer = (char *) &int_data[1];
ps_params[1].length = 0;
ps_params[1].is_null = 0;
ps_params[2].buffer_type = MYSQL_TYPE_LONG;
ps_params[2].buffer = (char *) &int_data[2];
ps_params[2].length = 0;
ps_params[2].is_null = 0;
/* bind parameters */
status = mysql_stmt_bind_param(stmt, ps_params);
test_stmt_error(stmt, status);
/* assign values to parameters and execute statement */
int_data[0]= 10; /* p_in */
int_data[1]= 20; /* p_out */
int_data[2]= 30; /* p_inout */
status = mysql_stmt_execute(stmt);
test_stmt_error(stmt, status);
/* process results until there are no more */
do {
 int i;
 int num_fields; /* number of columns in result */
 MYSQL_FIELD *fields; /* for result set metadata */
 MYSQL_BIND *rs_bind; /* for output buffers */
 /* the column count is > 0 if there is a result set */
 /* 0 if the result is only the final status packet */
 num_fields = mysql_stmt_field_count(stmt);
 if (num_fields > 0)
 {
 /* there is a result set to fetch */
 printf('Number of columns in result: %d\n', (int) num_fields);
 /* what kind of result set is this? */
 printf('Data: ');
 if(mysql->server_status & SERVER_PS_OUT_PARAMS)
 printf('this result set contains OUT/INOUT parameters\n');
 else
 printf('this result set is produced by the procedure\n');
 MYSQL_RES *rs_metadata = mysql_stmt_result_metadata(stmt);
 test_stmt_error(stmt, rs_metadata == NULL);
 fields = mysql_fetch_fields(rs_metadata);
 rs_bind = (MYSQL_BIND *) malloc(sizeof (MYSQL_BIND) * num_fields);
 if (!rs_bind)
 {
 printf('Cannot allocate output buffers\n');
 exit(1);
 }
 memset(rs_bind, 0, sizeof (MYSQL_BIND) * num_fields);
 /* set up and bind result set output buffers */
 for (i = 0; i < num_fields; ++i)
 {
 rs_bind[i].buffer_type = fields[i].type;
 rs_bind[i].is_null = &is_null[i];
 switch (fields[i].type)
 {
 case MYSQL_TYPE_LONG:
 rs_bind[i].buffer = (char *) &(int_data[i]);
 rs_bind[i].buffer_length = sizeof (int_data);
 break;
 default:
 fprintf(stderr, 'ERROR: unexpected type: %d.\n', fields[i].type);
 exit(1);
 }
 }
 status = mysql_stmt_bind_result(stmt, rs_bind);
 test_stmt_error(stmt, status);
 /* fetch and display result set rows */
 while (1)
 {
 status = mysql_stmt_fetch(stmt);
 if (status == 1 || status == MYSQL_NO_DATA)
 break;
 for (i = 0; i < num_fields; ++i)
 {
 switch (rs_bind[i].buffer_type)
 {
 case MYSQL_TYPE_LONG:
 if (*rs_bind[i].is_null)
 printf(' val[%d] = NULL;', i);
 else
 printf(' val[%d] = %ld;',
 i, (long) *((int *) rs_bind[i].buffer));
 break;
 default:
 printf(' unexpected type (%d)\n',
 rs_bind[i].buffer_type);
 }
 }
 printf('\n');
 }
 mysql_free_result(rs_metadata); /* free metadata */
 free(rs_bind); /* free output buffers */
 }
 else
 {
 /* no columns = final status packet */
 printf('End of procedure output\n');
 }
 /* more results? -1 = no, >0 = error, 0 = yes (keep looking) */
 status = mysql_stmt_next_result(stmt);
 if (status > 0)
 test_stmt_error(stmt, status);
} while (status == 0);
mysql_stmt_close(stmt);

Execution of the procedure should produce the following output: 

Number of columns in result: 3
Data: this result set is produced by the procedure
 val[0] = 10; val[1] = NULL; val[2] = 30;
Number of columns in result: 3
Data: this result set is produced by the procedure
 val[0] = 100; val[1] = 200; val[2] = 300;
Number of columns in result: 2
Data: this result set contains OUT/INOUT parameters
 val[0] = 200; val[1] = 300;
End of procedure output

The code uses two utility routines, test_error() test_stmt_error(), to check for errors and terminate after printing diagnostic information if an error occurred: 

static void test_error(MYSQL *mysql, int status)
{
 if (status)
 {
 fprintf(stderr, 'Error: %s (errno: %d)\n',
 mysql_error(mysql), mysql_errno(mysql));
 exit(1);
 }
}
static void test_stmt_error(MYSQL_STMT *stmt, int status)
{
 if (status)
 {
 fprintf(stderr, 'Error: %s (errno: %d)\n',
 mysql_stmt_error(stmt), mysql_stmt_errno(stmt));
 exit(1);
 }
}

Building Client Programs

Problems Linking to the MariaDB Client Library
How to Write a Threaded Client

If you compile MariaDB clients that you've written yourself or that you obtain from a third-party, they must be linked using the -lmysqlclient -lz options in the link command. You may also need to specify a -L option to tell the linker where to find the library. For example, if the library is installed in /usr/local/mysql/lib, use -L/usr/local/mysql/lib -lmysqlclient -lz in the link command.

For clients that use MariaDB header files, you may need to specify an -I option when you compile them (for example, -I/usr/local/mysql/include), so that the compiler can find the header files.

Compiling MariaDB Clients on Unix

To make it simpler to compile MariaDB programs on Unix, we have provided the mysql_config script for you. See , "mysql_config - Get Compile Options for Compiling Clients".

You can use it to compile a MariaDB client as follows: 

CFG=/usr/local/mysql/bin/mysql_config sh -c 'gcc -o progname `$CFG --cflags` progname.c `$CFG --libs`'

The sh -c is needed to get the shell not to treat the output from mysql_config as one word.

Compiling MariaDB Clients on Microsoft Windows

On Windows, you can link your code with either the dynamic or static client library. The static library is named mysqlclient and the dynamic library is named libmysql.

If you link with the static library, failure can occur if certain conditions are not satisfied:

If the client application is built in in debug mode and uses the static debug C runtime (/MTd compiler option), it can link the mysqlclient if that library was built using the same option. If the client application uses the dynamic C runtime (/MD option, or /MDd option in debug mode), it cannot link with the static client library and must use the dynamic library.

The MSDN page describing the link options can be found here: http://msdn.microsoft.com/en-us/library/2kzt1wy3.aspx

Problems Linking to the MariaDB Client Library

When linking with the C API, the following errors may occur on some systems: 

gcc -g -o client test.o -L/usr/local/lib/mysql \
 -lmysqlclient -lsocket -lnsl Undefined first referenced
 symbol in file floor /usr/local/lib/mysql/libmysqlclient.a(password.o)
ld: fatal: Symbol referencing errors. No output written to client

If this happens on your system, you must include the math library by adding -lm to the end of the compile/link line.

When you are linking an application program to use the MariaDB client library, you might get undefined reference errors for symbols that start with mysql_, such as those shown here: 

/tmp/ccFKsdPa.o: In function `main':
/tmp/ccFKsdPa.o(.text+0xb): undefined reference to `mysql_init'
/tmp/ccFKsdPa.o(.text+0x31): undefined reference to `mysql_real_connect'
/tmp/ccFKsdPa.o(.text+0x57): undefined reference to `mysql_real_connect'
/tmp/ccFKsdPa.o(.text+0x69): undefined reference to `mysql_error'
/tmp/ccFKsdPa.o(.text+0x9a): undefined reference to `mysql_close'

You should be able to solve this problem by adding -Ldir_path -lmysqlclient at the end of your link command, where dir_path represents the path name of the directory where the client library is located. To determine the correct directory, try this command: 

shell> mysql_config --libs

The output from mysql_config might indicate other libraries that should be specified on the link command as well.

If you get undefined reference errors for the uncompress or compress function, add -lz to the end of your link command and try again.

If you get undefined reference errors for a function that should exist on your system, such as connect, check the manual page for the function in question to determine which libraries you should add to the link command.

You might get undefined reference errors such as the following for functions that don't exist on your system: 

mf_format.o(.text+0x201): undefined reference to `__lxstat'

This usually means that your MariaDB client library was compiled on a system that is not 100% compatible with yours. In this case, you should download the latest MariaDB source distribution and compile MariaDB yourself. See , "Installing MariaDB from Source".

You might get undefined reference errors at runtime when you try to execute a MariaDB program. If these errors specify symbols that start with mysql_ or indicate that the mysqlclient library can't be found, it means that your system can't find the shared libmysqlclient.so library. The fix for this is to tell your system to search for shared libraries where the library is located. Use whichever of the following methods is appropriate for your system:

How to Write a Threaded Client

The client library is almost thread-safe. The biggest problem is that the subroutines in net.c that read from sockets are not interrupt safe. This was done with the thought that you might want to have your own alarm that can break a long read to a server. If you install interrupt handlers for the SIGPIPE interrupt, the socket handling should be thread-safe.

To avoid aborting the program when a connection terminates, MariaDB blocks SIGPIPE on the first call to mysql_library_init(), mysql-init(), or mysql_connect(). If you want to use your own SIGPIPE handler, you should first call mysql_library_init() and then install your handler.

If "undefined symbol" errors occur when linking against the libmysqlclient client library, in most cases this is because you have not included the thread libraries on the link/compile command.

The client library is thread-safe per connection. You can let two threads share the same connection with the following caveats:

You need to know the following if you have a thread that did not create the connection to the MariaDB database but is calling MariaDB functions:

When you call mysql_init(), MariaDB creates a thread-specific variable for the thread that is used by the debug library (among other things). If you call a MariaDB function before the thread has called mysql_init(), the thread does not have the necessary thread-specific variables in place and you are likely to end up with a core dump sooner or later. To avoid problems, you must do the following:

  1. Call mysql_library_init() before any other MariaDB functions. It is not thread-safe, so call it before threads are created, or protect the call with a mutex.
  2. Arrange for mysql_thread_init() to be called early in the thread handler before calling any MariaDB function. If you call mysql_init(), it will call mysql_thread_init() for you.
  3. In the thread, call mysql_thread_end() before calling pthread_exit(). This frees the memory used by MariaDB thread-specific variables.

The preceding notes regarding mysql-init() also apply to mysql_connect(), which calls mysql_init().

MySQL PHP API

Original MariaDB API (MariaDB)
MySQL Improved Extension (Mysqli)
MySQL Native Driver (Mysqlnd)
MySQL Functions (PDO_MYSQL) (MySQL (PDO))
Connector/PHP
Common Problems with MariaDB and PHP
Enabling Both MariaDB and mysqli in PHP

PHP is a server-side, HTML-embedded scripting language that may be used to create dynamic Web pages. It is available for most operating systems and Web servers, and can access most common databases, including MySQL. PHP may be run as a separate program or compiled as a module for use with the Apache Web server.

PHP provides three different MariaDB API extensions:

If you're experiencing problems with enabling both the MariaDB and the mysqli extension when building PHP on Linux yourself, see , "Enabling Both MariaDB and mysqli in PHP".

The PHP distribution and documentation are available from the PHP Web site.

Portions of this section are Copyright (c) 1997-2008 the PHP Documentation Group This material may be distributed only subject to the terms and conditions set forth in the Creative Commons Attribution 3.0 License or later. A copy of the Creative Commons Attribution 3.0 license is distributed with this manual. The latest version is presently available at This material may be distributed only subject to the terms and conditio\ ns set forth in the Open Publication License, v1.0.8 or later (the latest version is presently available at http://www.opencontent.org/openpub/).

Original MariaDB API (MariaDB)

Installing/Configuring
Predefined Constants
Examples
MySQL Functions

These functions allow you to access MariaDB database servers. More information about MariaDB can be found at http://www.mysql.com/.

Documentation for MariaDB can be found at http://dev.mysql.com/doc/.

For an overview of MariaDB database connectivity terms and products see , "Overview".

Installing/Configuring

Requirements
Installation
Runtime Configuration
Resource Types
Requirements

In order to have these functions available, you must compile PHP with MariaDB support.

Installation
Installation on Linux Systems
Installation on Windows Systems
MySQL Installation Notes

For compiling, simply use the --with-mysql[=DIR] configuration option where the optional [DIR] points to the MariaDB installation directory.

Although this MariaDB extension is compatible with MariaDB 4.1.0 and greater, it doesn't support the extra functionality that these versions provide. For that, use the MySQLi extension.

If you would like to install the mysql extension along with the mysqli extension you have to use the same client library to avoid any conflicts.

Installation on Linux Systems

Note: [DIR] is the path to the MariaDB client library files (headers and libraries), which can be downloaded from MySQL.

Table 20.8. ext/mysql compile time support matrix

PHP Version Default Configure Options: mysqlnd Configure Options: libmysql Changelog
4.x.x libmysql Not Available --without-mysql to disable MySQL enabled by default, MariaDB client libraries are bundled
5.0.x, 5.1.x, 5.2.x libmysql Not Available --with-mysql=[DIR] MySQL is no longer enabled by default, and the MariaDB client libraries are no longer bundled
5.3.x libmysql --with-mysql=mysqlnd --with-mysql=[DIR] mysqlnd is now available
5.4.x mysqlnd --with-mysql --with-mysql=[DIR] mysqlnd is now the default
Installation on Windows Systems
PHP 4
PHP 5.0.x, 5.1.x, 5.2.x
PHP 5.3.0+
PHP 4

The PHP MariaDB extension is compiled into PHP.

PHP 5.0.x, 5.1.x, 5.2.x

MySQL is no longer enabled by default, so the php_mysql.dll DLL must be enabled inside of php.ini. Also, PHP needs access to the MariaDB client library. A file named libmysql.dll is included in the Windows PHP distribution and in order for PHP to talk to MariaDB this file needs to be available to the Windows systems PATH. See the FAQ titled 'How do I add my PHP directory to the PATH on Windows' for information on how to do this. Although copying libmysql.dll to the Windows system directory also works (because the system directory is by default in the system's PATH), it's not recommended.

As with enabling any PHP extension (such as php_mysql.dll), the PHP directive extension_dir should be set to the directory where the PHP extensions are located. See also the Manual Windows Installation Instructions. An example extension_dir value for PHP 5 is c:\php\extNote

If when starting the web server an error similar to the following occurs: 'Unable to load dynamic library './php_mysql.dll'', this is because php_mysql.dll and/or libmysql.dll cannot be found by the system.

PHP 5.3.0+

The MySQL Native Driver is enabled by default. Include php_mysql.dll, but libmysql.dll is no longer required or used.

MySQL Installation Notes
Warning

Crashes and startup problems of PHP may be encountered when loading this extension in conjunction with the recode extension. See the recode extension for more information.Note

If you need charsets other than latin (default), you have to install external (not bundled) libmysql with compiled charset support.

Runtime Configuration

The behaviour of these functions is affected by settings in php.ini.

Table 20.9. MariaDB Configuration Options

Name Default Changeable Changelog
mysql.allow_local_infile '1' PHP_INI_SYSTEM
mysql.allow_persistent '1' PHP_INI_SYSTEM
mysql.max_persistent '-1' PHP_INI_SYSTEM
mysql.max_links '-1' PHP_INI_SYSTEM
mysql.trace_mode '0' PHP_INI_ALL Available since PHP 4.3.0.
mysql.default_port NULL PHP_INI_ALL
mysql.default_socket NULL PHP_INI_ALL Available since PHP 4.0.1.
mysql.default_host NULL PHP_INI_ALL
mysql.default_user NULL PHP_INI_ALL
mysql.default_password NULL PHP_INI_ALL
mysql.connect_timeout '60' PHP_INI_ALL PHP_INI_SYSTEM in PHP <= 4.3.2. Available since PHP 4.3.0.

For further details and definitions of the PHP_INI_* modes, see the http://www.php.net/manual/en/configuration.changes.modes.

Here's a short explanation of the configuration directives.

mysql.allow_local_infile integer

Allow accessing, from PHP's perspective, local files with LOAD DATA statements

mysql.allow_persistent boolean

Whether to allow persistent connections to MariaDB.

mysql.max_persistent integer

The maximum number of persistent MariaDB connections per process.

mysql.max_links integer

The maximum number of MariaDB connections per process, including persistent connections.

mysql.trace_mode boolean

Trace mode. When mysql.trace_mode is enabled, warnings for table/index scans, non free result sets, and SQL-Errors will be displayed. (Introduced in PHP 4.3.0)

mysql.default_port string

The default TCP port number to use when connecting to the database server if no other port is specified. If no default is specified, the port will be obtained from the MYSQL_TCP_PORT environment variable, the mysql-tcp entry in /etc/services or the compile-time MYSQL_PORT constant, in that order. Win32 will only use the MYSQL_PORT constant.

mysql.default_socket string

The default socket name to use when connecting to a local database server if no other socket name is specified.

mysql.default_host string

The default server host to use when connecting to the database server if no other host is specified. Doesn't apply in SQL safe mode.

mysql.default_user string

The default user name to use when connecting to the database server if no other name is specified. Doesn't apply in SQL safe mode.

mysql.default_password string

The default password to use when connecting to the database server if no other password is specified. Doesn't apply in SQL safe mode.

mysql.connect_timeout integer

Connect timeout in seconds. On Linux this timeout is also used for waiting for the first answer from the server.

Resource Types

There are two resource types used in the MariaDB module. The first one is the link identifier for a database connection, the second a resource which holds the result of a query.

Predefined Constants

The constants below are defined by this extension, and will only be available when the extension has either been compiled into PHP or dynamically loaded at runtime.

Since PHP 4.3.0 it is possible to specify additional client flags for the mysql_connect and mysql_pconnect functions. The following constants are defined:

Table 20.10. MariaDB client constants

Constant Description
MYSQL_CLIENT_COMPRESS Use compression protocol
MYSQL_CLIENT_IGNORE_SPACE Allow space after function names
MYSQL_CLIENT_INTERACTIVE Allow interactive_timeout seconds (instead of wait_timeout) of inactivity before closing the connection.
MYSQL_CLIENT_SSL Use SSL encryption. This flag is only available with version 4.x of the MariaDB client library or newer. Version 3.23.x is bundled both with PHP 4 and Windows binaries of PHP 5.

The function mysql_fetch_array uses a constant for the different types of result arrays. The following constants are defined:

Table 20.11. MariaDB fetch constants

Constant Description
MYSQL_ASSOC Columns are returned into the array having the fieldname as the array index.
MYSQL_BOTH Columns are returned into the array having both a numerical index and the fieldname as the array index.
MYSQL_NUM Columns are returned into the array having a numerical index to the fields. This index starts with 0, the first field in the result.

Examples

MySQL extension overview example
MySQL extension overview example

This simple example shows how to connect, execute a query, print resulting rows and disconnect from a MariaDB database.

Example 20.15. MariaDB extension overview example

<?php
// Connecting, selecting database
$link = mysql_connect('mysql_host', 'mysql_user', 'mysql_password')
 or die('Could not connect: ' . mysql_error());
echo 'Connected successfully';
mysql_select_db('my_database') or die('Could not select database');
// Performing SQL query
$query = 'SELECT * FROM my_table';
$result = mysql_query($query) or die('Query failed: ' . mysql_error());
// Printing results in HTML echo '<table>\n';
while ($line = mysql_fetch_array($result, MYSQL_ASSOC)) {
 echo '\t<tr>\n';
 foreach ($line as $col_value) {
 echo '\t\t<td>$col_value</td>\n';
 }
 echo '\t</tr>\n';
}
echo '</table>\n';
// Free resultset mysql_free_result($result);
// Closing connection mysql_close($link);
?>

MySQL Functions

mysql_affected_rows
mysql_client_encoding
mysql_close
mysql_connect
mysql_create_db
mysql_data_seek
mysql_db_name
mysql_db_query
mysql_drop_db
mysql_errno
mysql_error
mysql_escape_string
mysql_fetch_array
mysql_fetch_assoc
mysql_fetch_field
mysql_fetch_lengths
mysql_fetch_object
mysql_fetch_row
mysql_field_flags
mysql_field_len
mysql_field_name
mysql_field_seek
mysql_field_table
mysql_field_type
mysql_free_result
mysql_get_client_info
mysql_get_host_info
mysql_get_proto_info
mysql_get_server_info
mysql_info
mysql_insert_id
mysql_list_dbs
mysql_list_fields
mysql_list_processes
mysql_list_tables
mysql_num_fields
mysql_num_rows
mysql_pconnect
mysql_ping
mysql_query
mysql_real_escape_string
mysql_result
mysql_select_db
mysql_set_charset
mysql_stat
mysql_tablename
mysql_thread_id
mysql_unbuffered_query
Note

Most MariaDB functions accept link_identifier as the last optional parameter. If it is not provided, last opened connection is used. If it doesn't exist, connection is tried to establish with default parameters defined in php.ini. If it is not successful, functions return FALSE .

mysql_affected_rows

Description

int mysql_affected_rows(resource link_identifier= =NULL);

Get the number of affected rows by the last INSERT, UPDATE, REPLACE or DELETE query associated with link_identifier.

Parameters

link_identifier

The MariaDB connection. If the link identifier is not specified, the last link opened by mysql_connect is assumed. If no such link is found, it will try to create one as if mysql_connect was called with no arguments. If no connection is found or established, an E_WARNING level error is generated.

Return Values

Returns the number of affected rows on success, and -1 if the last query failed.

If the last query was a DELETE query with no WHERE clause, all of the records will have been deleted from the table but this function will return zero with MariaDB versions prior to 4.1.2.

When using UPDATE, MariaDB will not update columns where the new value is the same as the old value. This creates the possibility that mysql_affected_rows may not actually equal the number of rows matched, only the number of rows that were literally affected by the query.

The REPLACE statement first deletes the record with the same primary key and then inserts the new record. This function returns the number of deleted records plus the number of inserted records.

Examples

Example 20.16. mysql_affected_rows example 

<?php
$link = mysql_connect('localhost', 'mysql_user', 'mysql_password');
if (!$link) {
 die('Could not connect: ' . mysql_error());
}
mysql_select_db('mydb');
/* this should return the correct numbers of deleted records */
mysql_query('DELETE FROM mytable WHERE id < 10');
printf('Records deleted: %d\n', mysql_affected_rows());
/* with a where clause that is never true, it should return 0 */
mysql_query('DELETE FROM mytable WHERE 0');
printf('Records deleted: %d\n', mysql_affected_rows());
?>

The above example will output something similar to: 

Records deleted: 10
Records deleted: 0

Example 20.17. mysql_affected_rows example using transactions 

<?php
$link = mysql_connect('localhost', 'mysql_user', 'mysql_password');
if (!$link) {
 die('Could not connect: ' . mysql_error());
}
mysql_select_db('mydb');
/* Update records */
mysql_query('UPDATE mytable SET used=1 WHERE id < 10');
printf ('Updated records: %d\n', mysql_affected_rows());
mysql_query('COMMIT');
?>

The above example will output something similar to: 

Updated Records: 10

Notes

Transactions

If you are using transactions, you need to call mysql_affected_rows after your INSERT, UPDATE, or DELETE query, not after the COMMIT.SELECT Statements

To retrieve the number of rows returned by a SELECT, it is possible to use mysql_num_rows.Cascaded Foreign Keys

mysql_affected_rows does not count rows affected implicitly through the use of ON DELETE CASCADE and/or ON UPDATE CASCADE in foreign key constraints.

See Also

mysql_num_rows
mysql_info
mysql_client_encoding

Description

string mysql_client_encoding(resource link_identifier= =NULL);

Retrieves the character_set variable from MySQL.

Parameters

link_identifier

The MariaDB connection. If the link identifier is not specified, the last link opened by mysql_connect is assumed. If no such link is found, it will try to create one as if mysql_connect was called with no arguments. If no connection is found or established, an E_WARNING level error is generated.

Return Values

Returns the default character set name for the current connection.

Examples

Example 20.18. mysql_client_encoding example 

<?php
$link = mysql_connect('localhost', 'mysql_user', 'mysql_password');
$charset = mysql_client_encoding($link);
echo 'The current character set is: $charset\n';
?>

The above example will output something similar to: 

The current character set is: latin1

See Also

mysql_set_charset
mysql_real_escape_string
mysql_close

Description

bool mysql_close(resource link_identifier= =NULL);

mysql_close closes the non-persistent connection to the MariaDB server that's associated with the specified link identifier. If link_identifier isn't specified, the last opened link is used.

Using mysql_close isn't usually necessary, as non-persistent open links are automatically closed at the end of the script's execution. See also freeing resources.

Parameters

link_identifier

The MariaDB connection. If the link identifier is not specified, the last link opened by mysql_connect is assumed. If no connection is found or established, an E_WARNING level error is generated.

Return Values

Returns TRUE on success or FALSE on failure.

Examples

Example 20.19. mysql_close example 

<?php
$link = mysql_connect('localhost', 'mysql_user', 'mysql_password');
if (!$link) {
 die('Could not connect: ' . mysql_error());
}
echo 'Connected successfully';
mysql_close($link);
?>

The above example will output: 

Connected successfully

Notes

Note

mysql_close will not close persistent links created by mysql_pconnect.

See Also

mysql_connect
mysql_free_result
mysql_connect

Description

resource mysql_connect(string server= =ini_get('mysql.default_host'),
string username= =ini_get('mysql.default_user'),
string password= =ini_get('mysql.default_password'),
bool new_link= =false,
int client_flags= =0);

Opens or reuses a connection to a MariaDB server.

Parameters

server

The MariaDB server. It can also include a port number. e.g. 'hostname:port' or a path to a local socket e.g. ':/path/to/socket' for the localhost.

If the PHP directive mysql.default_host is undefined (default), then the default value is 'localhost:3306'. In SQL safe mode, this parameter is ignored and value 'localhost:3306' is always used.

username

The username. Default value is defined by mysql.default_user. In SQL safe mode, this parameter is ignored and the name of the user that owns the server process is used.

password

The password. Default value is defined by mysql.default_password. In SQL safe mode, this parameter is ignored and empty password is used.

new_link

If a second call is made to mysql_connect with the same arguments, no new link will be established, but instead, the link identifier of the already opened link will be returned. The new_link parameter modifies this behavior and makes mysql_connect always open a new link, even if mysql_connect was called before with the same parameters. In SQL safe mode, this parameter is ignored.

client_flags

The client_flags parameter can be a combination of the following constants: 128 (enable LOAD DATA LOCAL handling), MYSQL_CLIENT_SSL , MYSQL_CLIENT_COMPRESS , MYSQL_CLIENT_IGNORE_SPACE or MYSQL_CLIENT_INTERACTIVE . Read the section about Table 20.10, "MySQL client constants" for further information. In SQL safe mode, this parameter is ignored.

Return Values

Returns a MariaDB link identifier on success or FALSE on failure.

Changelog

Version Description
4.3.0 Added the client_flags parameter.
4.2.0 Added the new_link parameter.

Examples

Example 20.20. mysql_connect example 

<?php
$link = mysql_connect('localhost', 'mysql_user', 'mysql_password');
if (!$link) {
 die('Could not connect: ' . mysql_error());
}
echo 'Connected successfully';
mysql_close($link);
?>

Example 20.21. mysql_connect example using hostname:port syntax 

<?php
// we connect to example.com and port 3307
$link = mysql_connect('example.com:3307', 'mysql_user', 'mysql_password');
if (!$link) {
 die('Could not connect: ' . mysql_error());
}
echo 'Connected successfully';
mysql_close($link);
// we connect to localhost at port 3307
$link = mysql_connect('127.0.0.1:3307', 'mysql_user', 'mysql_password');
if (!$link) {
 die('Could not connect: ' . mysql_error());
}
echo 'Connected successfully';
mysql_close($link);
?>

Example 20.22. mysql_connect example using ':/path/to/socket' syntax 

<?php
// we connect to localhost and socket e.g. /tmp/mysql.sock
// variant 1: omit localhost
$link = mysql_connect(':/tmp/mysql', 'mysql_user', 'mysql_password');
if (!$link) {
 die('Could not connect: ' . mysql_error());
}
echo 'Connected successfully';
mysql_close($link);
// variant 2: with localhost
$link = mysql_connect('localhost:/tmp/mysql.sock', 'mysql_user', 'mysql_password');
if (!$link) {
 die('Could not connect: ' . mysql_error());
}
echo 'Connected successfully';
mysql_close($link);
?>

Notes

Note

Whenever you specify 'localhost' or 'localhost:port' as server, the MariaDB client library will override this and try to connect to a local socket (named pipe on Windows). If you want to use TCP/IP, use '127.0.0.1' instead of 'localhost'. If the MariaDB client library tries to connect to the wrong local socket, you should set the correct path as mysql.default_host string in your PHP configuration and leave the server field blank.Note

The link to the server will be closed as soon as the execution of the script ends, unless it's closed earlier by explicitly calling mysql_close.Note

You can suppress the error message on failure by prepending a @ to the function name.Note

Error 'Can't create TCP/IP socket (10106)' usually means that the variables_order configure directive doesn't contain character E. On Windows, if the environment is not copied the SYSTEMROOT environment variable won't be available and PHP will have problems loading Winsock.

See Also

mysql_pconnect
mysql_close
mysql_create_db

Description

bool mysql_create_db(string database_name,
resource link_identifier= =NULL);

mysql_create_db attempts to create a new database on the server associated with the specified link identifier.

Parameters

database_name

The name of the database being created.

link_identifier

The MariaDB connection. If the link identifier is not specified, the last link opened by mysql_connect is assumed. If no such link is found, it will try to create one as if mysql_connect was called with no arguments. If no connection is found or established, an E_WARNING level error is generated.

Return Values

Returns TRUE on success or FALSE on failure.

Examples

Example 20.23. mysql_create_db alternative example

The function mysql_create_db is deprecated. It is preferable to use mysql_query to issue an sql CREATE DATABASE statement instead. 

<?php
$link = mysql_connect('localhost', 'mysql_user', 'mysql_password');
if (!$link) {
 die('Could not connect: ' . mysql_error());
}
$sql = 'CREATE DATABASE my_db';
if (mysql_query($sql, $link)) {
 echo 'Database my_db created successfully\n';
} else {
 echo 'Error creating database: ' . mysql_error() . '\n';
}
?>

The above example will output something similar to: 

Database my_db created successfully

Notes

Note

For backward compatibility, the following deprecated alias may be used: mysql_createdbNote

This function will not be available if the MariaDB extension was built against a MariaDB 4.x client library.

See Also

mysql_query
mysql_select_db
mysql_data_seek

Description

bool mysql_data_seek(resource result,
int row_number);

mysql_data_seek moves the internal row pointer of the MariaDB result associated with the specified result identifier to point to the specified row number. The next call to a MariaDB fetch function, such as mysql_fetch_assoc, would return that row.

row_number starts at 0. The row_number should be a value in the range from 0 to mysql_num_rows - 1. However if the result set is empty (mysql_num_rows == 0), a seek to 0 will fail with a E_WARNING and mysql_data_seek will return FALSE .

Parameters

result

The result resource that is being evaluated. This result comes from a call to mysql_query.

row_number

The desired row number of the new result pointer.

Return Values

Returns TRUE on success or FALSE on failure.

Examples

Example 20.24. mysql_data_seek example 

<?php
$link = mysql_connect('localhost', 'mysql_user', 'mysql_password');
if (!$link) {
 die('Could not connect: ' . mysql_error());
}
$db_selected = mysql_select_db('sample_db');
if (!$db_selected) {
 die('Could not select database: ' . mysql_error());
}
$query = 'SELECT last_name, first_name FROM friends';
$result = mysql_query($query);
if (!$result) {
 die('Query failed: ' . mysql_error());
}
/* fetch rows in reverse order */
for ($i = mysql_num_rows($result) - 1; $i >= 0; $i--) {
 if (!mysql_data_seek($result, $i)) {
 echo 'Cannot seek to row $i: ' . mysql_error() . '\n';
 continue;
 }
 if (!($row = mysql_fetch_assoc($result))) {
 continue;
 }
 echo $row['last_name'] . ' ' . $row['first_name'] . '<br />\n';
}
mysql_free_result($result);
?>

Notes

Note

The function mysql_data_seek can be used in conjunction only with mysql_query, not with mysql_unbuffered_query.

See Also

mysql_query
mysql_num_rows
mysql_fetch_row
mysql_fetch_assoc
mysql_fetch_array
mysql_fetch_object
mysql_db_name

Description

string mysql_db_name(resource result,
int row,
mixed field= =NULL);

Retrieve the database name from a call to mysql_list_dbs.

Parameters

result

The result pointer from a call to mysql_list_dbs.

row

The index into the result set.

field

The field name.

Return Values

Returns the database name on success, and FALSE on failure. If FALSE is returned, use mysql_error to determine the nature of the error.

Examples

Example 20.25. mysql_db_name example 

<?php error_reporting(E_ALL);
$link = mysql_connect('dbhost', 'username', 'password');
$db_list = mysql_list_dbs($link);
$i = 0;
$cnt = mysql_num_rows($db_list);
while ($i < $cnt) {
 echo mysql_db_name($db_list, $i) . '\n';
 $i++;
}
?>

Notes

Note

For backward compatibility, the following deprecated alias may be used: mysql_dbname

See Also

mysql_list_dbs
mysql_tablename
mysql_db_query

Description

resource mysql_db_query(string database,
string query,
resource link_identifier= =NULL);

mysql_db_query selects a database, and executes a query on it.Warning

This function has been DEPRECATED as of PHP 5.3.0. Relying on this feature is highly discouraged.

Parameters

database

The name of the database that will be selected.

query

The MariaDB query.

Data inside the query should be properly escaped.

link_identifier

The MariaDB connection. If the link identifier is not specified, the last link opened by mysql_connect is assumed. If no such link is found, it will try to create one as if mysql_connect was called with no arguments. If no connection is found or established, an E_WARNING level error is generated.

Return Values

Returns a positive MariaDB result resource to the query result, or FALSE on error. The function also returns TRUE / FALSE for INSERT/UPDATE/DELETE queries to indicate success/failure.

Changelog

Version Description
5.3.0 This function now throws an E_DEPRECATED notice.
4.0.6 This function is deprecated, do not use this function. Use mysql_select_db and mysql_query instead.

Examples

Example 20.26. mysql_db_query alternative example 

<?php if (!$link = mysql_connect('mysql_host', 'mysql_user', 'mysql_password')) {
 echo 'Could not connect to mysql';
 exit;
}
if (!mysql_select_db('mysql_dbname', $link)) {
 echo 'Could not select database';
 exit;
}
$sql = 'SELECT foo FROM bar WHERE id = 42';
$result = mysql_query($sql, $link);
if (!$result) {
 echo 'DB Error, could not query the database\n';
 echo 'MySQL Error: ' . mysql_error();
 exit;
}
while ($row = mysql_fetch_assoc($result)) {
 echo $row['foo'];
}
mysql_free_result($result);
?>

Notes

Note

Be aware that this function does NOT switch back to the database you were connected before. In other words, you can't use this function to temporarily run a sql query on another database, you would have to manually switch back. Users are strongly encouraged to use the database.table syntax in their sql queries or mysql_select_db instead of this function.

See Also

mysql_query
mysql_select_db
mysql_drop_db

Description

bool mysql_drop_db(string database_name,
resource link_identifier= =NULL);

mysql_drop_db attempts to drop (remove) an entire database from the server associated with the specified link identifier. This function is deprecated, it is preferable to use mysql_query to issue an sql DROP DATABASE statement instead.

Parameters

database_name

The name of the database that will be deleted.

link_identifier

The MariaDB connection. If the link identifier is not specified, the last link opened by mysql_connect is assumed. If no such link is found, it will try to create one as if mysql_connect was called with no arguments. If no connection is found or established, an E_WARNING level error is generated.

Return Values

Returns TRUE on success or FALSE on failure.

Examples

Example 20.27. mysql_drop_db alternative example 

<?php
$link = mysql_connect('localhost', 'mysql_user', 'mysql_password');
if (!$link) {
 die('Could not connect: ' . mysql_error());
}
$sql = 'DROP DATABASE my_db';
if (mysql_query($sql, $link)) {
 echo 'Database my_db was successfully dropped\n';
} else {
 echo 'Error dropping database: ' . mysql_error() . '\n';
}
?>

Notes

Warning

This function will not be available if the MariaDB extension was built against a MariaDB 4.x client library.Note

For backward compatibility, the following deprecated alias may be used: mysql_dropdb

See Also

mysql_query
mysql_errno

Description

int mysql_errno(resource link_identifier= =NULL);

Returns the error number from the last MariaDB function.

Errors coming back from the MariaDB database backend no longer issue warnings. Instead, use mysql_errno to retrieve the error code. Note that this function only returns the error code from the most recently executed MariaDB function (not including mysql_error and mysql_errno), so if you want to use it, make sure you check the value before calling another MariaDB function.

Parameters

link_identifier

The MariaDB connection. If the link identifier is not specified, the last link opened by mysql_connect is assumed. If no such link is found, it will try to create one as if mysql_connect was called with no arguments. If no connection is found or established, an E_WARNING level error is generated.

Return Values

Returns the error number from the last MariaDB function, or 0 (zero) if no error occurred.

Examples

Example 20.28. mysql_errno example 

<?php
$link = mysql_connect('localhost', 'mysql_user', 'mysql_password');
if (!mysql_select_db('nonexistentdb', $link)) {
 echo mysql_errno($link) . ': ' . mysql_error($link). '\n';
}
mysql_select_db('kossu', $link);
if (!mysql_query('SELECT * FROM nonexistenttable', $link)) {
 echo mysql_errno($link) . ': ' . mysql_error($link) . '\n';
}
?>

The above example will output something similar to: 

1049: Unknown database 'nonexistentdb'
1146: Table 'kossu.nonexistenttable' doesn't exist

See Also

mysql_error
MySQL error codes
mysql_error

Description

string mysql_error(resource link_identifier= =NULL);

Returns the error text from the last MariaDB function. Errors coming back from the MariaDB database backend no longer issue warnings. Instead, use mysql_error to retrieve the error text. Note that this function only returns the error text from the most recently executed MariaDB function (not including mysql_error and mysql_errno), so if you want to use it, make sure you check the value before calling another MariaDB function.

Parameters

link_identifier

The MariaDB connection. If the link identifier is not specified, the last link opened by mysql_connect is assumed. If no such link is found, it will try to create one as if mysql_connect was called with no arguments. If no connection is found or established, an E_WARNING level error is generated.

Return Values

Returns the error text from the last MariaDB function, or '' (empty string) if no error occurred.

Examples

Example 20.29. mysql_error example 

<?php
$link = mysql_connect('localhost', 'mysql_user', 'mysql_password');
mysql_select_db('nonexistentdb', $link);
echo mysql_errno($link) . ': ' . mysql_error($link). '\n';
mysql_select_db('kossu', $link);
mysql_query('SELECT * FROM nonexistenttable', $link);
echo mysql_errno($link) . ': ' . mysql_error($link) . '\n';
?>

The above example will output something similar to: 

1049: Unknown database 'nonexistentdb'
1146: Table 'kossu.nonexistenttable' doesn't exist

See Also

mysql_errno
MySQL error codes
mysql_escape_string

Description

string mysql_escape_string(string unescaped_string);

This function will escape the unescaped_string, so that it is safe to place it in a mysql_query. This function is deprecated.

This function is identical to mysql_real_escape_string except that mysql_real_escape_string takes a connection handler and escapes the string according to the current character set. mysql_escape_string does not take a connection argument and does not respect the current charset setting.Warning

This function has been DEPRECATED as of PHP 5.3.0. Relying on this feature is highly discouraged.

Parameters

unescaped_string

The string that is to be escaped.

Return Values

Returns the escaped string.

Changelog

Version Description
5.3.0 This function now throws an E_DEPRECATED notice.
4.3.0 This function became deprecated, do not use this function. Instead, use mysql_real_escape_string.

Examples

Example 20.30. mysql_escape_string example 

<?php
$item = 'Zak's Laptop';
$escaped_item = mysql_escape_string($item);
printf('Escaped string: %s\n', $escaped_item);
?>

The above example will output: 

Escaped string: Zak\'s Laptop

Notes

Note

mysql_escape_string does not escape % and _.

See Also

mysql_real_escape_string
addslashes
The magic_quotes_gpc directive.
mysql_fetch_array

Description

array mysql_fetch_array(resource result,
int result_type= =MYSQL_BOTH);

Returns an array that corresponds to the fetched row and moves the internal data pointer ahead.

Parameters

result

The result resource that is being evaluated. This result comes from a call to mysql_query.

result_type

The type of array that is to be fetched. It's a constant and can take the following values: MYSQL_ASSOC , MYSQL_NUM , and MYSQL_BOTH .

Return Values

Returns an array of strings that corresponds to the fetched row, or FALSE if there are no more rows. The type of returned array depends on how result_type is defined. By using MYSQL_BOTH (default), you'll get an array with both associative and number indices. Using MYSQL_ASSOC , you only get associative indices (as mysql_fetch_assoc works), using MYSQL_NUM , you only get number indices (as mysql_fetch_row works).

If two or more columns of the result have the same field names, the last column will take precedence. To access the other column(s) of the same name, you must use the numeric index of the column or make an alias for the column. For aliased columns, you cannot access the contents with the original column name.

Examples

Example 20.31. Query with aliased duplicate field names

SELECT table1.field AS foo, table2.field AS bar FROM table1, table2

Example 20.32. mysql_fetch_array with MYSQL_NUM 

<?php mysql_connect('localhost', 'mysql_user', 'mysql_password') or
 die('Could not connect: ' . mysql_error());
mysql_select_db('mydb');
$result = mysql_query('SELECT id, name FROM mytable');
while ($row = mysql_fetch_array($result, MYSQL_NUM)) {
 printf('ID: %s Name: %s', $row[0], $row[1]); 
}
mysql_free_result($result);
?>

Example 20.33. mysql_fetch_array with MYSQL_ASSOC 

<?php mysql_connect('localhost', 'mysql_user', 'mysql_password') or
 die('Could not connect: ' . mysql_error());
mysql_select_db('mydb');
$result = mysql_query('SELECT id, name FROM mytable');
while ($row = mysql_fetch_array($result, MYSQL_ASSOC)) {
 printf('ID: %s Name: %s', $row['id'], $row['name']);
}
mysql_free_result($result);
?>

Example 20.34. mysql_fetch_array with MYSQL_BOTH 

<?php mysql_connect('localhost', 'mysql_user', 'mysql_password') or
 die('Could not connect: ' . mysql_error());
mysql_select_db('mydb');
$result = mysql_query('SELECT id, name FROM mytable');
while ($row = mysql_fetch_array($result, MYSQL_BOTH)) {
 printf ('ID: %s Name: %s', $row[0], $row['name']);
}
mysql_free_result($result);
?>

Notes

Performance

An important thing to note is that using mysql_fetch_array is not significantly slower than using mysql_fetch_row, while it provides a significant added value.Note

Field names returned by this function are case-sensitive.Note

This function sets NULL fields to the PHP NULL value.

See Also

mysql_fetch_row
mysql_fetch_assoc
mysql_data_seek
mysql_query
mysql_fetch_assoc

Description

array mysql_fetch_assoc(resource result);

Returns an associative array that corresponds to the fetched row and moves the internal data pointer ahead. mysql_fetch_assoc is equivalent to calling mysql_fetch_array with MYSQL_ASSOC for the optional second parameter. It only returns an associative array.

Parameters

result

The result resource that is being evaluated. This result comes from a call to mysql_query.

Return Values

Returns an associative array of strings that corresponds to the fetched row, or FALSE if there are no more rows.

If two or more columns of the result have the same field names, the last column will take precedence. To access the other column(s) of the same name, you either need to access the result with numeric indices by using mysql_fetch_row or add alias names. See the example at the mysql_fetch_array description about aliases.

Examples

Example 20.35. An expanded mysql_fetch_assoc example 

<?php
$conn = mysql_connect('localhost', 'mysql_user', 'mysql_password');
if (!$conn) {
 echo 'Unable to connect to DB: ' . mysql_error();
 exit;
}
if (!mysql_select_db('mydbname')) {
 echo 'Unable to select mydbname: ' . mysql_error();
 exit;
}
$sql = 'SELECT id as userid, fullname, userstatus 
 FROM sometable
 WHERE userstatus = 1';
$result = mysql_query($sql);
if (!$result) {
 echo 'Could not successfully run query ($sql) from DB: ' . mysql_error();
 exit;
}
if (mysql_num_rows($result) == 0) {
 echo 'No rows found, nothing to print so am exiting';
 exit;
}
// While a row of data exists, put that row in $row as an associative array
// Note: If you're expecting just one row, no need to use a loop
// Note: If you put extract($row); inside the following loop, you'll
// then create $userid, $fullname, and $userstatus while ($row = mysql_fetch_assoc($result)) {
 echo $row['userid'];
 echo $row['fullname'];
 echo $row['userstatus'];
}
mysql_free_result($result);
?>

Notes

Performance

An important thing to note is that using mysql_fetch_assoc is not significantly slower than using mysql_fetch_row, while it provides a significant added value.Note

Field names returned by this function are case-sensitive.Note

This function sets NULL fields to the PHP NULL value.

See Also

mysql_fetch_row
mysql_fetch_array
mysql_data_seek
mysql_query
mysql_error
mysql_fetch_field

Description

object mysql_fetch_field(resource result,
int field_offset= =0);

Returns an object containing field information. This function can be used to obtain information about fields in the provided query result.

Parameters

result

The result resource that is being evaluated. This result comes from a call to mysql_query.

field_offset

The numerical field offset. If the field offset is not specified, the next field that was not yet retrieved by this function is retrieved. The field_offset starts at 0.

Return Values

Returns an object containing field information. The properties of the object are:

Examples

Example 20.36. mysql_fetch_field example 

<?php
$conn = mysql_connect('localhost', 'mysql_user', 'mysql_password');
if (!$conn) {
 die('Could not connect: ' . mysql_error());
}
mysql_select_db('database');
$result = mysql_query('select * from table');
if (!$result) {
 die('Query failed: ' . mysql_error());
}
/* get column metadata */
$i = 0;
while ($i < mysql_num_fields($result)) {
 echo 'Information for column $i:<br />\n';
 $meta = mysql_fetch_field($result, $i);
 if (!$meta) {
 echo 'No information available<br />\n';
 }
 echo '<pre>
blob: $meta->blob max_length: $meta->max_length multiple_key: $meta->multiple_key name: $meta->name not_null: $meta->not_null numeric: $meta->numeric primary_key: $meta->primary_key table: $meta->table type: $meta->type unique_key: $meta->unique_key unsigned: $meta->unsigned zerofill: $meta->zerofill
</pre>';
 $i++;
}
mysql_free_result($result);
?>

Notes

Note

Field names returned by this function are case-sensitive.

See Also

mysql_field_seek
mysql_fetch_lengths

Description

array mysql_fetch_lengths(resource result);

Returns an array that corresponds to the lengths of each field in the last row fetched by MySQL.

mysql_fetch_lengths stores the lengths of each result column in the last row returned by mysql_fetch_row, mysql_fetch_assoc, mysql_fetch_array, and mysql_fetch_object in an array, starting at offset 0.

Parameters

result

The result resource that is being evaluated. This result comes from a call to mysql_query.

Return Values

An array of lengths on success or FALSE on failure.

Examples

Example 20.37. A mysql_fetch_lengths example 

<?php
$result = mysql_query('SELECT id,email FROM people WHERE id = '42'');
if (!$result) {
 echo 'Could not run query: ' . mysql_error();
 exit;
}
$row = mysql_fetch_assoc($result);
$lengths = mysql_fetch_lengths($result);
print_r($row);
print_r($lengths);
?>

The above example will output something similar to: 

Array
(
 [id] => 42
 [email] => user@example.com
)
Array
(
 [0] => 2
 [1] => 16
)

See Also

mysql_field_len
mysql_fetch_row
strlen
mysql_fetch_object

Description

object mysql_fetch_object(resource result,
string class_name,
array params);

Returns an object with properties that correspond to the fetched row and moves the internal data pointer ahead.

Parameters

result

The result resource that is being evaluated. This result comes from a call to mysql_query.

class_name

The name of the class to instantiate, set the properties of and return. If not specified, a stdClass object is returned.

params

An optional array of parameters to pass to the constructor for class_name objects.

Return Values

Returns an object with string properties that correspond to the fetched row, or FALSE if there are no more rows.

Changelog

Version Description
5.0.0 Added the ability to return as a different object.

Examples

Example 20.38. mysql_fetch_object example 

<?php mysql_connect('hostname', 'user', 'password');
mysql_select_db('mydb');
$result = mysql_query('select * from mytable');
while ($row = mysql_fetch_object($result)) {
 echo $row->user_id;
 echo $row->fullname;
}
mysql_free_result($result);
?>

Example 20.39. mysql_fetch_object example 

<?php class foo {
 public $name;
}
mysql_connect('hostname', 'user', 'password');
mysql_select_db('mydb');
$result = mysql_query('select name from mytable limit 1');
$obj = mysql_fetch_object($result, 'foo');
var_dump($obj);
?>

Notes

Performance

Speed-wise, the function is identical to mysql_fetch_array, and almost as quick as mysql_fetch_row (the difference is insignificant).Note

mysql-fetch-object is similar to mysql_fetch_array, with one difference - an object is returned, instead of an array. Indirectly, that means that you can only access the data by the field names, and not by their offsets (numbers are illegal property names).Note

Field names returned by this function are case-sensitive.Note

This function sets NULL fields to the PHP NULL value.

See Also

mysql_fetch_array
mysql_fetch_assoc
mysql_fetch_row
mysql_data_seek
mysql_query
mysql_fetch_row

Description

array mysql_fetch_row(resource result);

Returns a numerical array that corresponds to the fetched row and moves the internal data pointer ahead.

Parameters

result

The result resource that is being evaluated. This result comes from a call to mysql_query.

Return Values

Returns an numerical array of strings that corresponds to the fetched row, or FALSE if there are no more rows.

mysql_fetch_row fetches one row of data from the result associated with the specified result identifier. The row is returned as an array. Each result column is stored in an array offset, starting at offset 0.

Examples

Example 20.40. Fetching one row with mysql_fetch_row 

<?php
$result = mysql_query('SELECT id,email FROM people WHERE id = '42'');
if (!$result) {
 echo 'Could not run query: ' . mysql_error();
 exit;
}
$row = mysql_fetch_row($result);
echo $row[0]; // 42
echo $row[1]; // the email value
?>

Notes

Note

This function sets NULL fields to the PHP NULL value.

See Also

mysql_fetch_array
mysql_fetch_assoc
mysql_fetch_object
mysql_data_seek
mysql_fetch_lengths
mysql_result
mysql_field_flags

Description

string mysql_field_flags(resource result,
int field_offset);

mysql_field_flags returns the field flags of the specified field. The flags are reported as a single word per flag separated by a single space, so that you can split the returned value using explode.

Parameters

result

The result resource that is being evaluated. This result comes from a call to mysql_query.

field_offset

The numerical field offset. The field_offset starts at 0. If field_offset does not exist, an error of level E_WARNING is also issued.

Return Values

Returns a string of flags associated with the result or FALSE on failure.

The following flags are reported, if your version of MariaDB is current enough to support them: 'not_null', 'primary_key', 'unique_key', 'multiple_key', 'blob', 'unsigned', 'zerofill', 'binary', 'enum', 'auto_increment' and 'timestamp'.

Examples

Example 20.41. A mysql_field_flags example 

<?php
$result = mysql_query('SELECT id,email FROM people WHERE id = '42'');
if (!$result) {
 echo 'Could not run query: ' . mysql_error();
 exit;
}
$flags = mysql_field_flags($result, 0);
echo $flags;
print_r(explode(' ', $flags));
?>

The above example will output something similar to: 

not_null primary_key auto_increment Array
(
 [0] => not_null
 [1] => primary_key
 [2] => auto_increment
)

Notes

Note

For backward compatibility, the following deprecated alias may be used: mysql_fieldflags

See Also

mysql_field_type
mysql_field_len
mysql_field_len

Description

int mysql_field_len(resource result,
int field_offset);

mysql_field_len returns the length of the specified field.

Parameters

result

The result resource that is being evaluated. This result comes from a call to mysql_query.

field_offset

The numerical field offset. The field_offset starts at 0. If field_offset does not exist, an error of level E_WARNING is also issued.

Return Values

The length of the specified field index on success or FALSE on failure.

Examples

Example 20.42. mysql_field_len example 

<?php
$result = mysql_query('SELECT id,email FROM people WHERE id = '42'');
if (!$result) {
 echo 'Could not run query: ' . mysql_error();
 exit;
}
// Will get the length of the id field as specified in the database
// schema. 
$length = mysql_field_len($result, 0);
echo $length;
?>

Notes

Note

For backward compatibility, the following deprecated alias may be used: mysql_fieldlen

See Also

mysql_fetch_lengths
strlen
mysql_field_name

Description

string mysql_field_name(resource result,
int field_offset);

mysql_field_name returns the name of the specified field index.

Parameters

result

The result resource that is being evaluated. This result comes from a call to mysql_query.

field_offset

The numerical field offset. The field_offset starts at 0. If field_offset does not exist, an error of level E_WARNING is also issued.

Return Values

The name of the specified field index on success or FALSE on failure.

Examples

Example 20.43. mysql_field_name example 

<?php
/* The users table consists of three fields:
 * user_id
 * username
 * password.
 */
$link = mysql_connect('localhost', 'mysql_user', 'mysql_password');
if (!$link) {
 die('Could not connect to MariaDB server: ' . mysql_error());
}
$dbname = 'mydb';
$db_selected = mysql_select_db($dbname, $link);
if (!$db_selected) {
 die('Could not set $dbname: ' . mysql_error());
}
$res = mysql_query('select * from users', $link);
echo mysql_field_name($res, 0) . '\n';
echo mysql_field_name($res, 2);
?>

The above example will output: 

user_id password

Notes

Note

Field names returned by this function are case-sensitive.Note

For backward compatibility, the following deprecated alias may be used: mysql_fieldname

See Also

mysql_field_type
mysql_field_len
mysql_field_seek

Description

bool mysql_field_seek(resource result,
int field_offset);

Seeks to the specified field offset. If the next call to mysql_fetch_field doesn't include a field offset, the field offset specified in mysql_field_seek will be returned.

Parameters

result

The result resource that is being evaluated. This result comes from a call to mysql_query.

field_offset

The numerical field offset. The field_offset starts at 0. If field_offset does not exist, an error of level E_WARNING is also issued.

Return Values

Returns TRUE on success or FALSE on failure.

See Also

mysql_fetch_field
mysql_field_table

Description

string mysql_field_table(resource result,
int field_offset);

Returns the name of the table that the specified field is in.

Parameters

result

The result resource that is being evaluated. This result comes from a call to mysql_query.

field_offset

The numerical field offset. The field_offset starts at 0. If field_offset does not exist, an error of level E_WARNING is also issued.

Return Values

The name of the table on success.

Examples

Example 20.44. A mysql_field_table example 

<?php
$query = 'SELECT account.*, country.* FROM account, country WHERE country.name = 'Portugal' AND account.country_id = country.id';
// get the result from the DB
$result = mysql_query($query);
// Lists the table name and then the field name for ($i = 0; $i < mysql_num_fields($result); ++$i) {
 $table = mysql_field_table($result, $i);
 $field = mysql_field_name($result, $i);
 echo '$table: $field\n';
}
?>

Notes

Note

For backward compatibility, the following deprecated alias may be used: mysql_fieldtable

See Also

mysql_list_tables
mysql_field_type

Description

string mysql_field_type(resource result,
int field_offset);

mysql-field-type is similar to the mysql_field_name function. The arguments are identical, but the field type is returned instead.

Parameters

result

The result resource that is being evaluated. This result comes from a call to mysql_query.

field_offset

The numerical field offset. The field_offset starts at 0. If field_offset does not exist, an error of level E_WARNING is also issued.

Return Values

The returned field type will be one of 'int', 'real', 'string', 'blob', and others as detailed in the MySQL documentation.

Examples

Example 20.45. mysql_field_type example 

<?php mysql_connect('localhost', 'mysql_username', 'mysql_password');
mysql_select_db('mysql');
$result = mysql_query('SELECT * FROM func');
$fields = mysql_num_fields($result);
$rows = mysql_num_rows($result);
$table = mysql_field_table($result, 0);
echo 'Your '' . $table . '' table has ' . $fields . ' fields and ' . $rows . ' record(s)\n';
echo 'The table has the following fields:\n';
for ($i=0; $i < $fields; $i++) {
 $type = mysql_field_type($result, $i);
 $name = mysql_field_name($result, $i);
 $len = mysql_field_len($result, $i);
 $flags = mysql_field_flags($result, $i);
 echo $type . ' ' . $name . ' ' . $len . ' ' . $flags . '\n';
}
mysql_free_result($result);
mysql_close();
?>

The above example will output something similar to: 

Your 'func' table has 4 fields and 1 record(s)
The table has the following fields:
string name 64 not_null primary_key binary int ret 1 not_null string dl 128 not_null string type 9 not_null enum

Notes

Note

For backward compatibility, the following deprecated alias may be used: mysql_fieldtype

See Also

mysql_field_name
mysql_field_len
mysql_free_result

Description

bool mysql_free_result(resource result);

mysql_free_result will free all memory associated with the result identifier result.

mysql_free_result only needs to be called if you are concerned about how much memory is being used for queries that return large result sets. All associated result memory is automatically freed at the end of the script's execution.

Parameters

result

The result resource that is being evaluated. This result comes from a call to mysql_query.

Return Values

Returns TRUE on success or FALSE on failure.

If a non-resource is used for the result, an error of level E_WARNING will be emitted. It's worth noting that mysql_query only returns a resource for SELECT, SHOW, EXPLAIN, and DESCRIBE queries.

Examples

Example 20.46. A mysql_free_result example 

<?php
$result = mysql_query('SELECT id,email FROM people WHERE id = '42'');
if (!$result) {
 echo 'Could not run query: ' . mysql_error();
 exit;
}
/* Use the result, assuming we're done with it afterwards */
$row = mysql_fetch_assoc($result);
/* Now we free up the result and continue on with our script */
mysql_free_result($result);
echo $row['id'];
echo $row['email'];
?>

Notes

Note

For backward compatibility, the following deprecated alias may be used: mysql_freeresult

See Also

mysql_query
is_resource
mysql_get_client_info

Description

string mysql_get_client_info();

mysql_get_client_info returns a string that represents the client library version.

Return Values

The MariaDB client version.

Examples

Example 20.47. mysql_get_client_info example 

<?php printf('MySQL client info: %s\n', mysql_get_client_info());
?>

The above example will output something similar to: 

MySQL client info: 3.23.39

See Also

mysql_get_host_info
mysql_get_proto_info
mysql_get_server_info
mysql_get_host_info

Description

string mysql_get_host_info(resource link_identifier= =NULL);

Describes the type of connection in use for the connection, including the server host name.

Parameters

link_identifier

The MariaDB connection. If the link identifier is not specified, the last link opened by mysql_connect is assumed. If no such link is found, it will try to create one as if mysql_connect was called with no arguments. If no connection is found or established, an E_WARNING level error is generated.

Return Values

Returns a string describing the type of MariaDB connection in use for the connection or FALSE on failure.

Examples

Example 20.48. mysql_get_host_info example 

<?php
$link = mysql_connect('localhost', 'mysql_user', 'mysql_password');
if (!$link) {
 die('Could not connect: ' . mysql_error());
}
printf('MySQL host info: %s\n', mysql_get_host_info());
?>

The above example will output something similar to: 

MySQL host info: Localhost via UNIX socket

See Also

mysql_get_client_info
mysql_get_proto_info
mysql_get_server_info
mysql_get_proto_info

Description

int mysql_get_proto_info(resource link_identifier= =NULL);

Retrieves the MariaDB protocol.

Parameters

link_identifier

The MariaDB connection. If the link identifier is not specified, the last link opened by mysql_connect is assumed. If no such link is found, it will try to create one as if mysql_connect was called with no arguments. If no connection is found or established, an E_WARNING level error is generated.

Return Values

Returns the MariaDB protocol on success or FALSE on failure.

Examples

Example 20.49. mysql_get_proto_info example 

<?php
$link = mysql_connect('localhost', 'mysql_user', 'mysql_password');
if (!$link) {
 die('Could not connect: ' . mysql_error());
}
printf('MySQL protocol version: %s\n', mysql_get_proto_info());
?>

The above example will output something similar to: 

MySQL protocol version: 10

See Also

mysql_get_client_info
mysql_get_host_info
mysql_get_server_info
mysql_get_server_info

Description

string mysql_get_server_info(resource link_identifier= =NULL);

Retrieves the MariaDB server version.

Parameters

link_identifier

The MariaDB connection. If the link identifier is not specified, the last link opened by mysql_connect is assumed. If no such link is found, it will try to create one as if mysql_connect was called with no arguments. If no connection is found or established, an E_WARNING level error is generated.

Return Values

Returns the MariaDB server version on success or FALSE on failure.

Examples

Example 20.50. mysql_get_server_info example 

<?php
$link = mysql_connect('localhost', 'mysql_user', 'mysql_password');
if (!$link) {
 die('Could not connect: ' . mysql_error());
}
printf('MySQL server version: %s\n', mysql_get_server_info());
?>

The above example will output something similar to: 

MySQL server version: 4.0.1-alpha

See Also

mysql_get_client_info
mysql_get_host_info
mysql_get_proto_info
phpversion
mysql_info

Description

string mysql_info(resource link_identifier= =NULL);

Returns detailed information about the last query.

Parameters

link_identifier

The MariaDB connection. If the link identifier is not specified, the last link opened by mysql_connect is assumed. If no such link is found, it will try to create one as if mysql_connect was called with no arguments. If no connection is found or established, an E_WARNING level error is generated.

Return Values

Returns information about the statement on success, or FALSE on failure. See the example below for which statements provide information, and what the returned value may look like. Statements that are not listed will return FALSE .

Examples

Example 20.51. Relevant MariaDB Statements

Statements that return string values. The numbers are only for illustrating purpose; their values will correspond to the query. 

INSERT INTO ... SELECT ...
String format: Records: 23 Duplicates: 0 Warnings: 0 
INSERT INTO ... VALUES (...),(...),(...)...
String format: Records: 37 Duplicates: 0 Warnings: 0 
LOAD DATA INFILE ...
String format: Records: 42 Deleted: 0 Skipped: 0 Warnings: 0 
ALTER TABLE String format: Records: 60 Duplicates: 0 Warnings: 0 
UPDATE String format: Rows matched: 65 Changed: 65 Warnings: 0

Notes

Note

mysql_info returns a non- FALSE value for the INSERT ... VALUES statement only if multiple value lists are specified in the statement.

See Also

mysql_affected_rows
mysql_insert_id
mysql_stat
mysql_insert_id

Description

int mysql_insert_id(resource link_identifier= =NULL);

Retrieves the ID generated for an AUTO_INCREMENT column by the previous query (usually INSERT).

Parameters

link_identifier

The MariaDB connection. If the link identifier is not specified, the last link opened by mysql_connect is assumed. If no such link is found, it will try to create one as if mysql_connect was called with no arguments. If no connection is found or established, an E_WARNING level error is generated.

Return Values

The ID generated for an AUTO_INCREMENT column by the previous query on success, 0 if the previous query does not generate an AUTO_INCREMENT value, or FALSE if no MariaDB connection was established.

Examples

Example 20.52. mysql_insert_id example 

<?php
$link = mysql_connect('localhost', 'mysql_user', 'mysql_password');
if (!$link) {
 die('Could not connect: ' . mysql_error());
}
mysql_select_db('mydb');
mysql_query('INSERT INTO mytable (product) values ('kossu')');
printf('Last inserted record has id %d\n', mysql_insert_id());
?>

Notes

Caution

mysql_insert_id will convert the return type of the native MariaDB C API function mysql_insert_id() to a type of long (named int in PHP). If your AUTO_INCREMENT column has a column type of BIGINT (64 bits) the conversion may result in an incorrect value. Instead, use the internal MariaDB SQL function LAST_INSERT_ID() in an SQL query. For more information about PHP's maximum integer values, please see the integer documentation.Note

Because mysql_insert_id acts on the last performed query, be sure to call mysql_insert_id immediately after the query that generates the value.Note

The value of the MariaDB SQL function LAST_INSERT_ID() always contains the most recently generated AUTO_INCREMENT value, and is not reset between queries.

See Also

mysql_query
mysql_info
mysql_list_dbs

Description

resource mysql_list_dbs(resource link_identifier= =NULL);

Returns a result pointer containing the databases available from the current mysql daemon.Warning

This function has been DEPRECATED as of PHP 5.4.0. Relying on this function is highly discouraged.

Parameters

link_identifier

The MariaDB connection. If the link identifier is not specified, the last link opened by mysql_connect is assumed. If no such link is found, it will try to create one as if mysql_connect was called with no arguments. If no connection is found or established, an E_WARNING level error is generated.

Return Values

Returns a result pointer resource on success, or FALSE on failure. Use the mysql_tablename function to traverse this result pointer, or any function for result tables, such as mysql_fetch_array.

Examples

Example 20.53. mysql_list_dbs example 

<?php
// Usage without mysql_list_dbs()
$link = mysql_connect('localhost', 'mysql_user', 'mysql_password');
$res = mysql_query('SHOW DATABASES');
while ($row = mysql_fetch_assoc($res)) {
 echo $row['Database'] . '\n';
}
// Deprecated as of PHP 5.4.0
$link = mysql_connect('localhost', 'mysql_user', 'mysql_password');
$db_list = mysql_list_dbs($link);
while ($row = mysql_fetch_object($db_list)) {
 echo $row->Database . '\n';
}
?>

The above example will output something similar to: 

database1
database2
database3

Notes

Note

For backward compatibility, the following deprecated alias may be used: mysql_listdbs

See Also

mysql_db_name
mysql_select_db
mysql_list_fields

Description

resource mysql_list_fields(string database_name,
string table_name,
resource link_identifier= =NULL);

Retrieves information about the given table name.

This function is deprecated. It is preferable to use mysql_query to issue an SQL SHOW COLUMNS FROM table [LIKE 'name'] statement instead.

Parameters

database_name

The name of the database that's being queried.

table_name

The name of the table that's being queried.

link_identifier

The MariaDB connection. If the link identifier is not specified, the last link opened by mysql_connect is assumed. If no such link is found, it will try to create one as if mysql_connect was called with no arguments. If no connection is found or established, an E_WARNING level error is generated.

Return Values

A result pointer resource on success, or FALSE on failure.

The returned result can be used with mysql_field_flags, mysql_field_len, mysql_field_name and mysql_field_type.

Examples

Example 20.54. Alternate to deprecated mysql_list_fields 

<?php
$result = mysql_query('SHOW COLUMNS FROM sometable');
if (!$result) {
 echo 'Could not run query: ' . mysql_error();
 exit;
}
if (mysql_num_rows($result) > 0) {
 while ($row = mysql_fetch_assoc($result)) {
 print_r($row);
 }
}
?>

The above example will output something similar to: 

Array
(
 [Field] => id
 [Type] => int(7)
 [Null] => 
 [Key] => PRI
 [Default] =>
 [Extra] => auto_increment
)
Array
(
 [Field] => email
 [Type] => varchar(100)
 [Null] =>
 [Key] =>
 [Default] =>
 [Extra] =>
)

Notes

Note

For backward compatibility, the following deprecated alias may be used: mysql_listfields

See Also

mysql_field_flags
mysql_info
mysql_list_processes

Description

resource mysql_list_processes(resource link_identifier= =NULL);

Retrieves the current MariaDB server threads.

Parameters

link_identifier

The MariaDB connection. If the link identifier is not specified, the last link opened by mysql_connect is assumed. If no such link is found, it will try to create one as if mysql_connect was called with no arguments. If no connection is found or established, an E_WARNING level error is generated.

Return Values

A result pointer resource on success or FALSE on failure.

Examples

Example 20.55. mysql_list_processes example 

<?php
$link = mysql_connect('localhost', 'mysql_user', 'mysql_password');
$result = mysql_list_processes($link);
while ($row = mysql_fetch_assoc($result)){
 printf('%s %s %s %s %s\n', $row['Id'], $row['Host'], $row['db'],
 $row['Command'], $row['Time']);
}
mysql_free_result($result);
?>

The above example will output something similar to: 

1 localhost test Processlist 0
4 localhost mysql sleep 5

See Also

mysql_thread_id
mysql_stat
mysql_list_tables

Description

resource mysql_list_tables(string database,
resource link_identifier= =NULL);

Retrieves a list of table names from a MariaDB database.

This function is deprecated. It is preferable to use mysql_query to issue an SQL SHOW TABLES [FROM db_name] [LIKE 'pattern'] statement instead.

Parameters

database

The name of the database

link_identifier

The MariaDB connection. If the link identifier is not specified, the last link opened by mysql_connect is assumed. If no such link is found, it will try to create one as if mysql_connect was called with no arguments. If no connection is found or established, an E_WARNING level error is generated.

Return Values

A result pointer resource on success or FALSE on failure.

Use the mysql_tablename function to traverse this result pointer, or any function for result tables, such as mysql_fetch_array.

Changelog

Version Description
4.3.7 This function became deprecated.

Examples

Example 20.56. mysql_list_tables alternative example 

<?php
$dbname = 'mysql_dbname';
if (!mysql_connect('mysql_host', 'mysql_user', 'mysql_password')) {
 echo 'Could not connect to mysql';
 exit;
}
$sql = 'SHOW TABLES FROM $dbname';
$result = mysql_query($sql);
if (!$result) {
 echo 'DB Error, could not list tables\n';
 echo 'MySQL Error: ' . mysql_error();
 exit;
}
while ($row = mysql_fetch_row($result)) {
 echo 'Table: {$row[0]}\n';
}
mysql_free_result($result);
?>

Notes

Note

For backward compatibility, the following deprecated alias may be used: mysql_listtables

See Also

mysql_list_dbs
mysql_tablename
mysql_num_fields

Description

int mysql_num_fields(resource result);

Retrieves the number of fields from a query.

Parameters

result

The result resource that is being evaluated. This result comes from a call to mysql_query.

Return Values

Returns the number of fields in the result set resource on success or FALSE on failure.

Examples

Example 20.57. A mysql_num_fields example 

<?php
$result = mysql_query('SELECT id,email FROM people WHERE id = '42'');
if (!$result) {
 echo 'Could not run query: ' . mysql_error();
 exit;
}
/* returns 2 because id,email === two fields */
echo mysql_num_fields($result);
?>

Notes

Note

For backward compatibility, the following deprecated alias may be used: mysql_numfields

See Also

mysql_select_db
mysql_query
mysql_fetch_field
mysql_num_rows
mysql_num_rows

Description

int mysql_num_rows(resource result);

Retrieves the number of rows from a result set. This command is only valid for statements like SELECT or SHOW that return an actual result set. To retrieve the number of rows affected by a INSERT, UPDATE, REPLACE or DELETE query, use mysql_affected_rows.

Parameters

result

The result resource that is being evaluated. This result comes from a call to mysql_query.

Return Values

The number of rows in a result set on success or FALSE on failure.

Examples

Example 20.58. mysql_num_rows example 

<?php
$link = mysql_connect('localhost', 'mysql_user', 'mysql_password');
mysql_select_db('database', $link);
$result = mysql_query('SELECT * FROM table1', $link);
$num_rows = mysql_num_rows($result);
echo '$num_rows Rows\n';
?>

Notes

Note

If you use mysql_unbuffered_query, mysql_num_rows will not return the correct value until all the rows in the result set have been retrieved.Note

For backward compatibility, the following deprecated alias may be used: mysql_numrows

See Also

mysql_affected_rows
mysql_connect
mysql_data_seek
mysql_select_db
mysql_query
mysql_pconnect

Description

resource mysql_pconnect(string server= =ini_get('mysql.default_host'),
string username= =ini_get('mysql.default_user'),
string password= =ini_get('mysql.default_password'),
int client_flags= =0);

Establishes a persistent connection to a MariaDB server.

mysql-pconnect acts very much like mysql_connect with two major differences.

First, when connecting, the function would first try to find a (persistent) link that's already open with the same host, username and password. If one is found, an identifier for it will be returned instead of opening a new connection.

Second, the connection to the SQL server will not be closed when the execution of the script ends. Instead, the link will remain open for future use (mysql_close will not close links established by mysql_pconnect).

This type of link is therefore called 'persistent'.

Parameters

server

The MariaDB server. It can also include a port number. e.g. 'hostname:port' or a path to a local socket e.g. ':/path/to/socket' for the localhost.

If the PHP directive mysql.default_host is undefined (default), then the default value is 'localhost:3306'

username

The username. Default value is the name of the user that owns the server process.

password

The password. Default value is an empty password.

client_flags

The client_flags parameter can be a combination of the following constants: 128 (enable LOAD DATA LOCAL handling), MYSQL_CLIENT_SSL , MYSQL_CLIENT_COMPRESS , MYSQL_CLIENT_IGNORE_SPACE or MYSQL_CLIENT_INTERACTIVE .

Return Values

Returns a MariaDB persistent link identifier on success, or FALSE on failure.

Changelog

Version Description
4.3.0 Added the client_flags parameter.

Notes

Note

Note, that these kind of links only work if you are using a module version of PHP. See the Persistent Database Connections section for more information.Warning

Using persistent connections can require a bit of tuning of your Apache and MariaDB configurations to ensure that you do not exceed the number of connections allowed by MySQL.Note

You can suppress the error message on failure by prepending a @ to the function name.

See Also

mysql_connect
Persistent Database Connections
mysql_ping

Description

bool mysql_ping(resource link_identifier= =NULL);

Checks whether or not the connection to the server is working. If it has gone down, an automatic reconnection is attempted. This function can be used by scripts that remain idle for a long while, to check whether or not the server has closed the connection and reconnect if necessary.Note

Automatic reconnection is disabled by default in versions of MariaDB >= 5.0.3.

Parameters

link_identifier

The MariaDB connection. If the link identifier is not specified, the last link opened by mysql_connect is assumed. If no such link is found, it will try to create one as if mysql_connect was called with no arguments. If no connection is found or established, an E_WARNING level error is generated.

Return Values

Returns TRUE if the connection to the server MariaDB server is working, otherwise FALSE .

Examples

Example 20.59. A mysql_ping example 

<?php set_time_limit(0);
$conn = mysql_connect('localhost', 'mysqluser', 'mypass');
$db = mysql_select_db('mydb');
/* Assuming this query will take a long time */
$result = mysql_query($sql);
if (!$result) {
 echo 'Query #1 failed, exiting.';
 exit;
}
/* Make sure the connection is still alive, if not, try to reconnect */
if (!mysql_ping($conn)) {
 echo 'Lost connection, exiting after query #1';
 exit;
}
mysql_free_result($result);
/* So the connection is still alive, let's run another query */
$result2 = mysql_query($sql2);
?>

See Also

mysql_thread_id
mysql_list_processes
mysql_query

Description

resource mysql_query(string query,
resource link_identifier= =NULL);

mysql_query sends a unique query (multiple queries are not supported) to the currently active database on the server that's associated with the specified link_identifier.

Parameters

query

An SQL query

The query string should not end with a semicolon. Data inside the query should be properly escaped.

link_identifier

The MariaDB connection. If the link identifier is not specified, the last link opened by mysql_connect is assumed. If no such link is found, it will try to create one as if mysql_connect was called with no arguments. If no connection is found or established, an E_WARNING level error is generated.

Return Values

For SELECT, SHOW, DESCRIBE, EXPLAIN and other statements returning resultset, mysql_query returns a resource on success, or FALSE on error.

For other type of SQL statements, INSERT, UPDATE, DELETE, DROP, etc, mysql_query returns TRUE on success or FALSE on error.

The returned result resource should be passed to mysql_fetch_array, and other functions for dealing with result tables, to access the returned data.

Use mysql_num_rows to find out how many rows were returned for a SELECT statement or mysql_affected_rows to find out how many rows were affected by a DELETE, INSERT, REPLACE, or UPDATE statement.

mysql_query will also fail and return FALSE if the user does not have permission to access the table(s) referenced by the query.

Examples

Example 20.60. Invalid Query

The following query is syntactically invalid, so mysql_query fails and returns FALSE . 

<?php
$result = mysql_query('SELECT * WHERE 1=1');
if (!$result) {
 die('Invalid query: ' . mysql_error());
}
?>

Example 20.61. Valid Query

The following query is valid, so mysql_query returns a resource. 

<?php
// This could be supplied by a user, for example
$firstname = 'fred';
$lastname = 'fox';
// Formulate Query
// This is the best way to perform an SQL query
// For more examples, see mysql_real_escape_string()
$query = sprintf('SELECT firstname, lastname, address, age FROM friends 
 WHERE firstname="%s" AND lastname="%s"',
 mysql_real_escape_string($firstname),
 mysql_real_escape_string($lastname));
// Perform Query
$result = mysql_query($query);
// Check result
// This shows the actual query sent to MySQL, and the error. Useful for debugging.
if (!$result) {
 $message = 'Invalid query: ' . mysql_error() . '\n';
 $message .= 'Whole query: ' . $query;
 die($message);
}
// Use result
// Attempting to print $result won't allow access to information in the resource
// One of the mysql result functions must be used
// See also mysql_result(), mysql_fetch_array(), mysql_fetch_row(), etc.
while ($row = mysql_fetch_assoc($result)) {
 echo $row['firstname'];
 echo $row['lastname'];
 echo $row['address'];
 echo $row['age'];
}
// Free the resources associated with the result set
// This is done automatically at the end of the script mysql_free_result($result);
?>

See Also

mysql_connect
mysql_error
mysql_real_escape_string
mysql_result
mysql_fetch_assoc
mysql_unbuffered_query
mysql_real_escape_string

Description

string mysql_real_escape_string(string unescaped_string,
resource link_identifier= =NULL);

Escapes special characters in the unescaped_string, taking into account the current character set of the connection so that it is safe to place it in a mysql_query. If binary data is to be inserted, this function must be used.

mysql_real_escape_string calls MySQL's library function mysql_real_escape_string, which prepends backslashes to the following characters: \x00, \n, \r, \, ', ' and \x1a.

This function must always (with few exceptions) be used to make data safe before sending a query to MariaDB.

Parameters

unescaped_string

The string that is to be escaped.

link_identifier

The MariaDB connection. If the link identifier is not specified, the last link opened by mysql_connect is assumed. If no such link is found, it will try to create one as if mysql_connect was called with no arguments. If no connection is found or established, an E_WARNING level error is generated.

Return Values

Returns the escaped string, or FALSE on error.

Examples

Example 20.62. Simple mysql_real_escape_string example 

<?php
// Connect
$link = mysql_connect('mysql_host', 'mysql_user', 'mysql_password')
 OR die(mysql_error());
// Query
$query = sprintf('SELECT * FROM users WHERE user="%s" AND password="%s"',
 mysql_real_escape_string($user),
 mysql_real_escape_string($password));
?>

Example 20.63. An example SQL Injection Attack

<?php
// We didn't check $_POST['password'], it could be anything the user wanted! For example:
$_POST['username'] = 'aidan';
$_POST['password'] = '' OR ''='';
// Query database to check if there are any matching users
$query = 'SELECT * FROM users WHERE user="{$_POST["username']}' AND password="{$_POST["password']}'';
mysql_query($query);
// This means the query sent to MariaDB would be:
echo $query;
?>

The query sent to MySQL: 

SELECT * FROM users WHERE user="aidan" AND password="" OR ''=''

This would allow anyone to log in without a valid password.

Notes

Note

A MariaDB connection is required before using mysql_real_escape_string otherwise an error of level E_WARNING is generated, and FALSE is returned. If link_identifier isn't defined, the last MariaDB connection is used.Note

If magic_quotes_gpc is enabled, first apply stripslashes to the data. Using this function on data which has already been escaped will escape the data twice.Note

If this function is not used to escape data, the query is vulnerable to SQL Injection Attacks.Note

mysql_real_escape_string does not escape % and _. These are wildcards in MariaDB if combined with LIKE, GRANT, or REVOKE.

See Also

mysql_client_encoding
addslashes
stripslashes
The magic_quotes_gpc directive
The magic_quotes_runtime directive
mysql_result

Description

string mysql_result(resource result,
int row,
mixed field= =0);

Retrieves the contents of one cell from a MariaDB result set.

When working on large result sets, you should consider using one of the functions that fetch an entire row (specified below). As these functions return the contents of multiple cells in one function call, they're MUCH quicker than mysql_result. Also, note that specifying a numeric offset for the field argument is much quicker than specifying a fieldname or tablename.fieldname argument.

Parameters

result

The result resource that is being evaluated. This result comes from a call to mysql_query.

row

The row number from the result that's being retrieved. Row numbers start at 0.

field

The name or offset of the field being retrieved.

It can be the field's offset, the field's name, or the field's table dot field name (tablename.fieldname). If the column name has been aliased ('select foo as bar from...'), use the alias instead of the column name. If undefined, the first field is retrieved.

Return Values

The contents of one cell from a MariaDB result set on success, or FALSE on failure.

Examples

Example 20.64. mysql_result example 

<?php
$link = mysql_connect('localhost', 'mysql_user', 'mysql_password');
if (!$link) {
 die('Could not connect: ' . mysql_error());
}
if (!mysql_select_db('database_name')) {
 die('Could not select database: ' . mysql_error());
}
$result = mysql_query('SELECT name FROM work.employee');
if (!$result) {
 die('Could not query:' . mysql_error());
}
echo mysql_result($result, 2); // outputs third employee's name mysql_close($link);
?>

Notes

Note

Calls to mysql_result should not be mixed with calls to other functions that deal with the result set.

See Also

mysql_fetch_row
mysql_fetch_array
mysql_fetch_assoc
mysql_fetch_object
mysql_select_db

Description

bool mysql_select_db(string database_name,
resource link_identifier= =NULL);

Sets the current active database on the server that's associated with the specified link identifier. Every subsequent call to mysql_query will be made on the active database.

Parameters

database_name

The name of the database that is to be selected.

link_identifier

The MariaDB connection. If the link identifier is not specified, the last link opened by mysql_connect is assumed. If no such link is found, it will try to create one as if mysql_connect was called with no arguments. If no connection is found or established, an E_WARNING level error is generated.

Return Values

Returns TRUE on success or FALSE on failure.

Examples

Example 20.65. mysql_select_db example 

<?php
$link = mysql_connect('localhost', 'mysql_user', 'mysql_password');
if (!$link) {
 die('Not connected : ' . mysql_error());
}
// make foo the current db
$db_selected = mysql_select_db('foo', $link);
if (!$db_selected) {
 die ('Can\'t use foo : ' . mysql_error());
}
?>

Notes

Note

For backward compatibility, the following deprecated alias may be used: mysql_selectdb

See Also

mysql_connect
mysql_pconnect
mysql_query
mysql_set_charset

Description

bool mysql_set_charset(string charset,
resource link_identifier= =NULL);

Sets the default character set for the current connection.

Parameters

charset

A valid character set name.

link_identifier

The MariaDB connection. If the link identifier is not specified, the last link opened by mysql_connect is assumed. If no such link is found, it will try to create one as if mysql_connect was called with no arguments. If no connection is found or established, an E_WARNING level error is generated.

Return Values

Returns TRUE on success or FALSE on failure.

Notes

Note

This function requires MariaDB 5.0.7 or later.Note

This is the preferred way to change the charset. Using mysql_query to execute SET NAMES .. is not recommended.

See Also

mysql_client_encoding
List of character sets that MariaDB supports
mysql_stat

Description

string mysql_stat(resource link_identifier= =NULL);

mysql_stat returns the current server status.

Parameters

link_identifier

The MariaDB connection. If the link identifier is not specified, the last link opened by mysql_connect is assumed. If no such link is found, it will try to create one as if mysql_connect was called with no arguments. If no connection is found or established, an E_WARNING level error is generated.

Return Values

Returns a string with the status for uptime, threads, queries, open tables, flush tables and queries per second. For a complete list of other status variables, you have to use the SHOW STATUS SQL command. If link_identifier is invalid, NULL is returned.

Examples

Example 20.66. mysql_stat example 

<?php
$link = mysql_connect('localhost', 'mysql_user', 'mysql_password');
$status = explode(' ', mysql_stat($link));
print_r($status);
?>

The above example will output something similar to: 

Array
(
 [0] => Uptime: 5380
 [1] => Threads: 2
 [2] => Questions: 1321299
 [3] => Slow queries: 0
 [4] => Opens: 26
 [5] => Flush tables: 1
 [6] => Open tables: 17
 [7] => Queries per second avg: 245.595
)

Example 20.67. Alternative mysql_stat example 

<?php
$link = mysql_connect('localhost', 'mysql_user', 'mysql_password');
$result = mysql_query('SHOW STATUS', $link);
while ($row = mysql_fetch_assoc($result)) {
 echo $row['Variable_name'] . ' = ' . $row['Value'] . '\n';
}
?>

The above example will output something similar to: 

back_log = 50
basedir = /usr/local/
bdb_cache_size = 8388600
bdb_log_buffer_size = 32768
bdb_home = /var/db/mysql/
bdb_max_lock = 10000
bdb_logdir =
bdb_shared_data = OFF bdb_tmpdir = /var/tmp/
...

See Also

mysql_get_server_info
mysql_list_processes
mysql_tablename

Description

string mysql_tablename(resource result,
int i);

Retrieves the table name from a result.

This function is deprecated. It is preferable to use mysql_query to issue an SQL SHOW TABLES [FROM db_name] [LIKE 'pattern'] statement instead.

Parameters

result

A result pointer resource that's returned from mysql_list_tables.

i

The integer index (row/table number)

Return Values

The name of the table on success or FALSE on failure.

Use the mysql_tablename function to traverse this result pointer, or any function for result tables, such as mysql_fetch_array.

Examples

Example 20.68. mysql_tablename example 

<?php mysql_connect('localhost', 'mysql_user', 'mysql_password');
$result = mysql_list_tables('mydb');
$num_rows = mysql_num_rows($result);
for ($i = 0; $i < $num_rows; $i++) {
 echo 'Table: ', mysql_tablename($result, $i), '\n';
}
mysql_free_result($result);
?>

Notes

Note

The mysql_num_rows function may be used to determine the number of tables in the result pointer.

See Also

mysql_list_tables
mysql_field_table
mysql_db_name
mysql_thread_id

Description

int mysql_thread_id(resource link_identifier= =NULL);

Retrieves the current thread ID. If the connection is lost, and a reconnect with mysql_ping is executed, the thread ID will change. This means only retrieve the thread ID when needed.

Parameters

link_identifier

The MariaDB connection. If the link identifier is not specified, the last link opened by mysql_connect is assumed. If no such link is found, it will try to create one as if mysql_connect was called with no arguments. If no connection is found or established, an E_WARNING level error is generated.

Return Values

The thread ID on success or FALSE on failure.

Examples

Example 20.69. mysql_thread_id example 

<?php
$link = mysql_connect('localhost', 'mysql_user', 'mysql_password');
$thread_id = mysql_thread_id($link);
if ($thread_id){
 printf('current thread id is %d\n', $thread_id);
}
?>

The above example will output something similar to: 

current thread id is 73

See Also

mysql_ping
mysql_list_processes
mysql_unbuffered_query

Description

resource mysql_unbuffered_query(string query,
resource link_identifier= =NULL);

mysql_unbuffered_query sends the SQL query query to MariaDB without automatically fetching and buffering the result rows as mysql_query does. This saves a considerable amount of memory with SQL queries that produce large result sets, and you can start working on the result set immediately after the first row has been retrieved as you don't have to wait until the complete SQL query has been performed. To use mysql_unbuffered_query while multiple database connections are open, you must specify the optional parameter link_identifier to identify which connection you want to use.

Parameters

query

The SQL query to execute.

Data inside the query should be properly escaped.

link_identifier

The MariaDB connection. If the link identifier is not specified, the last link opened by mysql_connect is assumed. If no such link is found, it will try to create one as if mysql_connect was called with no arguments. If no connection is found or established, an E_WARNING level error is generated.

Return Values

For SELECT, SHOW, DESCRIBE or EXPLAIN statements, mysql_unbuffered_query returns a resource on success, or FALSE on error.

For other type of SQL statements, UPDATE, DELETE, DROP, etc, mysql_unbuffered_query returns TRUE on success or FALSE on error.

Notes

Note

The benefits of mysql_unbuffered_query come at a cost: you cannot use mysql_num_rows and mysql_data_seek on a result set returned from mysql_unbuffered_query, until all rows are fetched. You also have to fetch all result rows from an unbuffered SQL query before you can send a new SQL query to MySQL, using the same link_identifier.

See Also

mysql_query

MySQL Improved Extension (Mysqli)

Examples
Overview
Quick start guide
Installing/Configuring
The mysqli Extension and Persistent Connections
Predefined Constants
Notes
The MySQLi Extension Function Summary
The mysqli class (mysqli)
The mysqli_stmt class (mysqli_stmt)
The mysqli_result class (mysqli_result)
The mysqli_driver class (mysqli_driver)
The mysqli_warning class (mysqli_warning)
The mysqli_sql_exception class (mysqli_sql_exception)
Aliases and deprecated Mysqli Functions

The mysqli extension allows you to access the functionality provided by MariaDB and above. More information about the MariaDB Database server can be found at http://www.mysql.com/

An overview of software available for using MariaDB from PHP can be found at , "Overview"

Documentation for MariaDB can be found at http://dev.mysql.com/doc/.

Parts of this documentation included from MariaDB manual with permissions of Oracle Corporation.

Examples

All examples in the mysqli documentation use the world database. The world database can be found at http://downloads.mysql.com/docs/world.sql.gz

Overview

This section provides an introduction to the options available to you when developing a PHP application that needs to interact with a MariaDB database.

What is an API?

An Application Programming Interface, or API, defines the classes, methods, functions and variables that your application will need to call in order to carry out its desired task. In the case of PHP applications that need to communicate with databases the necessary APIs are usually exposed via PHP extensions.

APIs can be procedural or object-oriented. With a procedural API you call functions to carry out tasks, with the object-oriented API you instantiate classes and then call methods on the resulting objects. Of the two the latter is usually the preferred interface, as it is more modern and leads to better organised code.

When writing PHP applications that need to connect to the MariaDB server there are several API options available. This document discusses what is available and how to select the best solution for your application.

What is a Connector?

In the MariaDB documentation, the term connector refers to a piece of software that allows your application to connect to the MariaDB database server. MariaDB provides connectors for a variety of languages, including PHP.

If your PHP application needs to communicate with a database server you will need to write PHP code to perform such activities as connecting to the database server, querying the database and other database-related functions. Software is required to provide the API that your PHP application will use, and also handle the communication between your application and the database server, possibly using other intermediate libraries where necessary. This software is known generically as a connector, as it allows your application to connect to a database server.

What is a Driver?

A driver is a piece of software designed to communicate with a specific type of database server. The driver may also call a library, such as the MariaDB Client Library or the MariaDB Native Driver. These libraries implement the low-level protocol used to communicate with the MariaDB database server.

By way of an example, the PHP Data Objects (PDO) database abstraction layer may use one of several database-specific drivers. One of the drivers it has available is the PDO MYSQL driver, which allows it to interface with the MariaDB server.

Sometimes people use the terms connector and driver interchangeably, this can be confusing. In the MySQL-related documentation the term "driver" is reserved for software that provides the database-specific part of a connector package.

What is an Extension?

In the PHP documentation you will come across another term - extension. The PHP code consists of a core, with optional extensions to the core functionality. PHP's MySQL-related extensions, such as the mysqli extension, and the MariaDB extension, are implemented using the PHP extension framework.

An extension typically exposes an API to the PHP programmer, to allow its facilities to be used programmatically. However, some extensions which use the PHP extension framework do not expose an API to the PHP programmer.

The PDO MariaDB driver extension, for example, does not expose an API to the PHP programmer, but provides an interface to the PDO layer above it.

The terms API and extension should not be taken to mean the same thing, as an extension may not necessarily expose an API to the programmer.

What are the main PHP API offerings for using MySQL?

There are three main API options when considering connecting to a MariaDB database server:

Each has its own advantages and disadvantages. The following discussion aims to give a brief introduction to the key aspects of each API.

What is PHP's MariaDB Extension?

This is the original extension designed to allow you to develop PHP applications that interact with a MariaDB database. The MariaDB extension provides a procedural interface and is intended for use only with MariaDB versions older than 4.1.3. This extension can be used with versions of MariaDB 4.1.3 or newer, but not all of the latest MariaDB server features will be available.Note

If you are using MariaDB versions 4.1.3 or later it is strongly recommended that you use the mysqli extension instead.

The MariaDB extension source code is located in the PHP extension directory ext/mysql.

For further information on the MariaDB extension, see , "Original MariaDB API (MariaDB)".

What is PHP's mysqli Extension?

The mysqli extension, or as it is sometimes known, the MariaDB improved extension, was developed to take advantage of new features found in MariaDB systems versions 4.1.3 and newer. The mysqli extension is included with PHP versions 5 and later.

The mysqli extension has a number of benefits, the key enhancements over the MariaDB extension being:

Note

If you are using MariaDB versions 4.1.3 or later it is strongly recommended that you use this extension.

As well as the object-oriented interface the extension also provides a procedural interface.

The mysqli extension is built using the PHP extension framework, its source code is located in the directory ext/mysqli.

For further information on the mysqli extension, see , "MySQL Improved Extension (Mysqli)".

What is PDO?

PHP Data Objects, or PDO, is a database abstraction layer specifically for PHP applications. PDO provides a consistent API for your PHP application regardless of the type of database server your application will connect to. In theory, if you are using the PDO API, you could switch the database server you used, from say Firebird to MySQL, and only need to make minor changes to your PHP code.

Other examples of database abstraction layers include JDBC for Java applications and DBI for Perl.

While PDO has its advantages, such as a clean, simple, portable API, its main disadvantage is that it doesn't allow you to use all of the advanced features that are available in the latest versions of MariaDB server. For example, PDO does not allow you to use MySQL's support for Multiple Statements.

PDO is implemented using the PHP extension framework, its source code is located in the directory ext/pdo.

For further information on PDO, see the http://www.php.net/book.pdo.

What is the PDO MYSQL driver?

The PDO MYSQL driver is not an API as such, at least from the PHP programmer's perspective. In fact the PDO MYSQL driver sits in the layer below PDO itself and provides MySQL-specific functionality. The programmer still calls the PDO API, but PDO uses the PDO MYSQL driver to carry out communication with the MariaDB server.

The PDO MYSQL driver is one of several available PDO drivers. Other PDO drivers available include those for the Firebird and PostgreSQL database servers.

The PDO MYSQL driver is implemented using the PHP extension framework. Its source code is located in the directory ext/pdo_mysql. It does not expose an API to the PHP programmer.

For further information on the PDO MYSQL driver, see , "MySQL Functions (PDO_MYSQL) (MySQL (PDO))".

What is PHP's MariaDB Native Driver?

In order to communicate with the MariaDB database server the MariaDB extension, mysqli and the PDO MYSQL driver each use a low-level library that implements the required protocol. In the past, the only available library was the MariaDB Client Library, otherwise known as libmysql.

However, the interface presented by libmysql was not optimized for communication with PHP applications, as libmysql was originally designed with C applications in mind. For this reason the MariaDB Native Driver, mysqlnd, was developed as an alternative to libmysql for PHP applications.

The MariaDB extension, the mysqli extension and the PDO MariaDB driver can each be individually configured to use either libmysql or mysqlnd. As mysqlnd is designed specifically to be utilised in the PHP system it has numerous memory and speed enhancements over libmysql. You are strongly encouraged to take advantage of these improvements.Note

The MariaDB Native Driver can only be used with MariaDB server versions 4.1.3 and later.

The MariaDB Native Driver is implemented using the PHP extension framework. The source code is located in ext/mysqlnd. It does not expose an API to the PHP programmer.

Comparison of Features

The following table compares the functionality of the three main methods of connecting to MariaDB from PHP:

PHP's mysqli Extension PDO (Using PDO MariaDB Driver and MariaDB Native Driver) PHP's MariaDB Extension
PHP version introduced 5.0 5.0 Prior to 3.0
Included with PHP 5.x yes yes Yes
MySQL development status Active development Active development as of PHP 5.3 Maintenance only
Recommended by MariaDB for new projects Yes - preferred option Yes No
API supports Charsets Yes Yes No
API supports server-side Prepared Statements Yes Yes No
API supports client-side Prepared Statements No Yes No
API supports Stored Procedures Yes Yes No
API supports Multiple Statements Yes Most No
Supports all MariaDB 4.1+ functionality Yes Most No

Quick start guide

Dual procedural and object-oriented interface
Connections
Executing statements
Prepared Statements
Stored Procedures
Multiple Statements
API support for transactions
Metadata

This quick start guide will help with choosing and gaining familiarity with the PHP MariaDB API.

This quick start gives an overview on the mysqli extension. Code examples are provided for all major aspects of the API. Database concepts are explained to the degree needed for presenting concepts specific to MariaDB.

Required: A familiarity with the PHP programming language, the SQL language, and basic knowledge of the MariaDB server.

Dual procedural and object-oriented interface

The mysqli extension features a dual interface. It supports the procedural and object-oriented programming paradigm.

Users migrating from the old mysql extension may prefer the procedural interface. The procedural interface is similar to that of the old mysql extension. In many cases, the function names differ only by prefix. Some mysqli functions take a connection handle as their first argument, whereas matching functions in the old mysql interface take it as an optional last argument.

Example 20.70. Easy migration from the old mysql extension

<?php
$mysqli = mysqli_connect('example.com', 'user', 'password', 'database');
$res = mysqli_query($mysqli, 'SELECT 'Please, do not use ' AS _msg FROM DUAL');
$row = mysqli_fetch_assoc($res);
echo $row['_msg'];
$mysql = mysql_connect('localhost', 'root', '');
mysql_select_db('test');
$res = mysql_query('SELECT 'the mysql extension for new developments.' AS _msg FROM DUAL', $mysql);
$row = mysql_fetch_assoc($res);
echo $row['_msg'];
?>

The above example will output: 

Please, do not use the mysql extension for new developments.

The object-oriented interface

In addition to the classical procedural interface, users can choose to use the object-oriented interface. The documentation is organized using the object-oriented interface. The object-oriented interface shows functions grouped by their purpose, making it easier to get started. The reference section gives examples for both syntax variants.

There are no significant performance differences between the two interfaces. Users can base their choice on personal preference.

Example 20.71. Object-oriented and procedural interface

<?php
$mysqli = mysqli_connect('example.com', 'user', 'password', 'database');
if (mysqli_connect_errno($mysqli)) {
 echo 'Failed to connect to MySQL: ' . mysqli_connect_error();
}
$res = mysqli_query($mysqli, 'SELECT 'A world full of ' AS _msg FROM DUAL');
$row = mysqli_fetch_assoc($res);
echo $row['_msg'];
$mysqli = new mysqli('example.com', 'user', 'password', 'database');
if ($mysqli->connect_errno) {
 echo 'Failed to connect to MySQL: ' . $mysqli->connect_error;
}
$res = $mysqli->query('SELECT 'choices to please everybody,' AS _msg FROM DUAL');
$row = $res->fetch_assoc();
echo $row['_msg'];
?>

The above example will output: 

A world full of choices to please everybody.

The object oriented interface is used for the quickstart because the reference section is organized that way.

Mixing styles

It is possible to switch between styles at any time. Mixing both styles is not recommended for code clarity and coding style reasons.

Example 20.72. Bad coding style

<?php
$mysqli = new mysqli('example.com', 'user', 'password', 'database');
if ($mysqli->connect_errno) {
 echo 'Failed to connect to MySQL: ' . $mysqli->connect_error;
}
$res = mysqli_query($mysqli, 'SELECT 'Possible but bad style.' AS _msg FROM DUAL');
if (!$res) {
 echo 'Failed to run query: (' . $mysqli->errno . ') ' . $mysqli->error;
}
if ($row = $res->fetch_assoc()) {
 echo $row['_msg'];
}
?>

The above example will output: 

Possible but bad style.

See also

mysqli::__construct
mysqli::query
mysqli_result::fetch_assoc
$mysqli::connect_errno
$mysqli::connect_error
$mysqli::errno
$mysqli::error
The MySQLi Extension Function Summary
Connections

The MariaDB server supports the use of different transport layers for connections. Connections use TCP/IP, Unix domain sockets or Windows named pipes.

The hostname localhost has a special meaning. It is bound to the use of Unix domain sockets. It is not possible to open a TCP/IP connection using the hostname localhost you must use 127.0.0.1 instead.

Example 20.73. Special meaning of localhost

<?php
$mysqli = new mysqli('localhost', 'user', 'password', 'database');
if ($mysqli->connect_errno) {
 echo 'Failed to connect to MySQL: (' . $mysqli->connect_errno . ') ' . $mysqli->connect_error;
}
echo $mysqli->host_info . '\n';
$mysqli = new mysqli('127.0.0.1', 'user', 'password', 'database', 3306);
if ($mysqli->connect_errno) {
 echo 'Failed to connect to MySQL: (' . $mysqli->connect_errno . ') ' . $mysqli->connect_error;
}
echo $mysqli->host_info . '\n';
?>

The above example will output: 

Localhost via UNIX socket
127.0.0.1 via TCP/IP

Connection parameter defaults

Depending on the connection function used, assorted parameters can be omitted. If a parameter is not provided, then the extension attempts to use the default values that are set in the PHP configuration file.

Example 20.74. Setting defaults

mysqli.default_host=192.168.2.27
mysqli.default_user=root mysqli.default_pw=''
mysqli.default_port=3306
mysqli.default_socket=/tmp/mysql.sock

The resulting parameter values are then passed to the client library that is used by the extension. If the client library detects empty or unset parameters, then it may default to the library built-in values.

Built-in connection library defaults

If the host value is unset or empty, then the client library will default to a Unix socket connection on localhost. If socket is unset or empty, and a Unix socket connection is requested, then a connection to the default socket on /tmp/mysql.sock is attempted.

On Windows systems, the host name . is interpreted by the client library as an attempt to open a Windows named pipe based connection. In this case the socket parameter is interpreted as the pipe name. If not given or empty, then the socket (pipe name) defaults to \\.\pipe\MySQL.

If neither a Unix domain socket based not a Windows named pipe based connection is to be be established and the port parameter value is unset, the library will default to port 3306.

The mysqlnd library and the MariaDB Client Library (libmysql) implement the same logic for determining defaults.

Connection options

Connection options are available to, for example, set init commands which are executed upon connect, or for requesting use of a certain charset. Connection options must be set before a network connection is established.

For setting a connection option, the connect operation has to be performed in three steps: creating a connection handle with mysqli_init, setting the requested options using mysqli_options, and establishing the network connection with mysqli_real_connect.

Connection pooling

The mysqli extension supports persistent database connections, which are a special kind of pooled connections. By default, every database connection opened by a script is either explicitly closed by the user during runtime or released automatically at the end of the script. A persistent connection is not. Instead it is put into a pool for later reuse, if a connection to the same server using the same username, password, socket, port and default database is opened. Reuse saves connection overhead.

Every PHP process is using its own mysqli connection pool. Depending on the web server deployment model, a PHP process may serve one or multiple requests. Therefore, a pooled connection may be used by one or more scripts subsequently.

Persistent connection

If a unused persistent connection for a given combination of host, username, password, socket, port and default database can not be found in the connection pool, then mysqli opens a new connection. The use of persistent connections can be enabled and disabled using the PHP directive mysqli.allow_persistent. The total number of connections opened by a script can be limited with mysqli.max_links. The maximum number of persistent connections per PHP process can be restricted with mysqli.max_persistent. Please note, that the web server may spawn many PHP processes.

A common complain about persistent connections is that their state is not reset before reuse. For example, open and unfinished transactions are not automatically rolled back. But also, authorization changes which happened in the time between putting the connection into the pool and reusing it are not reflected. This may be seen as an unwanted side-effect. On the contrary, the name persistent may be understood as a promise that the state is persisted.

The mysqli extension supports both interpretations of a persistent connection: state persisted, and state reset before reuse. The default is reset. Before a persistent connection is reused, the mysqli extension implicitly calls mysqli_change_user to reset the state. The persistent connection appears to the user as if it was just opened. No artifacts from previous usages are visible.

The mysqli_change_user function is an expensive operation. For best performance, users may want to recompile the extension with the compile flag MYSQLI_NO_CHANGE_USER_ON_PCONNECT being set.

It is left to the user to choose between safe behavior and best performance. Both are valid optimization goals. For ease of use, the safe behavior has been made the default at the expense of maximum performance.

See also

mysqli::__construct
mysqli::init
mysqli::options
mysqli::real_connect
mysqli::change_user
$mysqli::host_info
MySQLi Configuration Options
Persistent Database Connections
Executing statements

Statements can be executed with the mysqli-query, mysqli_real_query and mysqli_multi_query functions. The mysqli_query function is the most common, and combines the executing statement with a buffered fetch of its result set, if any, in one call. Calling mysqli_query is identical to calling mysqli_real_query followed by mysqli_store_result.

The mysqli_multi_query function is used with multiple statements.

Example 20.75. Bad coding style

<?php
$mysqli = new mysqli('example.com', 'user', 'password', 'database');
if ($mysqli->connect_errno) {
 echo 'Failed to connect to MySQL: (' . $mysqli->connect_errno . ') ' . $mysqli->connect_error;
}
if (!$mysqli->query('DROP TABLE IF EXISTS test') ||
 !$mysqli->query('CREATE TABLE test(id INT)') ||
 !$mysqli->query('INSERT INTO test(id) VALUES (1)')) {
 echo 'Table creation failed: (' . $mysqli->errno . ') ' . $mysqli->error;
}
?>

Buffered result sets

After statement execution results can be retrieved at once to be buffered by the client or by read row by row. Client-side result set buffering allows the server to free resources associated with the statement results as early as possible. Generally speaking, clients are slow consuming result sets. Therefore, it is recommended to use buffered result sets. mysqli_query combines statement execution and result set buffering.

PHP applications can navigate freely through buffered results. Navigation is fast because the result sets are held in client memory. Please, keep in mind that it is often easier to scale by client than it is to scale the server.

Example 20.76. Navigation through buffered results

<?php
$mysqli = new mysqli('example.com', 'user', 'password', 'database');
if ($mysqli->connect_errno) {
 echo 'Failed to connect to MySQL: (' . $mysqli->connect_errno . ') ' . $mysqli->connect_error;
}
if (!$mysqli->query('DROP TABLE IF EXISTS test') ||
 !$mysqli->query('CREATE TABLE test(id INT)') ||
 !$mysqli->query('INSERT INTO test(id) VALUES (1), (2), (3)')) {
 echo 'Table creation failed: (' . $mysqli->errno . ') ' . $mysqli->error;
}
$res = $mysqli->query('SELECT id FROM test ORDER BY id ASC');
echo 'Reverse order...\n';
for ($row_no = $res->num_rows - 1; $row_no >= 0; $row_no--) {
 $res->data_seek($row_no);
 $row = $res->fetch_assoc();
 echo ' id = ' . $row['id'] . '\n';
}
echo 'Result set order...\n';
$res->data_seek(0);
while ($row = $res->fetch_assoc()) {
 echo ' id = ' . $row['id'] . '\n';
}
?>

The above example will output: 

Reverse order...
 id = 3
 id = 2
 id = 1
Result set order...
 id = 1
 id = 2
 id = 3

Unbuffered result sets

If client memory is a short resource and freeing server resources as early as possible to keep server load low is not needed, unbuffered results can be used. Scrolling through unbuffered results is not possible before all rows have been read.

Example 20.77. Navigation through buffered results

<?php
$mysqli->real_query('SELECT id FROM test ORDER BY id ASC');
$res = $mysqli->use_result();
echo 'Result set order...\n';
while ($row = $res->fetch_assoc()) {
 echo ' id = ' . $row['id'] . '\n';
}
?>

Result set values data types

The mysqli-query, mysqli_real_query and mysqli_multi_query functions are used to execute non-prepared statements. At the level of the MariaDB Client Server Protocol, the command COM_QUERY and the text protocol are used for statement execution. With the text protocol, the MariaDB server converts all data of a result sets into strings before sending. This conversion is done regardless of the SQL result set column data type. The mysql client libraries receive all column values as strings. No further client-side casting is done to convert columns back to their native types. Instead, all values are provided as PHP strings.

Example 20.78. Text protocol returns strings by default

<?php
$mysqli = new mysqli('example.com', 'user', 'password', 'database');
if ($mysqli->connect_errno) {
 echo 'Failed to connect to MySQL: (' . $mysqli->connect_errno . ') ' . $mysqli->connect_error;
}
if (!$mysqli->query('DROP TABLE IF EXISTS test') ||
 !$mysqli->query('CREATE TABLE test(id INT, label CHAR(1))') ||
 !$mysqli->query('INSERT INTO test(id, label) VALUES (1, 'a')')) {
 echo 'Table creation failed: (' . $mysqli->errno . ') ' . $mysqli->error;
}
$res = $mysqli->query('SELECT id, label FROM test WHERE id = 1');
$row = $res->fetch_assoc();
printf('id = %s (%s)\n', $row['id'], gettype($row['id']));
printf('label = %s (%s)\n', $row['label'], gettype($row['label']));
?>

The above example will output: 

id = 1 (string)
label = a (string)

It is possible to convert integer and float columns back to PHP numbers by setting the MYSQLI_OPT_INT_AND_FLOAT_NATIVE connection option, if using the mysqlnd library. If set, the mysqlnd library will check the result set meta data column types and convert numeric SQL columns to PHP numbers, if the PHP data type value range allows for it. This way, for example, SQL INT columns are returned as integers.

Example 20.79. Native data types with mysqlnd and connection option

<?php
$mysqli = mysqli_init();
$mysqli->options(MYSQLI_OPT_INT_AND_FLOAT_NATIVE, 1);
$mysqli->real_connect('example.com', 'user', 'password', 'database');
if ($mysqli->connect_errno) {
 echo 'Failed to connect to MySQL: (' . $mysqli->connect_errno . ') ' . $mysqli->connect_error;
}
if (!$mysqli->query('DROP TABLE IF EXISTS test') ||
 !$mysqli->query('CREATE TABLE test(id INT, label CHAR(1))') ||
 !$mysqli->query('INSERT INTO test(id, label) VALUES (1, 'a')')) {
 echo 'Table creation failed: (' . $mysqli->errno . ') ' . $mysqli->error;
}
$res = $mysqli->query('SELECT id, label FROM test WHERE id = 1');
$row = $res->fetch_assoc();
printf('id = %s (%s)\n', $row['id'], gettype($row['id']));
printf('label = %s (%s)\n', $row['label'], gettype($row['label']));
?>

The above example will output: 

id = 1 (integer)
label = a (string)

See also

mysqli::__construct
mysqli::init
mysqli::options
mysqli::real_connect
mysqli::query
mysqli::multi_query
mysqli::use_result
mysqli::store_result
mysqli_result::free
Prepared Statements

The MariaDB database supports prepared statements. A prepared statement or a parameterized statement is used to execute the same statement repeatedly with high efficiency.

Basic workflow

The prepared statement execution consists of two stages: prepare and execute. At the prepare stage a statement template is send to the database server. The server performs a syntax check and initializes server internal resources for later use.

The MariaDB server supports using anonymous, positional placeholder with ?.

Example 20.80. First stage: prepare

<?php
$mysqli = new mysqli('example.com', 'user', 'password', 'database');
if ($mysqli->connect_errno) {
 echo 'Failed to connect to MySQL: (' . $mysqli->connect_errno . ') ' . $mysqli->connect_error;
}
/* Non-prepared statement */
if (!$mysqli->query('DROP TABLE IF EXISTS test') || !$mysqli->query('CREATE TABLE test(id INT)')) {
 echo 'Table creation failed: (' . $mysqli->errno . ') ' . $mysqli->error;
}
/* Prepared statement, stage 1: prepare */
if (!($stmt = $mysqli->prepare('INSERT INTO test(id) VALUES (?)'))) {
 echo 'Prepare failed: (' . $mysqli->errno . ') ' . $mysqli->error;
}
?>

Prepare is followed by execute. During execute the client binds parameter values and sends them to the server. The server creates a statement from the statement template and the bound values to execute it using the previously created internal resources.

Example 20.81. Second stage: bind and execute

<?php
/* Prepared statement, stage 2: bind and execute */
$id = 1;
if (!$stmt->bind_param('i', $id)) {
 echo 'Binding parameters failed: (' . $stmt->errno . ') ' . $stmt->error;
}
if (!$stmt->execute()) {
 echo 'Execute failed: (' . $stmt->errno . ') ' . $stmt->error;
}
?>

Repeated execution

A prepared statement can be executed repeatedly. Upon every execution the current value of the bound variable is evaluated and send to the server. The statement is not parsed again. The statement template is not transferred to the server again.

Example 20.82. INSERT prepared once, executed multiple times

<?php
$mysqli = new mysqli('example.com', 'user', 'password', 'database');
if ($mysqli->connect_errno) {
 echo 'Failed to connect to MySQL: (' . $mysqli->connect_errno . ') ' . $mysqli->connect_error;
}
/* Non-prepared statement */
if (!$mysqli->query('DROP TABLE IF EXISTS test') || !$mysqli->query('CREATE TABLE test(id INT)')) {
 echo 'Table creation failed: (' . $mysqli->errno . ') ' . $mysqli->error;
}
/* Prepared statement, stage 1: prepare */
if (!($stmt = $mysqli->prepare('INSERT INTO test(id) VALUES (?)'))) {
 echo 'Prepare failed: (' . $mysqli->errno . ') ' . $mysqli->error;
}
/* Prepared statement, stage 2: bind and execute */
$id = 1;
if (!$stmt->bind_param('i', $id)) {
 echo 'Binding parameters failed: (' . $stmt->errno . ') ' . $stmt->error;
}
if (!$stmt->execute()) {
 echo 'Execute failed: (' . $stmt->errno . ') ' . $stmt->error;
}
/* Prepared statement: repeated execution, only data transferred from client to server */
for ($id = 2; $id < 5; $id++) {
 if (!$stmt->execute()) {
 echo 'Execute failed: (' . $stmt->errno . ') ' . $stmt->error;
 }
}
/* explicit close recommended */
$stmt->close();
/* Non-prepared statement */
$res = $mysqli->query('SELECT id FROM test');
var_dump($res->fetch_all());
?>

The above example will output: 

array(4) {
 [0]=>
 array(1) {
 [0]=>
 string(1) '1'
 }
 [1]=>
 array(1) {
 [0]=>
 string(1) '2'
 }
 [2]=>
 array(1) {
 [0]=>
 string(1) '3'
 }
 [3]=>
 array(1) {
 [0]=>
 string(1) '4'
 }
}

Every prepared statement occupies server resources. Statements should be closed explicitly immediately after use. If not done explicitly, the statement will be closed when the statement handle is freed by PHP.

Using a prepared statement is not always the most efficient way of executing a statement. A prepared statement executed only once causes more client-server round-trips than a non-prepared statement. This is why the SELECT is not run as a prepared statement above.

Also, consider the use of the MariaDB multi-INSERT SQL syntax for INSERTs. For the example, multi-INSERT requires less round-trips between the server and client than the prepared statement shown above.

Example 20.83. Less round trips using multi-INSERT SQL

<?php if (!$mysqli->query('INSERT INTO test(id) VALUES (1), (2), (3), (4)')) {
 echo 'Multi-INSERT failed: (' . $mysqli->errno . ') ' . $mysqli->error;
}
?>

Result set values data types

The MariaDB Client Server Protocol defines a different data transfer protocol for prepared statements and non-prepared statements. Prepared statements are using the so called binary protocol. The MariaDB server sends result set data 'as is' in binary format. Results are not serialized into strings before sending. The client libraries do not receive strings only. Instead, they will receive binary data and try to convert the values into appropriate PHP data types. For example, results from an SQL INT column will be provided as PHP integer variables.

Example 20.84. Native datatypes

<?php
$mysqli = new mysqli('example.com', 'user', 'password', 'database');
if ($mysqli->connect_errno) {
 echo 'Failed to connect to MySQL: (' . $mysqli->connect_errno . ') ' . $mysqli->connect_error;
}
if (!$mysqli->query('DROP TABLE IF EXISTS test') ||
 !$mysqli->query('CREATE TABLE test(id INT, label CHAR(1))') ||
 !$mysqli->query('INSERT INTO test(id, label) VALUES (1, 'a')')) {
 echo 'Table creation failed: (' . $mysqli->errno . ') ' . $mysqli->error;
}
$stmt = $mysqli->prepare('SELECT id, label FROM test WHERE id = 1');
$stmt->execute();
$res = $stmt->get_result();
$row = $res->fetch_assoc();
printf('id = %s (%s)\n', $row['id'], gettype($row['id']));
printf('label = %s (%s)\n', $row['label'], gettype($row['label']));
?>

The above example will output: 

id = 1 (integer)
label = a (string)

This behavior differs from non-prepared statements. By default, non-prepared statements return all results as strings. This default can be changed using a connection option. If the connection option is used, there are no differences.

Fetching results using bound variables

Results from prepared statements can either be retrieved by binding output variables, or by requesting a mysqli_result object.

Output variables must be bound after statement execution. One variable must be bound for every column of the statements result set.

Example 20.85. Output variable binding

<?php
$mysqli = new mysqli('example.com', 'user', 'password', 'database');
if ($mysqli->connect_errno) {
 echo 'Failed to connect to MySQL: (' . $mysqli->connect_errno . ') ' . $mysqli->connect_error;
}
if (!$mysqli->query('DROP TABLE IF EXISTS test') ||
 !$mysqli->query('CREATE TABLE test(id INT, label CHAR(1))') ||
 !$mysqli->query('INSERT INTO test(id, label) VALUES (1, 'a')')) {
 echo 'Table creation failed: (' . $mysqli->errno . ') ' . $mysqli->error;
}
if (!($stmt = $mysqli->prepare('SELECT id, label FROM test'))) {
 echo 'Prepare failed: (' . $mysqli->errno . ') ' . $mysqli->error;
}
if (!$stmt->execute()) {
 echo 'Execute failed: (' . $mysqli->errno . ') ' . $mysqli->error;
}
$out_id = NULL;
$out_label = NULL;
if (!$stmt->bind_result($out_id, $out_label)) {
 echo 'Binding output parameters failed: (' . $stmt->errno . ') ' . $stmt->error;
}
while ($stmt->fetch()) {
 printf('id = %s (%s), label = %s (%s)\n', $out_id, gettype($out_id), $out_label, gettype($out_label));
}
?>

The above example will output: 

id = 1 (integer), label = a (string)

Prepared statements return unbuffered result sets by default. The results of the statement are not implicitly fetched and transferred from the server to the client for client-side buffering. The result set takes server resources until all results have been fetched by the client. Thus it is recommended to consume results timely. If a client fails to fetch all results or the client closes the statement before having fetched all data, the data has to be fetched implicitly by mysqli.

It is also possible to buffer the results of a prepared statement using mysqli_stmt_store_result.

Fetching results using mysqli_result interface

Instead of using bound results, results can also be retrieved through the mysqli_result interface. mysqli_stmt_get_result returns a buffered result set.

Example 20.86. Using mysqli_result to fetch results

<?php
$mysqli = new mysqli('example.com', 'user', 'password', 'database');
if ($mysqli->connect_errno) {
 echo 'Failed to connect to MySQL: (' . $mysqli->connect_errno . ') ' . $mysqli->connect_error;
}
if (!$mysqli->query('DROP TABLE IF EXISTS test') ||
 !$mysqli->query('CREATE TABLE test(id INT, label CHAR(1))') ||
 !$mysqli->query('INSERT INTO test(id, label) VALUES (1, 'a')')) {
 echo 'Table creation failed: (' . $mysqli->errno . ') ' . $mysqli->error;
}
if (!($stmt = $mysqli->prepare('SELECT id, label FROM test ORDER BY id ASC'))) {
 echo 'Prepare failed: (' . $mysqli->errno . ') ' . $mysqli->error;
}
if (!$stmt->execute()) {
 echo 'Execute failed: (' . $stmt->errno . ') ' . $stmt->error;
}
if (!($res = $stmt->get_result())) {
 echo 'Getting result set failed: (' . $stmt->errno . ') ' . $stmt->error;
}
var_dump($res->fetch_all());
?>

The above example will output: 

array(1) {
 [0]=>
 array(2) {
 [0]=>
 int(1)
 [1]=>
 string(1) 'a'
 }
}

Using the mysqli_result interface offers the additional benefit of flexible client-side result set navigation.

Example 20.87. Buffered result set for flexible read out

<?php
$mysqli = new mysqli('example.com', 'user', 'password', 'database');
if ($mysqli->connect_errno) {
 echo 'Failed to connect to MySQL: (' . $mysqli->connect_errno . ') ' . $mysqli->connect_error;
}
if (!$mysqli->query('DROP TABLE IF EXISTS test') ||
 !$mysqli->query('CREATE TABLE test(id INT, label CHAR(1))') ||
 !$mysqli->query('INSERT INTO test(id, label) VALUES (1, 'a'), (2, 'b'), (3, 'c')')) {
 echo 'Table creation failed: (' . $mysqli->errno . ') ' . $mysqli->error;
}
if (!($stmt = $mysqli->prepare('SELECT id, label FROM test'))) {
 echo 'Prepare failed: (' . $mysqli->errno . ') ' . $mysqli->error;
}
if (!$stmt->execute()) {
 echo 'Execute failed: (' . $stmt->errno . ') ' . $stmt->error;
}
if (!($res = $stmt->get_result())) {
 echo 'Getting result set failed: (' . $stmt->errno . ') ' . $stmt->error;
}
for ($row_no = ($res->num_rows - 1); $row_no >= 0; $row_no--) {
 $res->data_seek($row_no);
 var_dump($res->fetch_assoc());
}
$res->close();
?>

The above example will output: 

array(2) {
 ['id']=>
 int(3)
 ['label']=>
 string(1) 'c'
}
array(2) {
 ['id']=>
 int(2)
 ['label']=>
 string(1) 'b'
}
array(2) {
 ['id']=>
 int(1)
 ['label']=>
 string(1) 'a'
}

Escaping and SQL injection

Bound variables will be escaped automatically by the server. The server inserts their escaped values at the appropriate places into the statement template before execution. A hint must be provided to the server for the type of bound variable, to create an appropriate conversion. See the mysqli_stmt_bind_param function for more information.

The automatic escaping of values within the server is sometimes considered a security feature to prevent SQL injection. The same degree of security can be achieved with non-prepared statements, if input values are escaped correctly.

Client-side prepared statement emulation

The API does not include emulation for client-side prepared statement emulation.

Quick prepared - non-prepared statement comparison

The table below compares server-side prepared and non-prepared statements.

Prepared Statement Non-prepared statement
Client-server round trips, SELECT, single execution 2 1
Statement string transferred from client to server 1 1
Client-server round trips, SELECT, repeated (n) execution 1 + n n
Statement string transferred from client to server 1 template, n times bound parameter, if any n times together with parameter, if any
Input parameter binding API Yes, automatic input escaping No, manual input escaping
Output variable binding API Yes No
Supports use of mysqli_result API Yes, use mysqli_stmt_get_result Yes
Buffered result sets Yes, use mysqli_stmt_get_result or binding with mysqli_stmt_store_result Yes, default of mysqli_query
Unbuffered result sets Yes, use output binding API Yes, use mysqli_real_query with mysqli_use_result
MySQL Client Server protocol data transfer flavor Binary protocol Text protocol
Result set values SQL data types Preserved when fetching Converted to string or preserved when fetching
Supports all SQL statements Recent MariaDB versions support most but not all Yes

See also

mysqli::__construct
mysqli::query
mysqli::prepare
mysqli_stmt::prepare
mysqli_stmt::execute
mysqli_stmt::bind_param
mysqli_stmt::bind_result
Stored Procedures

The MariaDB database supports stored procedures. A stored procedure is a subroutine stored in the database catalog. Applications can call and execute the stored procedure. The CALL SQL statement is used to execute a stored procedure.

Parameter

Stored procedures can have IN, INOUT and OUT parameters, depending on the MariaDB version. The mysqli interface has no special notion for the different kinds of parameters.

IN parameter

Input parameters are provided with the CALL statement. Please, make sure values are escaped correctly.

Example 20.88. Calling a stored procedure

<?php
$mysqli = new mysqli('example.com', 'user', 'password', 'database');
if ($mysqli->connect_errno) {
 echo 'Failed to connect to MySQL: (' . $mysqli->connect_errno . ') ' . $mysqli->connect_error;
}
if (!$mysqli->query('DROP TABLE IF EXISTS test') || !$mysqli->query('CREATE TABLE test(id INT)')) {
 echo 'Table creation failed: (' . $mysqli->errno . ') ' . $mysqli->error;
}
if (!$mysqli->query('DROP PROCEDURE IF EXISTS p') ||
 !$mysqli->query('CREATE PROCEDURE p(IN id_val INT) BEGIN INSERT INTO test(id) VALUES(id_val); END;')) {
 echo 'Stored procedure creation failed: (' . $mysqli->errno . ') ' . $mysqli->error;
}
if (!$mysqli->query('CALL p(1)')) {
 echo 'CALL failed: (' . $mysqli->errno . ') ' . $mysqli->error;
}
if (!($res = $mysqli->query('SELECT id FROM test'))) {
 echo 'SELECT failed: (' . $mysqli->errno . ') ' . $mysqli->error;
}
var_dump($res->fetch_assoc());
?>

The above example will output: 

array(1) {
 ['id']=>
 string(1) '1'
}

INOUT/OUT parameter

The values of INOUT/OUT parameters are accessed using session variables.

Example 20.89. Using session variables

<?php
$mysqli = new mysqli('example.com', 'user', 'password', 'database');
if ($mysqli->connect_errno) {
 echo 'Failed to connect to MySQL: (' . $mysqli->connect_errno . ') ' . $mysqli->connect_error;
}
if (!$mysqli->query('DROP PROCEDURE IF EXISTS p') ||
 !$mysqli->query('CREATE PROCEDURE p(OUT msg VARCHAR(50)) BEGIN SELECT 'Hi!' INTO msg; END;')) {
 echo 'Stored procedure creation failed: (' . $mysqli->errno . ') ' . $mysqli->error;
}
if (!$mysqli->query('SET @msg = ''') || !$mysqli->query('CALL p(@msg)')) {
 echo 'CALL failed: (' . $mysqli->errno . ') ' . $mysqli->error;
}
if (!($res = $mysqli->query('SELECT @msg as _p_out'))) {
 echo 'Fetch failed: (' . $mysqli->errno . ') ' . $mysqli->error;
}
$row = $res->fetch_assoc();
echo $row['_p_out'];
?>

The above example will output: 

Hi!

Application and framework developers may be able to provide a more convenient API using a mix of session variables and databased catalog inspection. However, please note the possible performance impact of a custom solution based on catalog inspection.

Handling result sets

Stored procedures can return result sets. Result sets returned from a stored procedure cannot be fetched correctly using mysqli_query. The mysqli_query function combines statement execution and fetching the first result set into a buffered result set, if any. However, there are additional stored procedure result sets hidden from the user which cause mysqli_query to fail returning the user expected result sets.

Result sets returned from a stored procedure are fetched using mysqli_real_query or mysqli_multi_query. Both functions allow fetching any number of result sets returned by a statement, such as CALL. Failing to fetch all result sets returned by a stored procedure causes an error.

Example 20.90. Fetching results from stored procedures

<?php
$mysqli = new mysqli('example.com', 'user', 'password', 'database');
if ($mysqli->connect_errno) {
 echo 'Failed to connect to MySQL: (' . $mysqli->connect_errno . ') ' . $mysqli->connect_error;
}
if (!$mysqli->query('DROP TABLE IF EXISTS test') ||
 !$mysqli->query('CREATE TABLE test(id INT)') ||
 !$mysqli->query('INSERT INTO test(id) VALUES (1), (2), (3)')) {
 echo 'Table creation failed: (' . $mysqli->errno . ') ' . $mysqli->error;
}
if (!$mysqli->query('DROP PROCEDURE IF EXISTS p') ||
 !$mysqli->query('CREATE PROCEDURE p() READS SQL DATA BEGIN SELECT id FROM test; SELECT id + 1 FROM test; END;')) {
 echo 'Stored procedure creation failed: (' . $mysqli->errno . ') ' . $mysqli->error;
}
if (!$mysqli->multi_query('CALL p()')) {
 echo 'CALL failed: (' . $mysqli->errno . ') ' . $mysqli->error;
}
do {
 if ($res = $mysqli->store_result()) {
 printf('---\n');
 var_dump($res->fetch_all());
 $res->free();
 } else {
 if ($mysqli->errno) {
 echo 'Store failed: (' . $mysqli->errno . ') ' . $mysqli->error;
 }
 }
} while ($mysqli->more_results() && $mysqli->next_result());
?>

The above example will output: 

---
array(3) {
 [0]=>
 array(1) {
 [0]=>
 string(1) '1'
 }
 [1]=>
 array(1) {
 [0]=>
 string(1) '2'
 }
 [2]=>
 array(1) {
 [0]=>
 string(1) '3'
 }
}
---
array(3) {
 [0]=>
 array(1) {
 [0]=>
 string(1) '2'
 }
 [1]=>
 array(1) {
 [0]=>
 string(1) '3'
 }
 [2]=>
 array(1) {
 [0]=>
 string(1) '4'
 }
}

Use of prepared statements

No special handling is required when using the prepared statement interface for fetching results from the same stored procedure as above. The prepared statement and non-prepared statement interfaces are similar. Please note, that not every MYSQL server version may support preparing the CALL SQL statement.

Example 20.91. Stored Procedures and Prepared Statements

<?php
$mysqli = new mysqli('example.com', 'user', 'password', 'database');
if ($mysqli->connect_errno) {
 echo 'Failed to connect to MySQL: (' . $mysqli->connect_errno . ') ' . $mysqli->connect_error;
}
if (!$mysqli->query('DROP TABLE IF EXISTS test') ||
 !$mysqli->query('CREATE TABLE test(id INT)') ||
 !$mysqli->query('INSERT INTO test(id) VALUES (1), (2), (3)')) {
 echo 'Table creation failed: (' . $mysqli->errno . ') ' . $mysqli->error;
}
if (!$mysqli->query('DROP PROCEDURE IF EXISTS p') ||
 !$mysqli->query('CREATE PROCEDURE p() READS SQL DATA BEGIN SELECT id FROM test; SELECT id + 1 FROM test; END;')) {
 echo 'Stored procedure creation failed: (' . $mysqli->errno . ') ' . $mysqli->error;
}
if (!($stmt = $mysqli->prepare('CALL p()'))) {
 echo 'Prepare failed: (' . $mysqli->errno . ') ' . $mysqli->error;
}
if (!$stmt->execute()) {
 echo 'Execute failed: (' . $stmt->errno . ') ' . $stmt->error;
}
do {
 if ($res = $stmt->get_result()) {
 printf('---\n');
 var_dump(mysqli_fetch_all($res));
 mysqli_free_result($res);
 } else {
 if ($stmt->errno) {
 echo 'Store failed: (' . $stmt->errno . ') ' . $stmt->error;
 }
 }
} while ($stmt->more_results() && $stmt->next_result());
?>

Of course, use of the bind API for fetching is supported as well.

Example 20.92. Stored Procedures and Prepared Statements using bind API

<?php if (!($stmt = $mysqli->prepare('CALL p()'))) {
 echo 'Prepare failed: (' . $mysqli->errno . ') ' . $mysqli->error;
}
if (!$stmt->execute()) {
 echo 'Execute failed: (' . $stmt->errno . ') ' . $stmt->error;
}
do {
 $id_out = NULL;
 if (!$stmt->bind_result($id_out)) {
 echo 'Bind failed: (' . $stmt->errno . ') ' . $stmt->error;
 }
 while ($stmt->fetch()) {
 echo 'id = $id_out\n';
 }
} while ($stmt->more_results() && $stmt->next_result());
?>

See also

mysqli::query
mysqli::multi_query
mysqli_result::next-result
mysqli_result::more-results
Multiple Statements

MySQL optionally allows having multiple statements in one statement string. Sending multiple statements at once reduces client-server round trips but requires special handling.

Multiple statements or multi queries must be executed with mysqli_multi_query. The individual statements of the statement string are separated by semicolon. Then, all result sets returned by the executed statements must be fetched.

The MariaDB server allows having statements that do return result sets and statements that do not return result sets in one multiple statement.

Example 20.93. Multiple Statements

<?php
$mysqli = new mysqli('example.com', 'user', 'password', 'database');
if ($mysqli->connect_errno) {
 echo 'Failed to connect to MySQL: (' . $mysqli->connect_errno . ') ' . $mysqli->connect_error;
}
if (!$mysqli->query('DROP TABLE IF EXISTS test') || !$mysqli->query('CREATE TABLE test(id INT)')) {
 echo 'Table creation failed: (' . $mysqli->errno . ') ' . $mysqli->error;
}
$sql = 'SELECT COUNT(*) AS _num FROM test; ';
$sql.= 'INSERT INTO test(id) VALUES (1); ';
$sql.= 'SELECT COUNT(*) AS _num FROM test; ';
if (!$mysqli->multi_query($sql)) {
 echo 'Multi query failed: (' . $mysqli->errno . ') ' . $mysqli->error;
}
do {
 if ($res = $mysqli->store_result()) {
 var_dump($res->fetch_all(MYSQLI_ASSOC));
 $res->free();
 }
} while ($mysqli->more_results() && $mysqli->next_result());
?>

The above example will output: 

array(1) {
 [0]=>
 array(1) {
 ['_num']=>
 string(1) '0'
 }
}
array(1) {
 [0]=>
 array(1) {
 ['_num']=>
 string(1) '1'
 }
}

Security considerations

The API functions mysqli-query and mysqli_real_query do not set a connection flag necessary for activating multi queries in the server. An extra API call is used for multiple statements to reduce the likeliness of accidental SQL injection attacks. An attacker may try to add statements such as ; DROP DATABASE mysql or ; SELECT SLEEP(999). If the attacker succeeds in adding SQL to the statement string but mysqli_multi_query is not used, the server will not execute the second, injected and malicious SQL statement.

Example 20.94. SQL Injection

<?php
$mysqli = new mysqli('example.com', 'user', 'password', 'database');
$res = $mysqli->query('SELECT 1; DROP TABLE mysql.user');
if (!$res) {
 echo 'Error executing query: (' . $mysqli->errno . ') ' . $mysqli->error;
}
?>

The above example will output: 

Error executing query: (1064) You have an error in your SQL syntax;
check the manual that corresponds to your MariaDB server version for the right syntax 
to use near 'DROP TABLE mysql.user' at line 1

Prepared statements

Use of the multiple statement with prepared statements is not supported.

See also

mysqli::query
mysqli::multi_query
mysqli_result::next-result
mysqli_result::more-results
API support for transactions

The MariaDB server supports transactions depending on the storage engine used. Since MariaDB 5.5, the default storage engine is InnoDB. InnoDB has full ACID transaction support.

Transactions can either be controlled using SQL or API calls. It is recommended to use API calls for enabling and disabling the auto commit mode and for committing and rolling back transactions.

Example 20.95. Setting auto commit mode with SQL and through the API

<?php
$mysqli = new mysqli('example.com', 'user', 'password', 'database');
if ($mysqli->connect_errno) {
 echo 'Failed to connect to MySQL: (' . $mysqli->connect_errno . ') ' . $mysqli->connect_error;
}
/* Recommended: using API to control transactional settings */
$mysqli->autocommit(false);
/* Won't be monitored and recognized by the replication and the load balancing plugin */
if (!$mysqli->query('SET AUTOCOMMIT = 0')) {
 echo 'Query failed: (' . $mysqli->errno . ') ' . $mysqli->error;
}
?>

Optional feature packages, such as the replication and load balancing plugin, can easily monitor API calls. The replication plugin offers transaction aware load balancing, if transactions are controlled with API calls. Transaction aware load balancing is not available if SQL statements are used for setting auto commit mode, committing or rolling back a transaction.

Example 20.96. Commit and rollback

<?php
$mysqli = new mysqli('example.com', 'user', 'password', 'database');
$mysqli->autocommit(false);
$mysqli->query('INSERT INTO test(id) VALUES (1)');
$mysqli->rollback();
$mysqli->query('INSERT INTO test(id) VALUES (2)');
$mysqli->commit();
?>

Please note, that the MariaDB server cannot roll back all statements. Some statements cause am implicit commit.

See also

mysqli::autocommit
mysqli_result::commit
mysqli_result::rollback
Metadata

A MariaDB result set contains metadata. The metadata describes the columns found in the result set. All metadata send by MariaDB is accessible through the mysqli interface. The extension performs no or negligible changes to the information it receives. Differences between MariaDB server versions are not aligned.

Meta data is access through the mysqli_result interface.

Example 20.97. Accessing result set meta data

<?php
$mysqli = new mysqli('example.com', 'user', 'password', 'database');
if ($mysqli->connect_errno) {
 echo 'Failed to connect to MySQL: (' . $mysqli->connect_errno . ') ' . $mysqli->connect_error;
}
$res = $mysqli->query('SELECT 1 AS _one, 'Hello' AS _two FROM DUAL');
var_dump($res->fetch_fields());
?>

The above example will output: 

array(2) {
 [0]=>
 object(stdClass)#3 (13) {
 ['name']=>
 string(4) '_one'
 ['orgname']=>
 string(0) ''
 ['table']=>
 string(0) ''
 ['orgtable']=>
 string(0) ''
 ['def']=>
 string(0) ''
 ['db']=>
 string(0) ''
 ['catalog']=>
 string(3) 'def'
 ['max_length']=>
 int(1)
 ['length']=>
 int(1)
 ['charsetnr']=>
 int(63)
 ['flags']=>
 int(32897)
 ['type']=>
 int(8)
 ['decimals']=>
 int(0)
 }
 [1]=>
 object(stdClass)#4 (13) {
 ['name']=>
 string(4) '_two'
 ['orgname']=>
 string(0) ''
 ['table']=>
 string(0) ''
 ['orgtable']=>
 string(0) ''
 ['def']=>
 string(0) ''
 ['db']=>
 string(0) ''
 ['catalog']=>
 string(3) 'def'
 ['max_length']=>
 int(5)
 ['length']=>
 int(5)
 ['charsetnr']=>
 int(8)
 ['flags']=>
 int(1)
 ['type']=>
 int(253)
 ['decimals']=>
 int(31)
 }
}

Prepared statements

Meta data of result sets created using prepared statements are accessed the same way. A suitable mysqli_result handle is returned by mysqli_stmt_result_metadata.

Example 20.98. Prepared statements metadata

<?php
$stmt = $mysqli->prepare('SELECT 1 AS _one, 'Hello' AS _two FROM DUAL');
$stmt->execute();
$res = $stmt->result_metadata();
var_dump($res->fetch_fields());
?>

See also

mysqli::query
mysqli_result::fetch_fields

Installing/Configuring

Requirements
Installation
Runtime Configuration
Resource Types
Requirements

In order to have these functions available, you must compile PHP with support for the mysqli extension.Note

The mysqli extension is designed to work with MariaDB version 4.1.13 or newer, or 5.0.7 or newer. For previous versions, please see the MySQL extension documentation.

Installation
Installation on Linux
Installation on Windows Systems

The mysqli extension was introduced with PHP version 5.0.0. The MariaDB Native Driver was included in PHP version 5.3.0.

Installation on Linux

The common Unix distributions include binary versions of PHP that can be installed. Although these binary versions are typically built with support for MariaDB extensions enabled, the extension libraries themselves may need to be installed using an additional package. Check the package manager than comes with your chosen distribution for availability.

Unless your Unix distribution comes with a binary package of PHP with the mysqli extension available, you will need to build PHP from source code. Building PHP from source allows you to specify the MariaDB extensions you want to use, as well as your choice of client library for each extension.

The MariaDB Native Driver is the recommended option, as it results in improved performance and gives access to features not available when using the MariaDB Client Library. Refer to What is PHP's MariaDB Native Driver? for a brief overview of the advantages of MariaDB Native Driver.

The /path/to/mysql_config represents the location of the mysql_config program that comes with MariaDB Server.

Table 20.12. mysqli compile time support matrix

PHP Version Default Configure Options: mysqlnd Configure Options: libmysql Changelog
5.0.x, 5.1.x, 5.2.x libmysql Not Available --with-mysqli=/path/to/mysql_config
5.3.x libmysql --with-mysqli=mysqlnd --with-mysqli=/path/to/mysql_config mysqlnd is now supported
5.4.x mysqlnd --with-mysqli --with-mysqli=/path/to/mysql_config mysqlnd is now the default

Note that it is possible to freely mix MariaDB extensions and client libraries. For example, it is possible to enable the MariaDB extension to use the MariaDB Client Library (libmysql), while configuring the mysqli extension to use the MariaDB Native Driver. However, all permutations of extension and client library are possible.

The following example builds the MariaDB extension to use the MariaDB Client Library, and the mysqli and PDO MYSQL extensions to use the MariaDB Native Driver: 

./configure --with-mysql=/usr/bin/mysql_config \
--with-mysqli=mysqlnd \
--with-pdo-mysql=mysqlnd
[other options]
Installation on Windows Systems
PHP 5.0, 5.1, 5.2
PHP 5.3.0+

On Windows, PHP is most commonly installed using the binary installer.

PHP 5.0, 5.1, 5.2

Once PHP has been installed, some configuration is required to enable mysqli and specify the client library you want it to use.

The mysqli extension is not enabled by default, so the php_mysqli.dll DLL must be enabled inside of php.ini. In order to do this you need to find the php.ini file (typically located in c:\php), and make sure you remove the comment (semi-colon) from the start of the line extension=php_mysqli.dll, in the section marked [PHP_MYSQLI].

Also, if you want to use the MariaDB Client Library with mysqli, you need to make sure PHP can access the client library file. The MariaDB Client Library is included as a file named libmysql.dll in the Windows PHP distribution. This file needs to be available in the Windows system's PATH environment variable, so that it can be successfully loaded. See the FAQ titled 'How do I add my PHP directory to the PATH on Windows' for information on how to do this. Copying libmysql.dll to the Windows system directory (typically c:\Windows\system) also works, as the system directory is by default in the system's PATH. However, this practice is strongly discouraged.

As with enabling any PHP extension (such as php_mysqli.dll), the PHP directive extension_dir should be set to the directory where the PHP extensions are located. See also the Manual Windows Installation Instructions. An example extension_dir value for PHP 5 is c:\php\ext.Note

If when starting the web server an error similar to the following occurs: 'Unable to load dynamic library './php_mysqli.dll'', this is because php_mysqli.dll and/or libmysql.dll cannot be found by the system.

PHP 5.3.0+

On Windows, for PHP versions 5.3 and newer, the mysqli extension is enabled and uses the MariaDB Native Driver by default. This means you don't need to worry about configuring access to libmysql.dll.

Runtime Configuration

The behaviour of these functions is affected by settings in php.ini.

Table 20.13. MySQLi Configuration Options

Name Default Changeable Changelog
mysqli.allow_local_infile '1' PHP_INI_SYSTEM Available since PHP 5.2.4.
mysqli.allow_persistent '1' PHP_INI_SYSTEM Available since PHP 5.3.0.
mysqli.max_persistent '-1' PHP_INI_SYSTEM Available since PHP 5.3.0.
mysqli.max_links '-1' PHP_INI_SYSTEM Available since PHP 5.0.0.
mysqli.default_port '3306' PHP_INI_ALL Available since PHP 5.0.0.
mysqli.default_socket NULL PHP_INI_ALL Available since PHP 5.0.0.
mysqli.default_host NULL PHP_INI_ALL Available since PHP 5.0.0.
mysqli.default_user NULL PHP_INI_ALL Available since PHP 5.0.0.
mysqli.default_pw NULL PHP_INI_ALL Available since PHP 5.0.0.
mysqli.reconnect '0' PHP_INI_SYSTEM Available since PHP 4.3.5.
mysqli.cache_size '2000' PHP_INI_SYSTEM Available since PHP 5.3.0.

For further details and definitions of the preceding PHP_INI_* constants, see the chapter on configuration changes.

Here's a short explanation of the configuration directives.

mysqli.allow_local_infile integer

Allow accessing, from PHP's perspective, local files with LOAD DATA statements

mysqli.allow_persistent integer

Enable the ability to create persistent connections using mysqli_connect.

mysqli.max_persistent integer

Maximum of persistent connections that can be made. Set to 0 for unlimited.

mysqli.max_links integer

The maximum number of MariaDB connections per process.

mysqli.default_port integer

The default TCP port number to use when connecting to the database server if no other port is specified. If no default is specified, the port will be obtained from the MYSQL_TCP_PORT environment variable, the mysql-tcp entry in /etc/services or the compile-time MYSQL_PORT constant, in that order. Win32 will only use the MYSQL_PORT constant.

mysqli.default_socket string

The default socket name to use when connecting to a local database server if no other socket name is specified.

mysqli.default_host string

The default server host to use when connecting to the database server if no other host is specified. Doesn't apply in safe mode.

mysqli.default_user string

The default user name to use when connecting to the database server if no other name is specified. Doesn't apply in safe mode.

mysqli.default_pw string

The default password to use when connecting to the database server if no other password is specified. Doesn't apply in safe mode.

mysqli.reconnect integer

Automatically reconnect if the connection was lost.

mysqli.cache_size integer

Available only with mysqlnd.

Users cannot set MYSQL_OPT_READ_TIMEOUT through an API call or runtime configuration setting. Note that if it were possible there would be differences between how libmysql and streams would interpret the value of MYSQL_OPT_READ_TIMEOUT.

Resource Types

This extension has no resource types defined.

The mysqli Extension and Persistent Connections

Persistent connection support was introduced in PHP 5.3 for the mysqli extension. Support was already present in PDO MYSQL and ext/mysql. The idea behind persistent connections is that a connection between a client process and a database can be reused by a client process, rather than being created and destroyed multiple times. This reduces the overhead of creating fresh connections every time one is required, as unused connections are cached and ready to be reused.

Unlike the mysql extension, mysqli does not provide a separate function for opening persistent connections. To open a persistent connection you must prepend p: to the hostname when connecting.

The problem with persistent connections is that they can be left in unpredictable states by clients. For example, a table lock might be activated before a client terminates unexpectedly. A new client process reusing this persistent connection will get the connection "as is". Any cleanup would need to be done by the new client process before it could make good use of the persistent connection, increasing the burden on the programmer.

The persistent connection of the mysqli extension however provides built-in cleanup handling code. The cleanup carried out by mysqli includes:

This ensures that persistent connections are in a clean state on return from the connection pool, before the client process uses them.

The mysqli extension does this cleanup by automatically calling the C-API function mysql_change_user().

The automatic cleanup feature has advantages and disadvantages though. The advantage is that the programmer no longer needs to worry about adding cleanup code, as it is called automatically. However, the disadvantage is that the code could potentially be a little slower, as the code to perform the cleanup needs to run each time a connection is returned from the connection pool.

It is possible to switch off the automatic cleanup code, by compiling PHP with MYSQLI_NO_CHANGE_USER_ON_PCONNECT defined.Note

The mysqli extension supports persistent connections when using either MariaDB Native Driver or MariaDB Client Library.

Predefined Constants

The constants below are defined by this extension, and will only be available when the extension has either been compiled into PHP or dynamically loaded at runtime.

MYSQLI_READ_DEFAULT_GROUP

Read options from the named group from my.cnf or the file specified with MYSQLI_READ_DEFAULT_FILE

MYSQLI_READ_DEFAULT_FILE

Read options from the named option file instead of from my.cnf

MYSQLI_OPT_CONNECT_TIMEOUT

Connect timeout in seconds

MYSQLI_OPT_LOCAL_INFILE

Enables command LOAD LOCAL INFILE

MYSQLI_INIT_COMMAND

Command to execute when connecting to MariaDB server. Will automatically be re-executed when reconnecting.

MYSQLI_CLIENT_SSL

Use SSL (encrypted protocol). This option should not be set by application programs; it is set internally in the MariaDB client library

MYSQLI_CLIENT_COMPRESS

Use compression protocol

MYSQLI_CLIENT_INTERACTIVE

Allow interactive_timeout seconds (instead of wait_timeout seconds) of inactivity before closing the connection. The client's session wait_timeout variable will be set to the value of the session interactive_timeout variable.

MYSQLI_CLIENT_IGNORE_SPACE

Allow spaces after function names. Makes all functions names reserved words.

MYSQLI_CLIENT_NO_SCHEMA

Don't allow the db_name.tbl_name.col_name syntax.

MYSQLI_CLIENT_MULTI_QUERIES

Allows multiple semicolon-delimited queries in a single mysqli_query call.

MYSQLI_STORE_RESULT

For using buffered resultsets

MYSQLI_USE_RESULT

For using unbuffered resultsets

MYSQLI_ASSOC

Columns are returned into the array having the fieldname as the array index.

MYSQLI_NUM

Columns are returned into the array having an enumerated index.

MYSQLI_BOTH

Columns are returned into the array having both a numerical index and the fieldname as the associative index.

MYSQLI_NOT_NULL_FLAG

Indicates that a field is defined as NOT NULL

MYSQLI_PRI_KEY_FLAG

Field is part of a primary index

MYSQLI_UNIQUE_KEY_FLAG

Field is part of a unique index.

MYSQLI_MULTIPLE_KEY_FLAG

Field is part of an index.

MYSQLI_BLOB_FLAG

Field is defined as BLOB

MYSQLI_UNSIGNED_FLAG

Field is defined as UNSIGNED

MYSQLI_ZEROFILL_FLAG

Field is defined as ZEROFILL

MYSQLI_AUTO_INCREMENT_FLAG

Field is defined as AUTO_INCREMENT

MYSQLI_TIMESTAMP_FLAG

Field is defined as TIMESTAMP

MYSQLI_SET_FLAG

Field is defined as SET

MYSQLI_NUM_FLAG

Field is defined as NUMERIC

MYSQLI_PART_KEY_FLAG

Field is part of an multi-index

MYSQLI_GROUP_FLAG

Field is part of GROUP BY

MYSQLI_TYPE_DECIMAL

Field is defined as DECIMAL

MYSQLI_TYPE_NEWDECIMAL

Precision math DECIMAL or NUMERIC field (MySQL 5.0.3 and up)

MYSQLI_TYPE_BIT

Field is defined as BIT (MySQL 5.0.3 and up)

MYSQLI_TYPE_TINY

Field is defined as TINYINT

MYSQLI_TYPE_SHORT

Field is defined as SMALLINT

MYSQLI_TYPE_LONG

Field is defined as INT

MYSQLI_TYPE_FLOAT

Field is defined as FLOAT

MYSQLI_TYPE_DOUBLE

Field is defined as DOUBLE

MYSQLI_TYPE_NULL

Field is defined as DEFAULT NULL

MYSQLI_TYPE_TIMESTAMP

Field is defined as TIMESTAMP

MYSQLI_TYPE_LONGLONG

Field is defined as BIGINT

MYSQLI_TYPE_INT24

Field is defined as MEDIUMINT

MYSQLI_TYPE_DATE

Field is defined as DATE

MYSQLI_TYPE_TIME

Field is defined as TIME

MYSQLI_TYPE_DATETIME

Field is defined as DATETIME

MYSQLI_TYPE_YEAR

Field is defined as YEAR

MYSQLI_TYPE_NEWDATE

Field is defined as DATE

MYSQLI_TYPE_INTERVAL

Field is defined as INTERVAL

MYSQLI_TYPE_ENUM

Field is defined as ENUM

MYSQLI_TYPE_SET

Field is defined as SET

MYSQLI_TYPE_TINY_BLOB

Field is defined as TINYBLOB

MYSQLI_TYPE_MEDIUM_BLOB

Field is defined as MEDIUMBLOB

MYSQLI_TYPE_LONG_BLOB

Field is defined as LONGBLOB

MYSQLI_TYPE_BLOB

Field is defined as BLOB

MYSQLI_TYPE_VAR_STRING

Field is defined as VARCHAR

MYSQLI_TYPE_STRING

Field is defined as STRING

MYSQLI_TYPE_CHAR

Field is defined as CHAR

MYSQLI_TYPE_GEOMETRY

Field is defined as GEOMETRY

MYSQLI_NEED_DATA

More data available for bind variable

MYSQLI_NO_DATA

No more data available for bind variable

MYSQLI_DATA_TRUNCATED

Data truncation occurred. Available since PHP 5.1.0 and MariaDB 5.0.5.

MYSQLI_ENUM_FLAG

Field is defined as ENUM. Available since PHP 5.3.0.

MYSQLI_CURSOR_TYPE_FOR_UPDATE
MYSQLI_CURSOR_TYPE_NO_CURSOR
MYSQLI_CURSOR_TYPE_READ_ONLY
MYSQLI_CURSOR_TYPE_SCROLLABLE
MYSQLI_STMT_ATTR_CURSOR_TYPE
MYSQLI_STMT_ATTR_PREFETCH_ROWS
MYSQLI_STMT_ATTR_UPDATE_MAX_LENGTH
MYSQLI_SET_CHARSET_NAME
MYSQLI_REPORT_INDEX

Report if no index or bad index was used in a query.

MYSQLI_REPORT_ERROR

Report errors from mysqli function calls.

MYSQLI_REPORT_STRICT

Throw a mysqli_sql_exception for errors instead of warnings.

MYSQLI_REPORT_ALL

Set all options on (report all).

MYSQLI_REPORT_OFF

Turns reporting off.

MYSQLI_DEBUG_TRACE_ENABLED

Is set to 1 if mysqli_debug functionality is enabled.

MYSQLI_SERVER_QUERY_NO_GOOD_INDEX_USED
MYSQLI_SERVER_QUERY_NO_INDEX_USED
MYSQLI_REFRESH_GRANT

Refreshes the grant tables.

MYSQLI_REFRESH_LOG

Flushes the logs, like executing the FLUSH LOGS SQL statement.

MYSQLI_REFRESH_TABLES

Flushes the table cache, like executing the FLUSH TABLES SQL statement.

MYSQLI_REFRESH_HOSTS

Flushes the host cache, like executing the FLUSH HOSTS SQL statement.

MYSQLI_REFRESH_STATUS

Reset the status variables, like executing the FLUSH STATUS SQL statement.

MYSQLI_REFRESH_THREADS

Flushes the thread cache.

MYSQLI_REFRESH_SLAVE

On a slave replication server: resets the master server information, and restarts the slave. Like executing the RESET SLAVE SQL statement.

MYSQLI_REFRESH_MASTER

On a master replication server: removes the binary log files listed in the binary log index, and truncates the index file. Like executing the RESET MASTER SQL statement.

Notes

Some implementation notes:

  1. Support was added for MYSQL_TYPE_GEOMETRY to the MySQLi extension in PHP 5.3.
  2. Note there are different internal implementations within libmysql and mysqlnd for handling columns of type MYSQL_TYPE_GEOMETRY. Generally speaking, mysqlnd will allocate significantly less memory. For example, if there is a POINT column in a result set, libmysql may pre-allocate up to 4GB of RAM although less than 50 bytes are needed for holding a POINT column in memory. Memory allocation is much lower, less than 50 bytes, if using mysqlnd.

The MySQLi Extension Function Summary

mysqli Class
OOP Interface Procedural Interface Alias (Do not use) Description
Properties
$mysqli::affected_rows mysqli_affected_rows N/A Gets the number of affected rows in a previous MariaDB operation
$mysqli::client_info mysqli_get_client_info N/A Returns the MariaDB client version as a string
$mysqli::client_version mysqli_get_client_version N/A Returns MariaDB client version info as an integer
$mysqli::connect_errno mysqli_connect_errno N/A Returns the error code from last connect call
$mysqli::connect_error mysqli_connect_error N/A Returns a string description of the last connect error
$mysqli::errno mysqli_errno N/A Returns the error code for the most recent function call
$mysqli::error mysqli_error N/A Returns a string description of the last error
$mysqli::field_count mysqli_field_count N/A Returns the number of columns for the most recent query
$mysqli::host_info mysqli_get_host_info N/A Returns a string representing the type of connection used
$mysqli::protocol_version mysqli_get_proto_info N/A Returns the version of the MariaDB protocol used
$mysqli::server_info mysqli_get_server_info N/A Returns the version of the MariaDB server
$mysqli::server_version mysqli_get_server_version N/A Returns the version of the MariaDB server as an integer
$mysqli::info mysqli_info N/A Retrieves information about the most recently executed query
$mysqli::insert_id mysqli_insert_id N/A Returns the auto generated id used in the last query
$mysqli::sqlstate mysqli_sqlstate N/A Returns the SQLSTATE error from previous MariaDB operation
$mysqli::warning_count mysqli_warning_count N/A Returns the number of warnings from the last query for the given link
Methods
mysqli::autocommit mysqli_autocommit N/A Turns on or off auto-commiting database modifications
mysqli::change_user mysqli_change_user N/A Changes the user of the specified database connection
mysqli::character_set_name, mysqli::client_encoding mysqli_character_set_name mysqli_client_encoding Returns the default character set for the database connection
mysqli::close mysqli_close N/A Closes a previously opened database connection
mysqli::commit mysqli_commit N/A Commits the current transaction
mysqli::__construct mysqli_connect N/A Open a new connection to the MariaDB server [Note: static (i.e. class) method]
mysqli::debug mysqli_debug N/A Performs debugging operations
mysqli::dump_debug_info mysqli_dump_debug_info N/A Dump debugging information into the log
mysqli::get_charset mysqli_get_charset N/A Returns a character set object
mysqli::get_connection_stats mysqli_get_connection_stats N/A Returns client connection statistics. Available only with mysqlnd.
mysqli::get_client_info mysqli_get_client_info N/A Returns the MariaDB client version as a string
mysqli::get_client_stats mysqli_get_client_stats N/A Returns client per-process statistics. Available only with mysqlnd.
mysqli::get_cache_stats mysqli_get_cache_stats N/A Returns client Zval cache statistics. Available only with mysqlnd.
mysqli::get_server_info mysqli_get_server_info N/A NOT DOCUMENTED
mysqli::get_warnings mysqli_get_warnings N/A NOT DOCUMENTED
mysqli::init mysqli_init N/A Initializes MySQLi and returns a resource for use with mysqli_real_connect. [Not called on an object, as it returns a $mysqli object.]
mysqli::kill mysqli_kill N/A Asks the server to kill a MariaDB thread
mysqli::more_results mysqli_more_results N/A Check if there are any more query results from a multi query
mysqli::multi_query mysqli_multi_query N/A Performs a query on the database
mysqli::next_result mysqli_next_result N/A Prepare next result from multi_query
mysqli::options mysqli_options mysqli_set_opt Set options
mysqli::ping mysqli_ping N/A Pings a server connection, or tries to reconnect if the connection has gone down
mysqli::prepare mysqli_prepare N/A Prepare an SQL statement for execution
mysqli::query mysqli_query N/A Performs a query on the database
mysqli::real_connect mysqli_real_connect N/A Opens a connection to a mysql server
mysqli::real_escape_string, mysqli::escape_string mysqli_real_escape_string mysqli_escape_string Escapes special characters in a string for use in an SQL statement, taking into account the current charset of the connection
mysqli::real_query mysqli_real_query N/A Execute an SQL query
mysqli::refresh mysqli_refresh N/A Flushes tables or caches, or resets the replication server information
mysqli::rollback mysqli_rollback N/A Rolls back current transaction
mysqli::select_db mysqli_select_db N/A Selects the default database for database queries
mysqli::set_charset mysqli_set_charset N/A Sets the default client character set
mysqli::set_local_infile_default mysqli_set_local_infile_default N/A Unsets user defined handler for load local infile command
mysqli::set_local_infile_handler mysqli_set_local_infile_handler N/A Set callback function for LOAD DATA LOCAL INFILE command
mysqli::ssl_set mysqli_ssl_set N/A Used for establishing secure connections using SSL
mysqli::stat mysqli_stat N/A Gets the current system status
mysqli::stmt_init mysqli_stmt_init N/A Initializes a statement and returns an object for use with mysqli_stmt_prepare
mysqli::store_result mysqli_store_result N/A Transfers a result set from the last query
mysqli::thread_id mysqli_thread_id N/A Returns the thread ID for the current connection
mysqli::thread_safe mysqli_thread_safe N/A Returns whether thread safety is given or not
mysqli::use_result mysqli_use_result N/A Initiate a result set retrieval
MySQL_STMT
OOP Interface Procedural Interface Alias (Do not use) Description
Properties
$mysqli_stmt::affected_rows mysqli_stmt_affected_rows N/A Returns the total number of rows changed, deleted, or inserted by the last executed statement
$mysqli_stmt::errno mysqli_stmt_errno N/A Returns the error code for the most recent statement call
$mysqli_stmt::error mysqli_stmt_error N/A Returns a string description for last statement error
$mysqli_stmt::field_count mysqli_stmt_field_count N/A Returns the number of field in the given statement - not documented
$mysqli_stmt::insert_id mysqli_stmt_insert_id N/A Get the ID generated from the previous INSERT operation
$mysqli_stmt::num_rows mysqli_stmt_num_rows N/A Return the number of rows in statements result set
$mysqli_stmt::param_count mysqli_stmt_param_count mysqli_param_count Returns the number of parameter for the given statement
$mysqli_stmt::sqlstate mysqli_stmt_sqlstate N/A Returns SQLSTATE error from previous statement operation
Methods
mysqli_stmt::attr_get mysqli_stmt_attr_get N/A Used to get the current value of a statement attribute
mysqli_stmt::attr_set mysqli_stmt_attr_set N/A Used to modify the behavior of a prepared statement
mysqli_stmt::bind_param mysqli_stmt_bind_param mysqli_bind_param Binds variables to a prepared statement as parameters
mysqli_stmt::bind_result mysqli_stmt_bind_result mysqli_bind_result Binds variables to a prepared statement for result storage
mysqli_stmt::close mysqli_stmt_close N/A Closes a prepared statement
mysqli_stmt::data_seek mysqli_stmt_data_seek N/A Seeks to an arbitrary row in statement result set
mysqli_stmt::execute mysqli_stmt_execute mysqli_execute Executes a prepared Query
mysqli_stmt::fetch mysqli_stmt_fetch mysqli_fetch Fetch results from a prepared statement into the bound variables
mysqli_stmt::free_result mysqli_stmt_free_result N/A Frees stored result memory for the given statement handle
mysqli_stmt::get_result mysqli_stmt_get_result N/A Gets a result set from a prepared statement. Available only with mysqlnd.
mysqli_stmt::get_warnings mysqli_stmt_get_warnings N/A NOT DOCUMENTED
$mysqli_stmt::more_results() mysqli_stmt_more_results() N/A NOT DOCUMENTED Available only with mysqlnd.
$mysqli_stmt::next_result() mysqli_stmt_next_result() N/A NOT DOCUMENTED Available only with mysqlnd.
mysqli_stmt::num_rows mysqli_stmt_num_rows N/A See also property $mysqli_stmt::num_rows
mysqli_stmt::prepare mysqli_stmt_prepare N/A Prepare an SQL statement for execution
mysqli_stmt::reset mysqli_stmt_reset N/A Resets a prepared statement
mysqli_stmt::result_metadata mysqli_stmt_result_metadata mysqli_get_metadata Returns result set metadata from a prepared statement
mysqli_stmt::send_long_data mysqli_stmt_send_long_data mysqli_send_long_data Send data in blocks
mysqli_stmt::store_result mysqli_stmt_store_result N/A Transfers a result set from a prepared statement
mysqli_result
OOP Interface Procedural Interface Alias (Do not use) Description
Properties
$mysqli_result::current_field mysqli_field_tell N/A Get current field offset of a result pointer
$mysqli_result::field_count mysqli_num_fields N/A Get the number of fields in a result
$mysqli_result::lengths mysqli_fetch_lengths N/A Returns the lengths of the columns of the current row in the result set
$mysqli_result::num_rows mysqli_num_rows N/A Gets the number of rows in a result
Methods
mysqli_result::data_seek mysqli_data_seek N/A Adjusts the result pointer to an arbitary row in the result
mysqli_result::fetch_all mysqli_fetch_all N/A Fetches all result rows and returns the result set as an associative array, a numeric array, or both. Available only with mysqlnd.
mysqli_result::fetch_array mysqli_fetch_array N/A Fetch a result row as an associative, a numeric array, or both
mysqli_result::fetch_assoc mysqli_fetch_assoc N/A Fetch a result row as an associative array
mysqli_result::fetch_field_direct mysqli_fetch_field_direct N/A Fetch meta-data for a single field
mysqli_result::fetch_field mysqli_fetch_field N/A Returns the next field in the result set
mysqli_result::fetch_fields mysqli_fetch_fields N/A Returns an array of objects representing the fields in a result set
mysqli_result::fetch_object mysqli_fetch_object N/A Returns the current row of a result set as an object
mysqli_result::fetch_row mysqli_fetch_row N/A Get a result row as an enumerated array
mysqli_result::field_seek mysqli_field_seek N/A Set result pointer to a specified field offset
mysqli_result::free, mysqli_result::close, mysqli_result::free_result mysqli_free_result N/A Frees the memory associated with a result
MySQL_Driver
OOP Interface Procedural Interface Alias (Do not use) Description
Properties
N/A
Methods
mysqli_driver::embedded_server_end mysqli_embedded_server_end N/A NOT DOCUMENTED
mysqli_driver::embedded_server_start mysqli_embedded_server_start N/A NOT DOCUMENTED
Note

Alias functions are provided for backward compatibility purposes only. Do not use them in new projects.

The mysqli class (mysqli)

mysqli::$affected_rows, mysqli_affected_rows
mysqli::autocommit, mysqli_autocommit
mysqli::change_user, mysqli_change_user
mysqli::character_set_name, mysqli_character_set_name
mysqli::$client_info, mysqli_get_client_info
mysqli::$client_version, mysqli_get_client_version
mysqli::close, mysqli_close
mysqli::commit, mysqli_commit
mysqli::$connect_errno, mysqli_connect_errno
mysqli::$connect_error, mysqli_connect_error
mysqli::__construct, mysqli_connect
mysqli::debug, mysqli_debug
mysqli::disable_reads_from_master, mysqli_disable_reads_from_master
mysqli::dump_debug_info, mysqli_dump_debug_info
mysqli::$errno, mysqli_errno
mysqli::$error_list, mysqli_error_list
mysqli::$error, mysqli_error
mysqli::$field_count, mysqli_field_count
mysqli::get_charset, mysqli_get_charset
mysqli::get_client_info, mysqli_get_client_info
mysqli_get_client_stats
mysqli::$client_version, mysqli_get_client_version
mysqli::get_connection_stats, mysqli_get_connection_stats
mysqli::$host_info, mysqli_get_host_info
mysqli::$protocol_version, mysqli_get_proto_info
mysqli::$server_info, mysqli_get_server_info
mysqli::$server_version, mysqli_get_server_version
mysqli::get_warnings, mysqli_get_warnings
mysqli::$info, mysqli_info
mysqli::init, mysqli_init
mysqli::$insert_id, mysqli_insert_id
mysqli::kill, mysqli_kill
mysqli::more_results, mysqli_more_results
mysqli::multi_query, mysqli_multi_query
mysqli::next_result, mysqli_next_result
mysqli::options, mysqli_options
mysqli::ping, mysqli_ping
mysqli::poll, mysqli_poll
mysqli::prepare, mysqli_prepare
mysqli::query, mysqli_query
mysqli::real_connect, mysqli_real_connect
mysqli::real_escape_string, mysqli_real_escape_string
mysqli::real_query, mysqli_real_query
mysqli::reap_async_query, mysqli_reap_async_query
mysqli::refresh, mysqli_refresh
mysqli::rollback, mysqli_rollback
mysqli::rpl_query_type, mysqli_rpl_query_type
mysqli::select_db, mysqli_select_db
mysqli::send_query, mysqli_send_query
mysqli::set_charset, mysqli_set_charset
mysqli::set_local_infile_default, mysqli_set_local_infile_default
mysqli::set_local_infile_handler, mysqli_set_local_infile_handler
mysqli::$sqlstate, mysqli_sqlstate
mysqli::ssl_set, mysqli_ssl_set
mysqli::stat, mysqli_stat
mysqli::stmt_init, mysqli_stmt_init
mysqli::store_result, mysqli_store_result
mysqli::$thread_id, mysqli_thread_id
mysqli::thread_safe, mysqli_thread_safe
mysqli::use_result, mysqli_use_result
mysqli::$warning_count, mysqli_warning_count

Represents a connection between PHP and a MariaDB database. 

 mysqli {

 mysqli
 Properties int mysqli->affected_rows ;

 string mysqli->client_info ;

 int mysqli->client_version ;

 string mysqli->connect_errno ;

 string mysqli->connect_error ;

 int mysqli->errno ;

 array mysqli->error_list ;

 string mysqli->error ;

 int mysqli->field_count ;

 int mysqli->client_version ;

 string mysqli->host_info ;

 string mysqli->protocol_version ;

 string mysqli->server_info ;

 int mysqli->server_version ;

 string mysqli->info ;

 mixed mysqli->insert_id ;

 string mysqli->sqlstate ;

 int mysqli->thread_id ;

 int mysqli->warning_count ;

Methods bool mysqli::autocommit(bool mode);

 bool mysqli::change_user(string user,

 string password,

 string database);

 string mysqli::character_set_name();

 bool mysqli::close();

 bool mysqli::commit();

 bool mysqli::debug(string message);

 void mysqli::disable_reads_from_master();

 bool mysqli::dump_debug_info();

 object mysqli::get_charset();

 string mysqli::get_client_info();

 bool mysqli::get_connection_stats();

 mysqli_warning mysqli::get_warnings();

 mysqli mysqli::init();

 bool mysqli::kill(int processid);

 bool mysqli::more_results();

 bool mysqli::multi_query(string query);

 bool mysqli::next_result();

 bool mysqli::options(int option,

 mixed value);

 bool mysqli::ping();

 public int mysqli::poll(array read,

 array error,

 array reject,

 int sec,

 int usec);

 mysqli_stmt mysqli::prepare(string query);

 mixed mysqli::query(string query,

 int resultmode= =MYSQLI_STORE_RESULT);

 bool mysqli::real_connect(string host,

 string username,

 string passwd,

 string dbname,

 int port,

 string socket,

 int flags);

 string mysqli::escape_string(string escapestr);

 bool mysqli::real_query(string query);

 public mysqli_result mysqli::reap_async_query();

 public bool mysqli::refresh(int options);

 bool mysqli::rollback();

 int mysqli::rpl_query_type(string query);

 bool mysqli::select_db(string dbname);

 bool mysqli::send_query(string query);

 bool mysqli::set_charset(string charset);

 bool mysqli::set_local_infile_handler(mysqli link,

 callable read_func);

 bool mysqli::ssl_set(string key,

 string cert,

 string ca,

 string capath,

 string cipher);

 string mysqli::stat();

 mysqli_stmt mysqli::stmt_init();

 mysqli_result mysqli::store_result();

 mysqli_result mysqli::use_result();

}
mysqli::$affected_rows, mysqli_affected_rows

Description

Object oriented styleint mysqli->affected_rows ;

Procedural styleint mysqli_affected_rows(mysqli link);

Returns the number of rows affected by the last INSERT, UPDATE, REPLACE or DELETE query.

For SELECT statements mysqli_affected_rows works like mysqli_num_rows.

Parameters

link

Procedural style only: A link identifier returned by mysqli_connect or mysqli_init

Return Values

An integer greater than zero indicates the number of rows affected or retrieved. Zero indicates that no records where updated for an UPDATE statement, no rows matched the WHERE clause in the query or that no query has yet been executed. -1 indicates that the query returned an error.Note

If the number of affected rows is greater than maximal int value, the number of affected rows will be returned as a string.

Examples

Example 20.99. $mysqli->affected_rows example

Object oriented style 

<?php
$mysqli = new mysqli('localhost', 'my_user', 'my_password', 'world');
/* check connection */
if (mysqli_connect_errno()) {
 printf('Connect failed: %s\n', mysqli_connect_error());
 exit();
}
/* Insert rows */
$mysqli->query('CREATE TABLE Language SELECT * from CountryLanguage');
printf('Affected rows (INSERT): %d\n', $mysqli->affected_rows);
$mysqli->query('ALTER TABLE Language ADD Status int default 0');
/* update rows */
$mysqli->query('UPDATE Language SET Status=1 WHERE Percentage > 50');
printf('Affected rows (UPDATE): %d\n', $mysqli->affected_rows);
/* delete rows */
$mysqli->query('DELETE FROM Language WHERE Percentage < 50');
printf('Affected rows (DELETE): %d\n', $mysqli->affected_rows);
/* select all rows */
$result = $mysqli->query('SELECT CountryCode FROM Language');
printf('Affected rows (SELECT): %d\n', $mysqli->affected_rows);
$result->close();
/* Delete table Language */
$mysqli->query('DROP TABLE Language');
/* close connection */
$mysqli->close();
?>

Procedural style 

<?php
$link = mysqli_connect('localhost', 'my_user', 'my_password', 'world');
if (!$link) {
 printf('Can't connect to localhost. Error: %s\n', mysqli_connect_error());
 exit();
}
/* Insert rows */
mysqli_query($link, 'CREATE TABLE Language SELECT * from CountryLanguage');
printf('Affected rows (INSERT): %d\n', mysqli_affected_rows($link));
mysqli_query($link, 'ALTER TABLE Language ADD Status int default 0');
/* update rows */
mysqli_query($link, 'UPDATE Language SET Status=1 WHERE Percentage > 50');
printf('Affected rows (UPDATE): %d\n', mysqli_affected_rows($link));
/* delete rows */
mysqli_query($link, 'DELETE FROM Language WHERE Percentage < 50');
printf('Affected rows (DELETE): %d\n', mysqli_affected_rows($link));
/* select all rows */
$result = mysqli_query($link, 'SELECT CountryCode FROM Language');
printf('Affected rows (SELECT): %d\n', mysqli_affected_rows($link));
mysqli_free_result($result);
/* Delete table Language */
mysqli_query($link, 'DROP TABLE Language');
/* close connection */
mysqli_close($link);
?>

The above examples will output: 

Affected rows (INSERT): 984
Affected rows (UPDATE): 168
Affected rows (DELETE): 815
Affected rows (SELECT): 169

See Also

mysqli_num_rows
mysqli_info
mysqli::autocommit, mysqli_autocommit

Description

Object oriented stylebool mysqli::autocommit(bool mode);

Procedural stylebool mysqli_autocommit(mysqli link,
bool mode);

Turns on or off auto-commit mode on queries for the database connection.

To determine the current state of autocommit use the SQL command SELECT @@autocommit.

Parameters

link

Procedural style only: A link identifier returned by mysqli_connect or mysqli_init

mode

Whether to turn on auto-commit or not.

Return Values

Returns TRUE on success or FALSE on failure.

Notes

Note

This function doesn't work with non transactional table types (like MyISAM or ISAM).

Examples

Example 20.100. mysqli::autocommit example

Object oriented style 

<?php
$mysqli = new mysqli('localhost', 'my_user', 'my_password', 'world');
if (mysqli_connect_errno()) {
 printf('Connect failed: %s\n', mysqli_connect_error());
 exit();
}
/* turn autocommit on */
$mysqli->autocommit(TRUE);
if ($result = $mysqli->query('SELECT @@autocommit')) {
 $row = $result->fetch_row();
 printf('Autocommit is %s\n', $row[0]);
 $result->free();
}
/* close connection */
$mysqli->close();
?>

Procedural style 

<?php
$link = mysqli_connect('localhost', 'my_user', 'my_password', 'world');
if (!$link) {
 printf('Can't connect to localhost. Error: %s\n', mysqli_connect_error());
 exit();
}
/* turn autocommit on */
mysqli_autocommit($link, TRUE);
if ($result = mysqli_query($link, 'SELECT @@autocommit')) {
 $row = mysqli_fetch_row($result);
 printf('Autocommit is %s\n', $row[0]);
 mysqli_free_result($result);
}
/* close connection */
mysqli_close($link);
?>

The above examples will output: 

Autocommit is 1

See Also

mysqli_commit
mysqli_rollback
mysqli::change_user, mysqli_change_user

Description

Object oriented stylebool mysqli::change_user(string user,
string password,
string database);

Procedural stylebool mysqli_change_user(mysqli link,
string user,
string password,
string database);

Changes the user of the specified database connection and sets the current database.

In order to successfully change users a valid username and password parameters must be provided and that user must have sufficient permissions to access the desired database. If for any reason authorization fails, the current user authentication will remain.

Parameters

link

Procedural style only: A link identifier returned by mysqli_connect or mysqli_init

user

The MariaDB user name.

password

The MariaDB password.

database

The database to change to.

If desired, the NULL value may be passed resulting in only changing the user and not selecting a database. To select a database in this case use the mysqli_select_db function.

Return Values

Returns TRUE on success or FALSE on failure.

Notes

Note

Using this command will always cause the current database connection to behave as if was a completely new database connection, regardless of if the operation was completed successfully. This reset includes performing a rollback on any active transactions, closing all temporary tables, and unlocking all locked tables.

Examples

Example 20.101. mysqli::change_user example

Object oriented style 

<?php
/* connect database test */
$mysqli = new mysqli('localhost', 'my_user', 'my_password', 'test');
/* check connection */
if (mysqli_connect_errno()) {
 printf('Connect failed: %s\n', mysqli_connect_error());
 exit();
}
/* Set Variable a */
$mysqli->query('SET @a:=1');
/* reset all and select a new database */
$mysqli->change_user('my_user', 'my_password', 'world');
if ($result = $mysqli->query('SELECT DATABASE()')) {
 $row = $result->fetch_row();
 printf('Default database: %s\n', $row[0]);
 $result->close();
}
if ($result = $mysqli->query('SELECT @a')) {
 $row = $result->fetch_row();
 if ($row[0] === NULL) {
 printf('Value of variable a is NULL\n');
 }
 $result->close();
}
/* close connection */
$mysqli->close();
?>

Procedural style 

<?php
/* connect database test */
$link = mysqli_connect('localhost', 'my_user', 'my_password', 'test');
/* check connection */
if (!$link) {
 printf('Connect failed: %s\n', mysqli_connect_error());
 exit();
}
/* Set Variable a */
mysqli_query($link, 'SET @a:=1');
/* reset all and select a new database */
mysqli_change_user($link, 'my_user', 'my_password', 'world');
if ($result = mysqli_query($link, 'SELECT DATABASE()')) {
 $row = mysqli_fetch_row($result);
 printf('Default database: %s\n', $row[0]);
 mysqli_free_result($result);
}
if ($result = mysqli_query($link, 'SELECT @a')) {
 $row = mysqli_fetch_row($result);
 if ($row[0] === NULL) {
 printf('Value of variable a is NULL\n');
 }
 mysqli_free_result($result);
}
/* close connection */
mysqli_close($link);
?>

The above examples will output: 

Default database: world Value of variable a is NULL

See Also

mysqli_connect
mysqli_select_db
mysqli::character_set_name, mysqli_character_set_name

Description

Object oriented stylestring mysqli::character_set_name();

Procedural stylestring mysqli_character_set_name(mysqli link);

Returns the current character set for the database connection.

Parameters

link

Procedural style only: A link identifier returned by mysqli_connect or mysqli_init

Return Values

The default character set for the current connection

Examples

Example 20.102. mysqli::character_set_name example

Object oriented style 

<?php
/* Open a connection */
$mysqli = new mysqli('localhost', 'my_user', 'my_password', 'world');
/* check connection */
if (mysqli_connect_errno()) {
 printf('Connect failed: %s\n', mysqli_connect_error());
 exit();
}
/* Print current character set */
$charset = $mysqli->character_set_name();
printf ('Current character set is %s\n', $charset);
$mysqli->close();
?>

Procedural style 

<?php
/* Open a connection */
$link = mysqli_connect('localhost', 'my_user', 'my_password', 'world');
/* check connection */
if (!$link) {
 printf('Connect failed: %s\n', mysqli_connect_error());
 exit();
}
/* Print current character set */
$charset = mysqli_character_set_name($link);
printf ('Current character set is %s\n',$charset);
/* close connection */
mysqli_close($link);
?>

The above examples will output: 

Current character set is latin1_swedish_ci

See Also

mysqli_client_encoding
mysqli_real_escape_string
mysqli::$client_info, mysqli_get_client_info

Description

Object oriented stylestring mysqli->client_info ;

Procedural stylestring mysqli_get_client_info(mysqli link);

Returns a string that represents the MariaDB client library version.

Return Values

A string that represents the MariaDB client library version

Examples

Example 20.103. mysqli_get_client_info

<?php
/* We don't need a connection to determine
 the version of mysql client library */
printf('Client library version: %s\n', mysqli_get_client_info());
?>

See Also

mysqli_get_client_version
mysqli_get_server_info
mysqli_get_server_version
mysqli::$client_version, mysqli_get_client_version

Description

Object oriented styleint mysqli->client_version ;

Procedural styleint mysqli_get_client_version(mysqli link);

Returns client version number as an integer.

Return Values

A number that represents the MariaDB client library version in format: main_version*10000 + minor_version *100 + sub_version. For example, 4.1.0 is returned as 40100.

This is useful to quickly determine the version of the client library to know if some capability exists.

Examples

Example 20.104. mysqli_get_client_version

<?php
/* We don't need a connection to determine
 the version of mysql client library */
printf('Client library version: %d\n', mysqli_get_client_version());
?>

See Also

mysqli_get_client_info
mysqli_get_server_info
mysqli_get_server_version
mysqli::close, mysqli_close

Description

Object oriented stylebool mysqli::close();

Procedural stylebool mysqli_close(mysqli link);

Closes a previously opened database connection.

Parameters

link

Procedural style only: A link identifier returned by mysqli_connect or mysqli_init

Return Values

Returns TRUE on success or FALSE on failure.

Examples

See mysqli_connect.

See Also

mysqli_connect
mysqli_init
mysqli_real_connect
mysqli::commit, mysqli_commit

Description

Object oriented stylebool mysqli::commit();

Procedural stylebool mysqli_commit(mysqli link);

Commits the current transaction for the database connection.

Parameters

link

Procedural style only: A link identifier returned by mysqli_connect or mysqli_init

Return Values

Returns TRUE on success or FALSE on failure.

Examples

Example 20.105. mysqli::commit example

Object oriented style 

<?php
$mysqli = new mysqli('localhost', 'my_user', 'my_password', 'world');
/* check connection */
if (mysqli_connect_errno()) {
 printf('Connect failed: %s\n', mysqli_connect_error());
 exit();
}
$mysqli->query('CREATE TABLE Language LIKE CountryLanguage');
/* set autocommit to off */
$mysqli->autocommit(FALSE);
/* Insert some values */
$mysqli->query('INSERT INTO Language VALUES ('DEU', 'Bavarian', 'F', 11.2)');
$mysqli->query('INSERT INTO Language VALUES ('DEU', 'Swabian', 'F', 9.4)');
/* commit transaction */
$mysqli->commit();
/* drop table */
$mysqli->query('DROP TABLE Language');
/* close connection */
$mysqli->close();
?>

Procedural style 

<?php
$link = mysqli_connect('localhost', 'my_user', 'my_password', 'test');
/* check connection */
if (!$link) {
 printf('Connect failed: %s\n', mysqli_connect_error());
 exit();
}
/* set autocommit to off */
mysqli_autocommit($link, FALSE);
mysqli_query($link, 'CREATE TABLE Language LIKE CountryLanguage');
/* Insert some values */
mysqli_query($link, 'INSERT INTO Language VALUES ('DEU', 'Bavarian', 'F', 11.2)');
mysqli_query($link, 'INSERT INTO Language VALUES ('DEU', 'Swabian', 'F', 9.4)');
/* commit transaction */
mysqli_commit($link);
/* close connection */
mysqli_close($link);
?>

See Also

mysqli_autocommit
mysqli_rollback
mysqli::$connect_errno, mysqli_connect_errno

Description

Object oriented stylestring mysqli->connect_errno ;

Procedural styleint mysqli_connect_errno();

Returns the last error code number from the last call to mysqli_connect.Note

Client error message numbers are listed in the MariaDB errmsg.h header file, server error message numbers are listed in mysqld_error.h. In the MariaDB source distribution you can find a complete list of error messages and error numbers in the file Docs/mysqld_error.txt.

Return Values

An error code value for the last call to mysqli_connect, if it failed. zero means no error occurred.

Examples

Example 20.106. $mysqli->connect_errno example

Object oriented style 

<?php
$mysqli = @new mysqli('localhost', 'fake_user', 'my_password', 'my_db');
if ($mysqli->connect_errno) {
 die('Connect Error: ' . $mysqli->connect_errno);
}
?>

Procedural style 

<?php
$link = @mysqli_connect('localhost', 'fake_user', 'my_password', 'my_db');
if (!$link) {
 die('Connect Error: ' . mysqli_connect_errno());
}
?>

The above examples will output: 

Connect Error: 1045

See Also

mysqli_connect
mysqli_connect_error
mysqli_errno
mysqli_error
mysqli_sqlstate
mysqli::$connect_error, mysqli_connect_error

Description

Object oriented stylestring mysqli->connect_error ;

Procedural stylestring mysqli_connect_error();

Returns the last error message string from the last call to mysqli_connect.

Return Values

A string that describes the error. NULL is returned if no error occurred.

Examples

Example 20.107. $mysqli->connect_error example

Object oriented style 

<?php
$mysqli = @new mysqli('localhost', 'fake_user', 'my_password', 'my_db');
// Works as of PHP 5.2.9 and 5.3.0.
if ($mysqli->connect_error) {
 die('Connect Error: ' . $mysqli->connect_error);
}
?>

Procedural style 

<?php
$link = @mysqli_connect('localhost', 'fake_user', 'my_password', 'my_db');
if (!$link) {
 die('Connect Error: ' . mysqli_connect_error());
}
?>

The above examples will output: 

Connect Error: Access denied for user 'fake_user'@'localhost' (using password: YES)

Notes

Warning

The mysqli->connect_error property only works properly as of PHP versions 5.2.9 and 5.3.0. Use the mysqli_connect_error function if compatibility with earlier PHP versions is required.

See Also

mysqli_connect
mysqli_connect_errno
mysqli_errno
mysqli_error
mysqli_sqlstate
mysqli::__construct, mysqli_connect

Description

Object oriented stylemysqli::__construct(string host= =ini_get('mysqli.default_host'),
string username= =ini_get('mysqli.default_user'),
string passwd= =ini_get('mysqli.default_pw'),
string dbname= ='',
int port= =ini_get('mysqli.default_port'),
string socket= =ini_get('mysqli.default_socket'));

Procedural stylemysqli mysqli_connect(string host= =ini_get('mysqli.default_host'),
string username= =ini_get('mysqli.default_user'),
string passwd= =ini_get('mysqli.default_pw'),
string dbname= ='',
int port= =ini_get('mysqli.default_port'),
string socket= =ini_get('mysqli.default_socket'));

Opens a connection to the MariaDB Server running on.

Parameters

host

Can be either a host name or an IP address. Passing the NULL value or the string 'localhost' to this parameter, the local host is assumed. When possible, pipes will be used instead of the TCP/IP protocol.

Prepending host by p: opens a persistent connection. mysqli_change_user is automatically called on connections opened from the connection pool.

username

The MariaDB user name.

passwd

If not provided or NULL , the MariaDB server will attempt to authenticate the user against those user records which have no password only. This allows one username to be used with different permissions (depending on if a password as provided or not).

dbname

If provided will specify the default database to be used when performing queries.

port

Specifies the port number to attempt to connect to the MariaDB server.

socket

Specifies the socket or named pipe that should be used.Note

Specifying the socket parameter will not explicitly determine the type of connection to be used when connecting to the MariaDB server. How the connection is made to the MariaDB database is determined by the host parameter.

Return Values

Returns an object which represents the connection to a MariaDB Server.

Changelog

Version Description
5.3.0 Added the ability of persistent connections.

Examples

Example 20.108. mysqli::__construct example

Object oriented style 

<?php
$mysqli = new mysqli('localhost', 'my_user', 'my_password', 'my_db');
/*
 * This is the 'official' OO way to do it,
 * BUT $connect_error was broken until PHP 5.2.9 and 5.3.0.
 */
if ($mysqli->connect_error) {
 die('Connect Error (' . $mysqli->connect_errno . ') '
 . $mysqli->connect_error);
}
/*
 * Use this instead of $connect_error if you need to ensure
 * compatibility with PHP versions prior to 5.2.9 and 5.3.0.
 */
if (mysqli_connect_error()) {
 die('Connect Error (' . mysqli_connect_errno() . ') '
 . mysqli_connect_error());
}
echo 'Success... ' . $mysqli->host_info . '\n';
$mysqli->close();
?>

Object oriented style when extending mysqli class 

<?php class foo_mysqli extends mysqli {
 public function __construct($host, $user, $pass, $db) {
 parent::__construct($host, $user, $pass, $db);
 if (mysqli_connect_error()) {
 die('Connect Error (' . mysqli_connect_errno() . ') '
 . mysqli_connect_error());
 }
 }
}
$db = new foo_mysqli('localhost', 'my_user', 'my_password', 'my_db');
echo 'Success... ' . $db->host_info . '\n';
$db->close();
?>

Procedural style 

<?php
$link = mysqli_connect('localhost', 'my_user', 'my_password', 'my_db');
if (!$link) {
 die('Connect Error (' . mysqli_connect_errno() . ') '
 . mysqli_connect_error());
}
echo 'Success... ' . mysqli_get_host_info($link) . '\n';
mysqli_close($link);
?>

The above examples will output: 

Success... MariaDB host info: localhost via TCP/IP

Notes

Note

MySQLnd always assumes the server default charset. This charset is sent during connection hand-shake/authentication, which mysqlnd will use.

Libmysql uses the default charset set in the my.cnf or by an explicit call to mysqli_options prior to calling mysqli_real_connect, but after mysqli_init.Note

OO syntax only: If a connection fails an object is still returned. To check if the connection failed then use either the mysqli_connect_error function or the mysqli->connect_error property as in the preceding examples.Note

If it is necessary to set options, such as the connection timeout, mysqli_real_connect must be used instead.Note

Calling the constructor with no parameters is the same as calling mysqli_init.Note

Error 'Can't create TCP/IP socket (10106)' usually means that the variables_order configure directive doesn't contain character E. On Windows, if the environment is not copied the SYSTEMROOT environment variable won't be available and PHP will have problems loading Winsock.

See Also

mysqli_real_connect
mysqli_options
mysqli_connect_errno
mysqli_connect_error
mysqli_close
mysqli::debug, mysqli_debug

Description

Object oriented stylebool mysqli::debug(string message);

Procedural stylebool mysqli_debug(string message);

Performs debugging operations using the Fred Fish debugging library.

Parameters

message

A string representing the debugging operation to perform

Return Values

Returns TRUE .

Notes

Note

To use the mysqli_debug function you must compile the MariaDB client library to support debugging.

Examples

Example 20.109. Generating a Trace File

<?php
/* Create a trace file in '/tmp/client.trace' on the local (client) machine: */
mysqli_debug('d:t:o,/tmp/client.trace');
?>

See Also

mysqli_dump_debug_info
mysqli_report
mysqli::disable_reads_from_master, mysqli_disable_reads_from_master

Description

Object oriented stylevoid mysqli::disable_reads_from_master();

Procedural stylebool mysqli_disable_reads_from_master(mysqli link); Warning

This function is currently not documented; only its argument list is available.Warning

This function has been DEPRECATED and REMOVED as of PHP 5.3.0.

mysqli::dump_debug_info, mysqli_dump_debug_info

Description

Object oriented stylebool mysqli::dump_debug_info();

Procedural stylebool mysqli_dump_debug_info(mysqli link);

This function is designed to be executed by an user with the SUPER privilege and is used to dump debugging information into the log for the MariaDB Server relating to the connection.

Parameters

link

Procedural style only: A link identifier returned by mysqli_connect or mysqli_init

Return Values

Returns TRUE on success or FALSE on failure.

See Also

mysqli_debug
mysqli::$errno, mysqli_errno

Description

Object oriented styleint mysqli->errno ;

Procedural styleint mysqli_errno(mysqli link);

Returns the last error code for the most recent MySQLi function call that can succeed or fail.

Client error message numbers are listed in the MariaDB errmsg.h header file, server error message numbers are listed in mysqld_error.h. In the MariaDB source distribution you can find a complete list of error messages and error numbers in the file Docs/mysqld_error.txt.

Parameters

link

Procedural style only: A link identifier returned by mysqli_connect or mysqli_init

Return Values

An error code value for the last call, if it failed. zero means no error occurred.

Examples

Example 20.110. $mysqli->errno example

Object oriented style 

<?php
$mysqli = new mysqli('localhost', 'my_user', 'my_password', 'world');
/* check connection */
if (mysqli_connect_errno()) {
 printf('Connect failed: %s\n', mysqli_connect_error());
 exit();
}
if (!$mysqli->query('SET a=1')) {
 printf('Errorcode: %d\n', $mysqli->errno);
}
/* close connection */
$mysqli->close();
?>

Procedural style 

<?php
$link = mysqli_connect('localhost', 'my_user', 'my_password', 'world');
/* check connection */
if (mysqli_connect_errno()) {
 printf('Connect failed: %s\n', mysqli_connect_error());
 exit();
}
if (!mysqli_query($link, 'SET a=1')) {
 printf('Errorcode: %d\n', mysqli_errno($link));
}
/* close connection */
mysqli_close($link);
?>

The above examples will output: 

Errorcode: 1193

See Also

mysqli_connect_errno
mysqli_connect_error
mysqli_error
mysqli_sqlstate
mysqli::$error_list, mysqli_error_list

Description

Object oriented stylearray mysqli->error_list ;

Procedural stylearray mysqli_error_list(mysqli link);

Returns a array of errors for the most recent MySQLi function call that can succeed or fail.

Parameters

link

Procedural style only: A link identifier returned by mysqli_connect or mysqli_init

Return Values

A list of errors, each as an associative array containing the errno, error, and sqlstate.

Examples

Example 20.111. $mysqli->error_list example

Object oriented style 

<?php
$mysqli = new mysqli('localhost', 'nobody', '');
/* check connection */
if (mysqli_connect_errno()) {
 printf('Connect failed: %s\n', mysqli_connect_error());
 exit();
}
if (!$mysqli->query('SET a=1')) {
 print_r($mysqli->error_list);
}
/* close connection */
$mysqli->close();
?>

Procedural style 

<?php
$link = mysqli_connect('localhost', 'my_user', 'my_password', 'world');
/* check connection */
if (mysqli_connect_errno()) {
 printf('Connect failed: %s\n', mysqli_connect_error());
 exit();
}
if (!mysqli_query($link, 'SET a=1')) {
 print_r(mysqli_error_list($link));
}
/* close connection */
mysqli_close($link);
?>

The above examples will output: 

Array
(
 [0] => Array
 (
 [errno] => 1193
 [sqlstate] => HY000
 [error] => Unknown system variable 'a'
 )
)

See Also

mysqli_connect_errno
mysqli_connect_error
mysqli_error
mysqli_sqlstate
mysqli::$error, mysqli_error

Description

Object oriented stylestring mysqli->error ;

Procedural stylestring mysqli_error(mysqli link);

Returns the last error message for the most recent MySQLi function call that can succeed or fail.

Parameters

link

Procedural style only: A link identifier returned by mysqli_connect or mysqli_init

Return Values

A string that describes the error. An empty string if no error occurred.

Examples

Example 20.112. $mysqli->error example

Object oriented style 

<?php
$mysqli = new mysqli('localhost', 'my_user', 'my_password', 'world');
/* check connection */
if (mysqli_connect_errno()) {
 printf('Connect failed: %s\n', mysqli_connect_error());
 exit();
}
if (!$mysqli->query('SET a=1')) {
 printf('Errormessage: %s\n', $mysqli->error);
}
/* close connection */
$mysqli->close();
?>

Procedural style 

<?php
$link = mysqli_connect('localhost', 'my_user', 'my_password', 'world');
/* check connection */
if (mysqli_connect_errno()) {
 printf('Connect failed: %s\n', mysqli_connect_error());
 exit();
}
if (!mysqli_query($link, 'SET a=1')) {
 printf('Errormessage: %s\n', mysqli_error($link));
}
/* close connection */
mysqli_close($link);
?>

The above examples will output: 

Errormessage: Unknown system variable 'a'

See Also

mysqli_connect_errno
mysqli_connect_error
mysqli_errno
mysqli_sqlstate
mysqli::$field_count, mysqli_field_count

Description

Object oriented styleint mysqli->field_count ;

Procedural styleint mysqli_field_count(mysqli link);

Returns the number of columns for the most recent query on the connection represented by the link parameter. This function can be useful when using the mysqli_store_result function to determine if the query should have produced a non-empty result set or not without knowing the nature of the query.

Parameters

link

Procedural style only: A link identifier returned by mysqli_connect or mysqli_init

Return Values

An integer representing the number of fields in a result set.

Examples

Example 20.113. $mysqli->field_count example

Object oriented style 

<?php
$mysqli = new mysqli('localhost', 'my_user', 'my_password', 'test');
$mysqli->query( 'DROP TABLE IF EXISTS friends');
$mysqli->query( 'CREATE TABLE friends (id int, name varchar(20))');
$mysqli->query( 'INSERT INTO friends VALUES (1,'Hartmut'), (2, 'Ulf')');
$mysqli->real_query('SELECT * FROM friends');
if ($mysqli->field_count) {
 /* this was a select/show or describe query */
 $result = $mysqli->store_result();
 /* process resultset */
 $row = $result->fetch_row();
 /* free resultset */
 $result->close();
}
/* close connection */
$mysqli->close();
?>

Procedural style 

<?php
$link = mysqli_connect('localhost', 'my_user', 'my_password', 'test');
mysqli_query($link, 'DROP TABLE IF EXISTS friends');
mysqli_query($link, 'CREATE TABLE friends (id int, name varchar(20))');
mysqli_query($link, 'INSERT INTO friends VALUES (1,'Hartmut'), (2, 'Ulf')');
mysqli_real_query($link, 'SELECT * FROM friends');
if (mysqli_field_count($link)) {
 /* this was a select/show or describe query */
 $result = mysqli_store_result($link);
 /* process resultset */
 $row = mysqli_fetch_row($result);
 /* free resultset */
 mysqli_free_result($result);
}
/* close connection */
mysqli_close($link);
?>
mysqli::get_charset, mysqli_get_charset

Description

Object oriented styleobject mysqli::get_charset();

Procedural styleobject mysqli_get_charset(mysqli link);

Returns a character set object providing several properties of the current active character set.

Parameters

link

Procedural style only: A link identifier returned by mysqli_connect or mysqli_init

Return Values

The function returns a character set object with the following properties:

charset

Character set name

collation

Collation name

dir

Directory the charset description was fetched from (?) or '' for built-in character sets

min_length

Minimum character length in bytes

max_length

Maximum character length in bytes

number

Internal character set number

state

Character set status (?)

Examples

Example 20.114. mysqli::get_charset example

Object oriented style 

<?php
 $db = mysqli_init();
 $db->real_connect('localhost','root','','test');
 var_dump($db->get_charset());
?>

Procedural style 

<?php
 $db = mysqli_init();
 mysqli_real_connect($db, 'localhost','root','','test');
 var_dump($db->get_charset());
?>

The above examples will output: 

object(stdClass)#2 (7) {
 ['charset']=>
 string(6) 'latin1'
 ['collation']=>
 string(17) 'latin1_swedish_ci'
 ['dir']=>
 string(0) ''
 ['min_length']=>
 int(1)
 ['max_length']=>
 int(1)
 ['number']=>
 int(8)
 ['state']=>
 int(801)
}

See Also

mysqli_character_set_name
mysqli_set_charset
mysqli::get_client_info, mysqli_get_client_info

Description

Object oriented stylestring mysqli::get_client_info();

Procedural stylestring mysqli_get_client_info(mysqli link);

Returns a string that represents the MariaDB client library version.

Return Values

A string that represents the MariaDB client library version

Examples

Example 20.115. mysqli_get_client_info

<?php
/* We don't need a connection to determine
 the version of mysql client library */
printf('Client library version: %s\n', mysqli_get_client_info());
?>

See Also

mysqli_get_client_version
mysqli_get_server_info
mysqli_get_server_version
mysqli_get_client_stats

Description

array mysqli_get_client_stats();

Returns client per-process statistics. Available only with mysqlnd.

Parameters

Return Values

Returns an array with client stats if success, FALSE otherwise.

Examples

Example 20.116. A mysqli_get_client_stats example 

<?php
$link = mysqli_connect();
print_r(mysqli_get_client_stats());
?>

The above example will output something similar to: 

Array
(
 [bytes_sent] => 43
 [bytes_received] => 80
 [packets_sent] => 1
 [packets_received] => 2
 [protocol_overhead_in] => 8
 [protocol_overhead_out] => 4
 [bytes_received_ok_packet] => 11
 [bytes_received_eof_packet] => 0
 [bytes_received_rset_header_packet] => 0
 [bytes_received_rset_field_meta_packet] => 0
 [bytes_received_rset_row_packet] => 0
 [bytes_received_prepare_response_packet] => 0
 [bytes_received_change_user_packet] => 0
 [packets_sent_command] => 0
 [packets_received_ok] => 1
 [packets_received_eof] => 0
 [packets_received_rset_header] => 0
 [packets_received_rset_field_meta] => 0
 [packets_received_rset_row] => 0
 [packets_received_prepare_response] => 0
 [packets_received_change_user] => 0
 [result_set_queries] => 0
 [non_result_set_queries] => 0
 [no_index_used] => 0
 [bad_index_used] => 0
 [slow_queries] => 0
 [buffered_sets] => 0
 [unbuffered_sets] => 0
 [ps_buffered_sets] => 0
 [ps_unbuffered_sets] => 0
 [flushed_normal_sets] => 0
 [flushed_ps_sets] => 0
 [ps_prepared_never_executed] => 0
 [ps_prepared_once_executed] => 0
 [rows_fetched_from_server_normal] => 0
 [rows_fetched_from_server_ps] => 0
 [rows_buffered_from_client_normal] => 0
 [rows_buffered_from_client_ps] => 0
 [rows_fetched_from_client_normal_buffered] => 0
 [rows_fetched_from_client_normal_unbuffered] => 0
 [rows_fetched_from_client_ps_buffered] => 0
 [rows_fetched_from_client_ps_unbuffered] => 0
 [rows_fetched_from_client_ps_cursor] => 0
 [rows_skipped_normal] => 0
 [rows_skipped_ps] => 0
 [copy_on_write_saved] => 0
 [copy_on_write_performed] => 0
 [command_buffer_too_small] => 0
 [connect_success] => 1
 [connect_failure] => 0
 [connection_reused] => 0
 [reconnect] => 0
 [pconnect_success] => 0
 [active_connections] => 1
 [active_persistent_connections] => 0
 [explicit_close] => 0
 [implicit_close] => 0
 [disconnect_close] => 0
 [in_middle_of_command_close] => 0
 [explicit_free_result] => 0
 [implicit_free_result] => 0
 [explicit_stmt_close] => 0
 [implicit_stmt_close] => 0
 [mem_emalloc_count] => 0
 [mem_emalloc_ammount] => 0
 [mem_ecalloc_count] => 0
 [mem_ecalloc_ammount] => 0
 [mem_erealloc_count] => 0
 [mem_erealloc_ammount] => 0
 [mem_efree_count] => 0
 [mem_malloc_count] => 0
 [mem_malloc_ammount] => 0
 [mem_calloc_count] => 0
 [mem_calloc_ammount] => 0
 [mem_realloc_count] => 0
 [mem_realloc_ammount] => 0
 [mem_free_count] => 0
 [proto_text_fetched_null] => 0
 [proto_text_fetched_bit] => 0
 [proto_text_fetched_tinyint] => 0
 [proto_text_fetched_short] => 0
 [proto_text_fetched_int24] => 0
 [proto_text_fetched_int] => 0
 [proto_text_fetched_bigint] => 0
 [proto_text_fetched_decimal] => 0
 [proto_text_fetched_float] => 0
 [proto_text_fetched_double] => 0
 [proto_text_fetched_date] => 0
 [proto_text_fetched_year] => 0
 [proto_text_fetched_time] => 0
 [proto_text_fetched_datetime] => 0
 [proto_text_fetched_timestamp] => 0
 [proto_text_fetched_string] => 0
 [proto_text_fetched_blob] => 0
 [proto_text_fetched_enum] => 0
 [proto_text_fetched_set] => 0
 [proto_text_fetched_geometry] => 0
 [proto_text_fetched_other] => 0
 [proto_binary_fetched_null] => 0
 [proto_binary_fetched_bit] => 0
 [proto_binary_fetched_tinyint] => 0
 [proto_binary_fetched_short] => 0
 [proto_binary_fetched_int24] => 0
 [proto_binary_fetched_int] => 0
 [proto_binary_fetched_bigint] => 0
 [proto_binary_fetched_decimal] => 0
 [proto_binary_fetched_float] => 0
 [proto_binary_fetched_double] => 0
 [proto_binary_fetched_date] => 0
 [proto_binary_fetched_year] => 0
 [proto_binary_fetched_time] => 0
 [proto_binary_fetched_datetime] => 0
 [proto_binary_fetched_timestamp] => 0
 [proto_binary_fetched_string] => 0
 [proto_binary_fetched_blob] => 0
 [proto_binary_fetched_enum] => 0
 [proto_binary_fetched_set] => 0
 [proto_binary_fetched_geometry] => 0
 [proto_binary_fetched_other] => 0
)

See Also

Stats description
mysqli::$client_version, mysqli_get_client_version

Description

Object oriented styleint mysqli->client_version ;

Procedural styleint mysqli_get_client_version(mysqli link);

Returns client version number as an integer.

Return Values

A number that represents the MariaDB client library version in format: main_version*10000 + minor_version *100 + sub_version. For example, 4.1.0 is returned as 40100.

This is useful to quickly determine the version of the client library to know if some capability exits.

Examples

Example 20.117. mysqli_get_client_version

<?php
/* We don't need a connection to determine
 the version of mysql client library */
printf('Client library version: %d\n', mysqli_get_client_version());
?>

See Also

mysqli_get_client_info
mysqli_get_server_info
mysqli_get_server_version
mysqli::get_connection_stats, mysqli_get_connection_stats

Description

Object oriented stylebool mysqli::get_connection_stats();

Procedural stylearray mysqli_get_connection_stats(mysqli link);

Returns statistics about the client connection. Available only with mysqlnd.

Parameters

link

Procedural style only: A link identifier returned by mysqli_connect or mysqli_init

Return Values

Returns an array with connection stats if success, FALSE otherwise.

Examples

Example 20.118. A mysqli_get_connection_stats example 

<?php
$link = mysqli_connect();
print_r(mysqli_get_connection_stats($link));
?>

The above example will output something similar to: 

Array
(
 [bytes_sent] => 43
 [bytes_received] => 80
 [packets_sent] => 1
 [packets_received] => 2
 [protocol_overhead_in] => 8
 [protocol_overhead_out] => 4
 [bytes_received_ok_packet] => 11
 [bytes_received_eof_packet] => 0
 [bytes_received_rset_header_packet] => 0
 [bytes_received_rset_field_meta_packet] => 0
 [bytes_received_rset_row_packet] => 0
 [bytes_received_prepare_response_packet] => 0
 [bytes_received_change_user_packet] => 0
 [packets_sent_command] => 0
 [packets_received_ok] => 1
 [packets_received_eof] => 0
 [packets_received_rset_header] => 0
 [packets_received_rset_field_meta] => 0
 [packets_received_rset_row] => 0
 [packets_received_prepare_response] => 0
 [packets_received_change_user] => 0
 [result_set_queries] => 0
 [non_result_set_queries] => 0
 [no_index_used] => 0
 [bad_index_used] => 0
 [slow_queries] => 0
 [buffered_sets] => 0
 [unbuffered_sets] => 0
 [ps_buffered_sets] => 0
 [ps_unbuffered_sets] => 0
 [flushed_normal_sets] => 0
 [flushed_ps_sets] => 0
 [ps_prepared_never_executed] => 0
 [ps_prepared_once_executed] => 0
 [rows_fetched_from_server_normal] => 0
 [rows_fetched_from_server_ps] => 0
 [rows_buffered_from_client_normal] => 0
 [rows_buffered_from_client_ps] => 0
 [rows_fetched_from_client_normal_buffered] => 0
 [rows_fetched_from_client_normal_unbuffered] => 0
 [rows_fetched_from_client_ps_buffered] => 0
 [rows_fetched_from_client_ps_unbuffered] => 0
 [rows_fetched_from_client_ps_cursor] => 0
 [rows_skipped_normal] => 0
 [rows_skipped_ps] => 0
 [copy_on_write_saved] => 0
 [copy_on_write_performed] => 0
 [command_buffer_too_small] => 0
 [connect_success] => 1
 [connect_failure] => 0
 [connection_reused] => 0
 [reconnect] => 0
 [pconnect_success] => 0
 [active_connections] => 1
 [active_persistent_connections] => 0
 [explicit_close] => 0
 [implicit_close] => 0
 [disconnect_close] => 0
 [in_middle_of_command_close] => 0
 [explicit_free_result] => 0
 [implicit_free_result] => 0
 [explicit_stmt_close] => 0
 [implicit_stmt_close] => 0
 [mem_emalloc_count] => 0
 [mem_emalloc_ammount] => 0
 [mem_ecalloc_count] => 0
 [mem_ecalloc_ammount] => 0
 [mem_erealloc_count] => 0
 [mem_erealloc_ammount] => 0
 [mem_efree_count] => 0
 [mem_malloc_count] => 0
 [mem_malloc_ammount] => 0
 [mem_calloc_count] => 0
 [mem_calloc_ammount] => 0
 [mem_realloc_count] => 0
 [mem_realloc_ammount] => 0
 [mem_free_count] => 0
 [proto_text_fetched_null] => 0
 [proto_text_fetched_bit] => 0
 [proto_text_fetched_tinyint] => 0
 [proto_text_fetched_short] => 0
 [proto_text_fetched_int24] => 0
 [proto_text_fetched_int] => 0
 [proto_text_fetched_bigint] => 0
 [proto_text_fetched_decimal] => 0
 [proto_text_fetched_float] => 0
 [proto_text_fetched_double] => 0
 [proto_text_fetched_date] => 0
 [proto_text_fetched_year] => 0
 [proto_text_fetched_time] => 0
 [proto_text_fetched_datetime] => 0
 [proto_text_fetched_timestamp] => 0
 [proto_text_fetched_string] => 0
 [proto_text_fetched_blob] => 0
 [proto_text_fetched_enum] => 0
 [proto_text_fetched_set] => 0
 [proto_text_fetched_geometry] => 0
 [proto_text_fetched_other] => 0
 [proto_binary_fetched_null] => 0
 [proto_binary_fetched_bit] => 0
 [proto_binary_fetched_tinyint] => 0
 [proto_binary_fetched_short] => 0
 [proto_binary_fetched_int24] => 0
 [proto_binary_fetched_int] => 0
 [proto_binary_fetched_bigint] => 0
 [proto_binary_fetched_decimal] => 0
 [proto_binary_fetched_float] => 0
 [proto_binary_fetched_double] => 0
 [proto_binary_fetched_date] => 0
 [proto_binary_fetched_year] => 0
 [proto_binary_fetched_time] => 0
 [proto_binary_fetched_datetime] => 0
 [proto_binary_fetched_timestamp] => 0
 [proto_binary_fetched_string] => 0
 [proto_binary_fetched_blob] => 0
 [proto_binary_fetched_enum] => 0
 [proto_binary_fetched_set] => 0
 [proto_binary_fetched_geometry] => 0
 [proto_binary_fetched_other] => 0
)

See Also

Stats description
mysqli::$host_info, mysqli_get_host_info

Description

Object oriented stylestring mysqli->host_info ;

Procedural stylestring mysqli_get_host_info(mysqli link);

Returns a string describing the connection represented by the link parameter (including the server host name).

Parameters

link

Procedural style only: A link identifier returned by mysqli_connect or mysqli_init

Return Values

A character string representing the server hostname and the connection type.

Examples

Example 20.119. $mysqli->host_info example

Object oriented style 

<?php
$mysqli = new mysqli('localhost', 'my_user', 'my_password', 'world');
/* check connection */
if (mysqli_connect_errno()) {
 printf('Connect failed: %s\n', mysqli_connect_error());
 exit();
}
/* print host information */
printf('Host info: %s\n', $mysqli->host_info);
/* close connection */
$mysqli->close();
?>

Procedural style 

<?php
$link = mysqli_connect('localhost', 'my_user', 'my_password', 'world');
/* check connection */
if (mysqli_connect_errno()) {
 printf('Connect failed: %s\n', mysqli_connect_error());
 exit();
}
/* print host information */
printf('Host info: %s\n', mysqli_get_host_info($link));
/* close connection */
mysqli_close($link);
?>

The above examples will output: 

Host info: Localhost via UNIX socket

See Also

mysqli_get_proto_info
mysqli::$protocol_version, mysqli_get_proto_info

Description

Object oriented stylestring mysqli->protocol_version ;

Procedural styleint mysqli_get_proto_info(mysqli link);

Returns an integer representing the MariaDB protocol version used by the connection represented by the link parameter.

Parameters

link

Procedural style only: A link identifier returned by mysqli_connect or mysqli_init

Return Values

Returns an integer representing the protocol version.

Examples

Example 20.120. $mysqli->protocol_version example

Object oriented style 

<?php
$mysqli = new mysqli('localhost', 'my_user', 'my_password');
/* check connection */
if (mysqli_connect_errno()) {
 printf('Connect failed: %s\n', mysqli_connect_error());
 exit();
}
/* print protocol version */
printf('Protocol version: %d\n', $mysqli->protocol_version);
/* close connection */
$mysqli->close();
?>

Procedural style 

<?php
$link = mysqli_connect('localhost', 'my_user', 'my_password');
/* check connection */
if (mysqli_connect_errno()) {
 printf('Connect failed: %s\n', mysqli_connect_error());
 exit();
}
/* print protocol version */
printf('Protocol version: %d\n', mysqli_get_proto_info($link));
/* close connection */
mysqli_close($link);
?>

The above examples will output: 

Protocol version: 10

See Also

mysqli_get_host_info
mysqli::$server_info, mysqli_get_server_info

Description

Object oriented stylestring mysqli->server_info ;

Procedural stylestring mysqli_get_server_info(mysqli link);

Returns a string representing the version of the MariaDB server that the MySQLi extension is connected to.

Parameters

link

Procedural style only: A link identifier returned by mysqli_connect or mysqli_init

Return Values

A character string representing the server version.

Examples

Example 20.121. $mysqli->server_info example

Object oriented style 

<?php
$mysqli = new mysqli('localhost', 'my_user', 'my_password');
/* check connection */
if (mysqli_connect_errno()) {
 printf('Connect failed: %s\n', mysqli_connect_error());
 exit();
}
/* print server version */
printf('Server version: %s\n', $mysqli->server_info);
/* close connection */
$mysqli->close();
?>

Procedural style 

<?php
$link = mysqli_connect('localhost', 'my_user', 'my_password');
/* check connection */
if (mysqli_connect_errno()) {
 printf('Connect failed: %s\n', mysqli_connect_error());
 exit();
}
/* print server version */
printf('Server version: %s\n', mysqli_get_server_info($link));
/* close connection */
mysqli_close($link);
?>

The above examples will output: 

Server version: 4.1.2-alpha-debug

See Also

mysqli_get_client_info
mysqli_get_client_version
mysqli_get_server_version
mysqli::$server_version, mysqli_get_server_version

Description

Object oriented styleint mysqli->server_version ;

Procedural styleint mysqli_get_server_version(mysqli link);

The mysqli_get_server_version function returns the version of the server connected to (represented by the link parameter) as an integer.

Parameters

link

Procedural style only: A link identifier returned by mysqli_connect or mysqli_init

Return Values

An integer representing the server version.

The form of this version number is main_version * 10000 + minor_version * 100 + sub_version (i.e. version 4.1.0 is 40100).

Examples

Example 20.122. $mysqli->server_version example

Object oriented style 

<?php
$mysqli = new mysqli('localhost', 'my_user', 'my_password');
/* check connection */
if (mysqli_connect_errno()) {
 printf('Connect failed: %s\n', mysqli_connect_error());
 exit();
}
/* print server version */
printf('Server version: %d\n', $mysqli->server_version);
/* close connection */
$mysqli->close();
?>

Procedural style 

<?php
$link = mysqli_connect('localhost', 'my_user', 'my_password');
/* check connection */
if (mysqli_connect_errno()) {
 printf('Connect failed: %s\n', mysqli_connect_error());
 exit();
}
/* print server version */
printf('Server version: %d\n', mysqli_get_server_version($link));
/* close connection */
mysqli_close($link);
?>

The above examples will output: 

Server version: 40102

See Also

mysqli_get_client_info
mysqli_get_client_version
mysqli_get_server_info
mysqli::get_warnings, mysqli_get_warnings

Description

Object oriented stylemysqli_warning mysqli::get_warnings();

Procedural stylemysqli_warning mysqli_get_warnings(mysqli link); Warning

This function is currently not documented; only its argument list is available.

mysqli::$info, mysqli_info

Description

Object oriented stylestring mysqli->info ;

Procedural stylestring mysqli_info(mysqli link);

The mysqli_info function returns a string providing information about the last query executed. The nature of this string is provided below:

Table 20.14. Possible mysqli_info return values

Query type Example result string
INSERT INTO...SELECT... Records: 100 Duplicates: 0 Warnings: 0
INSERT INTO...VALUES (...),(...),(...) Records: 3 Duplicates: 0 Warnings: 0
LOAD DATA INFILE ... Records: 1 Deleted: 0 Skipped: 0 Warnings: 0
ALTER TABLE ... Records: 3 Duplicates: 0 Warnings: 0
UPDATE ... Rows matched: 40 Changed: 40 Warnings: 0
Note

Queries which do not fall into one of the preceding formats are not supported. In these situations, mysqli_info will return an empty string.

Parameters

link

Procedural style only: A link identifier returned by mysqli_connect or mysqli_init

Return Values

A character string representing additional information about the most recently executed query.

Examples

Example 20.123. $mysqli->info example

Object oriented style 

<?php
$mysqli = new mysqli('localhost', 'my_user', 'my_password', 'world');
/* check connection */
if (mysqli_connect_errno()) {
 printf('Connect failed: %s\n', mysqli_connect_error());
 exit();
}
$mysqli->query('CREATE TEMPORARY TABLE t1 LIKE City');
/* INSERT INTO .. SELECT */
$mysqli->query('INSERT INTO t1 SELECT * FROM City ORDER BY ID LIMIT 150');
printf('%s\n', $mysqli->info);
/* close connection */
$mysqli->close();
?>

Procedural style 

<?php
$link = mysqli_connect('localhost', 'my_user', 'my_password', 'world');
/* check connection */
if (mysqli_connect_errno()) {
 printf('Connect failed: %s\n', mysqli_connect_error());
 exit();
}
mysqli_query($link, 'CREATE TEMPORARY TABLE t1 LIKE City');
/* INSERT INTO .. SELECT */
mysqli_query($link, 'INSERT INTO t1 SELECT * FROM City ORDER BY ID LIMIT 150');
printf('%s\n', mysqli_info($link));
/* close connection */
mysqli_close($link);
?>

The above examples will output: 

Records: 150 Duplicates: 0 Warnings: 0

See Also

mysqli_affected_rows
mysqli_warning_count
mysqli_num_rows
mysqli::init, mysqli_init

Description

Object oriented stylemysqli mysqli::init();

Procedural stylemysqli mysqli_init();

Allocates or initializes a MYSQL object suitable for mysqli_options and mysqli_real_connect.Note

Any subsequent calls to any mysqli function (except mysqli_options) will fail until mysqli_real_connect was called.

Return Values

Returns an object.

Examples

See mysqli_real_connect.

See Also

mysqli_options
mysqli_close
mysqli_real_connect
mysqli_connect
mysqli::$insert_id, mysqli_insert_id

Description

Object oriented stylemixed mysqli->insert_id ;

Procedural stylemixed mysqli_insert_id(mysqli link);

The mysqli_insert_id function returns the ID generated by a query on a table with a column having the AUTO_INCREMENT attribute. If the last query wasn't an INSERT or UPDATE statement or if the modified table does not have a column with the AUTO_INCREMENT attribute, this function will return zero.Note

Performing an INSERT or UPDATE statement using the LAST_INSERT_ID() function will also modify the value returned by the mysqli_insert_id function.

Parameters

link

Procedural style only: A link identifier returned by mysqli_connect or mysqli_init

Return Values

The value of the AUTO_INCREMENT field that was updated by the previous query. Returns zero if there was no previous query on the connection or if the query did not update an AUTO_INCREMENT value.Note

If the number is greater than maximal int value, mysqli_insert_id will return a string.

Examples

Example 20.124. $mysqli->insert_id example

Object oriented style 

<?php
$mysqli = new mysqli('localhost', 'my_user', 'my_password', 'world');
/* check connection */
if (mysqli_connect_errno()) {
 printf('Connect failed: %s\n', mysqli_connect_error());
 exit();
}
$mysqli->query('CREATE TABLE myCity LIKE City');
$query = 'INSERT INTO myCity VALUES (NULL, 'Stuttgart', 'DEU', 'Stuttgart', 617000)';
$mysqli->query($query);
printf ('New Record has id %d.\n', $mysqli->insert_id);
/* drop table */
$mysqli->query('DROP TABLE myCity');
/* close connection */
$mysqli->close();
?>

Procedural style 

<?php
$link = mysqli_connect('localhost', 'my_user', 'my_password', 'world');
/* check connection */
if (mysqli_connect_errno()) {
 printf('Connect failed: %s\n', mysqli_connect_error());
 exit();
}
mysqli_query($link, 'CREATE TABLE myCity LIKE City');
$query = 'INSERT INTO myCity VALUES (NULL, 'Stuttgart', 'DEU', 'Stuttgart', 617000)';
mysqli_query($link, $query);
printf ('New Record has id %d.\n', mysqli_insert_id($link));
/* drop table */
mysqli_query($link, 'DROP TABLE myCity');
/* close connection */
mysqli_close($link);
?>

The above examples will output: 

New Record has id 1.
mysqli::kill, mysqli_kill

Description

Object oriented stylebool mysqli::kill(int processid);

Procedural stylebool mysqli_kill(mysqli link,
int processid);

This function is used to ask the server to kill a MariaDB thread specified by the processid parameter. This value must be retrieved by calling the mysqli_thread_id function.

To stop a running query you should use the SQL command KILL QUERY processid.

Parameters

link

Procedural style only: A link identifier returned by mysqli_connect or mysqli_init

Return Values

Returns TRUE on success or FALSE on failure.

Examples

Example 20.125. mysqli::kill example

Object oriented style 

<?php
$mysqli = new mysqli('localhost', 'my_user', 'my_password', 'world');
/* check connection */
if (mysqli_connect_errno()) {
 printf('Connect failed: %s\n', mysqli_connect_error());
 exit();
}
/* determine our thread id */
$thread_id = $mysqli->thread_id;
/* Kill connection */
$mysqli->kill($thread_id);
/* This should produce an error */
if (!$mysqli->query('CREATE TABLE myCity LIKE City')) {
 printf('Error: %s\n', $mysqli->error);
 exit;
}
/* close connection */
$mysqli->close();
?>

Procedural style 

<?php
$link = mysqli_connect('localhost', 'my_user', 'my_password', 'world');
/* check connection */
if (mysqli_connect_errno()) {
 printf('Connect failed: %s\n', mysqli_connect_error());
 exit();
}
/* determine our thread id */
$thread_id = mysqli_thread_id($link);
/* Kill connection */
mysqli_kill($link, $thread_id);
/* This should produce an error */
if (!mysqli_query($link, 'CREATE TABLE myCity LIKE City')) {
 printf('Error: %s\n', mysqli_error($link));
 exit;
}
/* close connection */
mysqli_close($link);
?>

The above examples will output: 

Error: MariaDB server has gone away

See Also

mysqli_thread_id
mysqli::more_results, mysqli_more_results

Description

Object oriented stylebool mysqli::more_results();

Procedural stylebool mysqli_more_results(mysqli link);

Indicates if one or more result sets are available from a previous call to mysqli_multi_query.

Parameters

link

Procedural style only: A link identifier returned by mysqli_connect or mysqli_init

Return Values

Returns TRUE on success or FALSE on failure.

Examples

See mysqli_multi_query.

See Also

mysqli_multi_query
mysqli_next_result
mysqli_store_result
mysqli_use_result
mysqli::multi_query, mysqli_multi_query

Description

Object oriented stylebool mysqli::multi_query(string query);

Procedural stylebool mysqli_multi_query(mysqli link,
string query);

Executes one or multiple queries which are concatenated by a semicolon.

To retrieve the resultset from the first query you can use mysqli_use_result or mysqli_store_result. All subsequent query results can be processed using mysqli_more_results and mysqli_next_result.

Parameters

link

Procedural style only: A link identifier returned by mysqli_connect or mysqli_init

query

The query, as a string.

Data inside the query should be properly escaped.

Return Values

Returns FALSE if the first statement failed. To retrieve subsequent errors from other statements you have to call mysqli_next_result first.

Examples

Example 20.126. mysqli::multi_query example

Object oriented style 

<?php
$mysqli = new mysqli('localhost', 'my_user', 'my_password', 'world');
/* check connection */
if (mysqli_connect_errno()) {
 printf('Connect failed: %s\n', mysqli_connect_error());
 exit();
}
$query = 'SELECT CURRENT_USER();';
$query .= 'SELECT Name FROM City ORDER BY ID LIMIT 20, 5';
/* execute multi query */
if ($mysqli->multi_query($query)) {
 do {
 /* store first result set */
 if ($result = $mysqli->store_result()) {
 while ($row = $result->fetch_row()) {
 printf('%s\n', $row[0]);
 }
 $result->free();
 }
 /* print divider */
 if ($mysqli->more_results()) {
 printf('-----------------\n');
 }
 } while ($mysqli->next_result());
}
/* close connection */
$mysqli->close();
?>

Procedural style 

<?php
$link = mysqli_connect('localhost', 'my_user', 'my_password', 'world');
/* check connection */
if (mysqli_connect_errno()) {
 printf('Connect failed: %s\n', mysqli_connect_error());
 exit();
}
$query = 'SELECT CURRENT_USER();';
$query .= 'SELECT Name FROM City ORDER BY ID LIMIT 20, 5';
/* execute multi query */
if (mysqli_multi_query($link, $query)) {
 do {
 /* store first result set */
 if ($result = mysqli_store_result($link)) {
 while ($row = mysqli_fetch_row($result)) {
 printf('%s\n', $row[0]);
 }
 mysqli_free_result($result);
 }
 /* print divider */
 if (mysqli_more_results($link)) {
 printf('-----------------\n');
 }
 } while (mysqli_next_result($link));
}
/* close connection */
mysqli_close($link);
?>

The above examples will output something similar to: 

my_user@localhost
-----------------
Amersfoort Maastricht Dordrecht Leiden Haarlemmermeer

See Also

mysqli_use_result
mysqli_store_result
mysqli_next_result
mysqli_more_results
mysqli::next_result, mysqli_next_result

Description

Object oriented stylebool mysqli::next_result();

Procedural stylebool mysqli_next_result(mysqli link);

Prepares next result set from a previous call to mysqli_multi_query which can be retrieved by mysqli_store_result or mysqli_use_result.

Parameters

link

Procedural style only: A link identifier returned by mysqli_connect or mysqli_init

Return Values

Returns TRUE on success or FALSE on failure.

Examples

See mysqli_multi_query.

See Also

mysqli_multi_query
mysqli_more_results
mysqli_store_result
mysqli_use_result
mysqli::options, mysqli_options

Description

Object oriented stylebool mysqli::options(int option,
mixed value);

Procedural stylebool mysqli_options(mysqli link,
int option,
mixed value);

Used to set extra connect options and affect behavior for a connection.

This function may be called multiple times to set several options.

mysqli-options should be called after mysqli_init and before mysqli_real_connect.

Parameters

link

Procedural style only: A link identifier returned by mysqli_connect or mysqli_init

option

The option that you want to set. It can be one of the following values:

Table 20.15. Valid options

Name Description
MYSQLI_OPT_CONNECT_TIMEOUT connection timeout in seconds (supported on Windows with TCP/IP since PHP 5.3.1)
MYSQLI_OPT_LOCAL_INFILE enable/disable use of LOAD LOCAL INFILE
MYSQLI_INIT_COMMAND command to execute after when connecting to MariaDB server
MYSQLI_READ_DEFAULT_FILE Read options from named option file instead of my.cnf
MYSQLI_READ_DEFAULT_GROUP Read options from the named group from my.cnf or the file specified with MYSQL_READ_DEFAULT_FILE .
value

The value for the option.

Return Values

Returns TRUE on success or FALSE on failure.

Examples

See mysqli_real_connect.

Notes

Note

MySQLnd always assumes the server default charset. This charset is sent during connection hand-shake/authentication, which mysqlnd will use.

Libmysql uses the default charset set in the my.cnf or by an explicit call to mysqli_options prior to calling mysqli_real_connect, but after mysqli_init.

See Also

mysqli_init
mysqli_real_connect
mysqli::ping, mysqli_ping

Description

Object oriented stylebool mysqli::ping();

Procedural stylebool mysqli_ping(mysqli link);

Checks whether the connection to the server is working. If it has gone down, and global option mysqli.reconnect is enabled an automatic reconnection is attempted.

This function can be used by clients that remain idle for a long while, to check whether the server has closed the connection and reconnect if necessary.

Parameters

link

Procedural style only: A link identifier returned by mysqli_connect or mysqli_init

Return Values

Returns TRUE on success or FALSE on failure.

Examples

Example 20.127. mysqli::ping example

Object oriented style 

<?php
$mysqli = new mysqli('localhost', 'my_user', 'my_password', 'world');
/* check connection */
if (mysqli_connect_errno()) {
 printf('Connect failed: %s\n', mysqli_connect_error());
 exit();
}
/* check if server is alive */
if ($mysqli->ping()) {
 printf ('Our connection is ok!\n');
} else {
 printf ('Error: %s\n', $mysqli->error);
}
/* close connection */
$mysqli->close();
?>

Procedural style 

<?php
$link = mysqli_connect('localhost', 'my_user', 'my_password', 'world');
/* check connection */
if (mysqli_connect_errno()) {
 printf('Connect failed: %s\n', mysqli_connect_error());
 exit();
}
/* check if server is alive */
if (mysqli_ping($link)) {
 printf ('Our connection is ok!\n');
} else {
 printf ('Error: %s\n', mysqli_error($link));
}
/* close connection */
mysqli_close($link);
?>

The above examples will output: 

Our connection is ok!
mysqli::poll, mysqli_poll

Description

Object oriented stylepublic int mysqli::poll(array read,
array error,
array reject,
int sec,
int usec);

Procedural styleint mysqli_poll(array read,
array error,
array reject,
int sec,
int usec); Warning

This function is currently not documented; only its argument list is available.

Poll connections. Available only with mysqlnd.

Parameters

read
error
reject
sec

Number of seconds to wait, must be non-negative.

usec

Number of microseconds to wait, must be non-negative.

Return Values

Returns number of ready connections in success, FALSE otherwise.

Examples

Example 20.128. A mysqli_poll example 

<?php
$link1 = mysqli_connect();
$link1->query('SELECT 'test'', MYSQLI_ASYNC);
$all_links = array($link1);
$processed = 0;
do {
 $links = $errors = $reject = array();
 foreach ($all_links as $link) {
 $links[] = $errors[] = $reject[] = $link;
 }
 if (!mysqli_poll($links, $errors, $reject, 1)) {
 continue;
 }
 foreach ($links as $link) {
 if ($result = $link->reap_async_query()) {
 print_r($result->fetch_row());
 mysqli_free_result($result);
 $processed++;
 }
 }
} while ($processed < count($all_links));
?>

The above example will output: 

Array
(
 [0] => test
)

See Also

mysqli_query
mysqli_reap_async_query
mysqli::prepare, mysqli_prepare

Description

Object oriented stylemysqli_stmt mysqli::prepare(string query);

Procedural stylemysqli_stmt mysqli_prepare(mysqli link,
string query);

Prepares the SQL query, and returns a statement handle to be used for further operations on the statement. The query must consist of a single SQL statement.

The parameter markers must be bound to application variables using mysqli_stmt_bind_param and/or mysqli_stmt_bind_result before executing the statement or fetching rows.

Parameters

link

Procedural style only: A link identifier returned by mysqli_connect or mysqli_init

query

The query, as a string.Note

You should not add a terminating semicolon or \g to the statement.

This parameter can include one or more parameter markers in the SQL statement by embedding question mark (?) characters at the appropriate positions.Note

The markers are legal only in certain places in SQL statements. For example, they are allowed in the VALUES() list of an INSERT statement (to specify column values for a row), or in a comparison with a column in a WHERE clause to specify a comparison value.

However, they are not allowed for identifiers (such as table or column names), in the select list that names the columns to be returned by a SELECT statement, or to specify both operands of a binary operator such as the = equal sign. The latter restriction is necessary because it would be impossible to determine the parameter type. It's not allowed to compare marker with NULL by ? IS NULL too. In general, parameters are legal only in Data Manipulation Language (DML) statements, and not in Data Definition Language (DDL) statements.

Return Values

mysqli_prepare returns a statement object or FALSE if an error occurred.

Examples

Example 20.129. mysqli::prepare example

Object oriented style 

<?php
$mysqli = new mysqli('localhost', 'my_user', 'my_password', 'world');
/* check connection */
if (mysqli_connect_errno()) {
 printf('Connect failed: %s\n', mysqli_connect_error());
 exit();
}
$city = 'Amersfoort';
/* create a prepared statement */
if ($stmt = $mysqli->prepare('SELECT District FROM City WHERE Name=?')) {
 /* bind parameters for markers */
 $stmt->bind_param('s', $city);
 /* execute query */
 $stmt->execute();
 /* bind result variables */
 $stmt->bind_result($district);
 /* fetch value */
 $stmt->fetch();
 printf('%s is in district %s\n', $city, $district);
 /* close statement */
 $stmt->close();
}
/* close connection */
$mysqli->close();
?>

Procedural style 

<?php
$link = mysqli_connect('localhost', 'my_user', 'my_password', 'world');
/* check connection */
if (mysqli_connect_errno()) {
 printf('Connect failed: %s\n', mysqli_connect_error());
 exit();
}
$city = 'Amersfoort';
/* create a prepared statement */
if ($stmt = mysqli_prepare($link, 'SELECT District FROM City WHERE Name=?')) {
 /* bind parameters for markers */
 mysqli_stmt_bind_param($stmt, 's', $city);
 /* execute query */
 mysqli_stmt_execute($stmt);
 /* bind result variables */
 mysqli_stmt_bind_result($stmt, $district);
 /* fetch value */
 mysqli_stmt_fetch($stmt);
 printf('%s is in district %s\n', $city, $district);
 /* close statement */
 mysqli_stmt_close($stmt);
}
/* close connection */
mysqli_close($link);
?>

The above examples will output: 

Amersfoort is in district Utrecht

See Also

mysqli_stmt_execute
mysqli_stmt_fetch
mysqli_stmt_bind_param
mysqli_stmt_bind_result
mysqli_stmt_close
mysqli::query, mysqli_query

Description

Object oriented stylemixed mysqli::query(string query,
int resultmode= =MYSQLI_STORE_RESULT);

Procedural stylemixed mysqli_query(mysqli link,
string query,
int resultmode= =MYSQLI_STORE_RESULT);

Performs a query against the database.

Functionally, using this function is identical to calling mysqli_real_query followed either by mysqli_use_result or mysqli_store_result.Note

In the case where you pass a statement to mysqli_query that is longer than max_allowed_packet of the server, the returned error codes are different depending on whether you are using MariaDB Native Driver (mysqlnd) or MariaDB Client Library (libmysql). The behavior is as follows:

Parameters

link

Procedural style only: A link identifier returned by mysqli_connect or mysqli_init

query

The query string.

Data inside the query should be properly escaped.

resultmode

Either the constant MYSQLI_USE_RESULT or MYSQLI_STORE_RESULT depending on the desired behavior. By default, MYSQLI_STORE_RESULT is used.

If you use MYSQLI_USE_RESULT all subsequent calls will return error Commands out of sync unless you call mysqli_free_result

With MYSQLI_ASYNC (available with mysqlnd), it is possible to perform query asynchronously. mysqli_poll is then used to get results from such queries.

Return Values

Returns FALSE on failure. For successful SELECT, SHOW, DESCRIBE or EXPLAIN queries mysqli_query will return a mysqli_result object. For other successful queries mysqli_query will return TRUE .

Changelog

Version Description
5.3.0 Added the ability of async queries.

Examples

Example 20.130. mysqli::query example

Object oriented style 

<?php
$mysqli = new mysqli('localhost', 'my_user', 'my_password', 'world');
/* check connection */
if ($mysqli->connect_errno) {
 printf('Connect failed: %s\n', $mysqli->connect_error);
 exit();
}
/* Create table doesn't return a resultset */
if ($mysqli->query('CREATE TEMPORARY TABLE myCity LIKE City') === TRUE) {
 printf('Table myCity successfully created.\n');
}
/* Select queries return a resultset */
if ($result = $mysqli->query('SELECT Name FROM City LIMIT 10')) {
 printf('Select returned %d rows.\n', $result->num_rows);
 /* free result set */
 $result->close();
}
/* If we have to retrieve large amount of data we use MYSQLI_USE_RESULT */
if ($result = $mysqli->query('SELECT * FROM City', MYSQLI_USE_RESULT)) {
 /* Note, that we can't execute any functions which interact with the
 server until result set was closed. All calls will return an
 'out of sync' error */
 if (!$mysqli->query('SET @a:='this will not work'')) {
 printf('Error: %s\n', $mysqli->error);
 }
 $result->close();
}
$mysqli->close();
?>

Procedural style 

<?php
$link = mysqli_connect('localhost', 'my_user', 'my_password', 'world');
/* check connection */
if (mysqli_connect_errno()) {
 printf('Connect failed: %s\n', mysqli_connect_error());
 exit();
}
/* Create table doesn't return a resultset */
if (mysqli_query($link, 'CREATE TEMPORARY TABLE myCity LIKE City') === TRUE) {
 printf('Table myCity successfully created.\n');
}
/* Select queries return a resultset */
if ($result = mysqli_query($link, 'SELECT Name FROM City LIMIT 10')) {
 printf('Select returned %d rows.\n', mysqli_num_rows($result));
 /* free result set */
 mysqli_free_result($result);
}
/* If we have to retrieve large amount of data we use MYSQLI_USE_RESULT */
if ($result = mysqli_query($link, 'SELECT * FROM City', MYSQLI_USE_RESULT)) {
 /* Note, that we can't execute any functions which interact with the
 server until result set was closed. All calls will return an
 'out of sync' error */
 if (!mysqli_query($link, 'SET @a:='this will not work'')) {
 printf('Error: %s\n', mysqli_error($link));
 }
 mysqli_free_result($result);
}
mysqli_close($link);
?>

The above examples will output: 

Table myCity successfully created.
Select returned 10 rows.
Error: Commands out of sync; You can't run this command now

See Also

mysqli_real_query
mysqli_multi_query
mysqli_free_result
mysqli::real_connect, mysqli_real_connect

Description

Object oriented stylebool mysqli::real_connect(string host,
string username,
string passwd,
string dbname,
int port,
string socket,
int flags);

Procedural stylebool mysqli_real_connect(mysqli link,
string host,
string username,
string passwd,
string dbname,
int port,
string socket,
int flags);

Establish a connection to a MariaDB database engine.

This function differs from mysqli_connect:

Parameters

link

Procedural style only: A link identifier returned by mysqli_connect or mysqli_init

host

Can be either a host name or an IP address. Passing the NULL value or the string 'localhost' to this parameter, the local host is assumed. When possible, pipes will be used instead of the TCP/IP protocol.

username

The MariaDB user name.

passwd

If provided or NULL , the MariaDB server will attempt to authenticate the user against those user records which have no password only. This allows one username to be used with different permissions (depending on if a password as provided or not).

dbname

If provided will specify the default database to be used when performing queries.

port

Specifies the port number to attempt to connect to the MariaDB server.

socket

Specifies the socket or named pipe that should be used.Note

Specifying the socket parameter will not explicitly determine the type of connection to be used when connecting to the MariaDB server. How the connection is made to the MariaDB database is determined by the host parameter.

flags

With the parameter flags you can set different connection options:

Table 20.16. Supported flags

Name Description
MYSQLI_CLIENT_COMPRESS Use compression protocol
MYSQLI_CLIENT_FOUND_ROWS return number of matched rows, not the number of affected rows
MYSQLI_CLIENT_IGNORE_SPACE Allow spaces after function names. Makes all function names reserved words.
MYSQLI_CLIENT_INTERACTIVE Allow interactive_timeout seconds (instead of wait_timeout seconds) of inactivity before closing the connection
MYSQLI_CLIENT_SSL Use SSL (encryption)
Note

For security reasons the MULTI_STATEMENT flag is not supported in PHP. If you want to execute multiple queries use the mysqli_multi_query function.

Return Values

Returns TRUE on success or FALSE on failure.

Examples

Example 20.131. mysqli::real_connect example

Object oriented style 

<?php
$mysqli = mysqli_init();
if (!$mysqli) {
 die('mysqli_init failed');
}
if (!$mysqli->options(MYSQLI_INIT_COMMAND, 'SET AUTOCOMMIT = 0')) {
 die('Setting MYSQLI_INIT_COMMAND failed');
}
if (!$mysqli->options(MYSQLI_OPT_CONNECT_TIMEOUT, 5)) {
 die('Setting MYSQLI_OPT_CONNECT_TIMEOUT failed');
}
if (!$mysqli->real_connect('localhost', 'my_user', 'my_password', 'my_db')) {
 die('Connect Error (' . mysqli_connect_errno() . ') '
 . mysqli_connect_error());
}
echo 'Success... ' . $mysqli->host_info . '\n';
$mysqli->close();
?>

Object oriented style when extending mysqli class 

<?php class foo_mysqli extends mysqli {
 public function __construct($host, $user, $pass, $db) {
 parent::init();
 if (!parent::options(MYSQLI_INIT_COMMAND, 'SET AUTOCOMMIT = 0')) {
 die('Setting MYSQLI_INIT_COMMAND failed');
 }
 if (!parent::options(MYSQLI_OPT_CONNECT_TIMEOUT, 5)) {
 die('Setting MYSQLI_OPT_CONNECT_TIMEOUT failed');
 }
 if (!parent::real_connect($host, $user, $pass, $db)) {
 die('Connect Error (' . mysqli_connect_errno() . ') '
 . mysqli_connect_error());
 }
 }
}
$db = new foo_mysqli('localhost', 'my_user', 'my_password', 'my_db');
echo 'Success... ' . $db->host_info . '\n';
$db->close();
?>

Procedural style 

<?php
$link = mysqli_init();
if (!$link) {
 die('mysqli_init failed');
}
if (!mysqli_options($link, MYSQLI_INIT_COMMAND, 'SET AUTOCOMMIT = 0')) {
 die('Setting MYSQLI_INIT_COMMAND failed');
}
if (!mysqli_options($link, MYSQLI_OPT_CONNECT_TIMEOUT, 5)) {
 die('Setting MYSQLI_OPT_CONNECT_TIMEOUT failed');
}
if (!mysqli_real_connect($link, 'localhost', 'my_user', 'my_password', 'my_db')) {
 die('Connect Error (' . mysqli_connect_errno() . ') '
 . mysqli_connect_error());
}
echo 'Success... ' . mysqli_get_host_info($link) . '\n';
mysqli_close($link);
?>

The above examples will output: 

Success... MariaDB host info: localhost via TCP/IP

Notes

Note

MySQLnd always assumes the server default charset. This charset is sent during connection hand-shake/authentication, which mysqlnd will use.

Libmysql uses the default charset set in the my.cnf or by an explicit call to mysqli_options prior to calling mysqli_real_connect, but after mysqli_init.

See Also

mysqli_connect
mysqli_init
mysqli_options
mysqli_ssl_set
mysqli_close
mysqli::real_escape_string, mysqli_real_escape_string

Description

Object oriented stylestring mysqli::escape_string(string escapestr);
string mysqli::real_escape_string(string escapestr);

Procedural stylestring mysqli_real_escape_string(mysqli link,
string escapestr);

This function is used to create a legal SQL string that you can use in an SQL statement. The given string is encoded to an escaped SQL string, taking into account the current character set of the connection.

Parameters

link

Procedural style only: A link identifier returned by mysqli_connect or mysqli_init

escapestr

The string to be escaped.

Characters encoded are NUL (ASCII 0), \n, \r, \, ', ', and Control-Z.

Return Values

Returns an escaped string.

Examples

Example 20.132. mysqli::real_escape_string example

Object oriented style 

<?php
$mysqli = new mysqli('localhost', 'my_user', 'my_password', 'world');
/* check connection */
if (mysqli_connect_errno()) {
 printf('Connect failed: %s\n', mysqli_connect_error());
 exit();
}
$mysqli->query('CREATE TEMPORARY TABLE myCity LIKE City');
$city = ''s Hertogenbosch';
/* this query will fail, cause we didn't escape $city */
if (!$mysqli->query('INSERT into myCity (Name) VALUES ('$city')')) {
 printf('Error: %s\n', $mysqli->sqlstate);
}
$city = $mysqli->real_escape_string($city);
/* this query with escaped $city will work */
if ($mysqli->query('INSERT into myCity (Name) VALUES ('$city')')) {
 printf('%d Row inserted.\n', $mysqli->affected_rows);
}
$mysqli->close();
?>

Procedural style 

<?php
$link = mysqli_connect('localhost', 'my_user', 'my_password', 'world');
/* check connection */
if (mysqli_connect_errno()) {
 printf('Connect failed: %s\n', mysqli_connect_error());
 exit();
}
mysqli_query($link, 'CREATE TEMPORARY TABLE myCity LIKE City');
$city = ''s Hertogenbosch';
/* this query will fail, cause we didn't escape $city */
if (!mysqli_query($link, 'INSERT into myCity (Name) VALUES ('$city')')) {
 printf('Error: %s\n', mysqli_sqlstate($link));
}
$city = mysqli_real_escape_string($link, $city);
/* this query with escaped $city will work */
if (mysqli_query($link, 'INSERT into myCity (Name) VALUES ('$city')')) {
 printf('%d Row inserted.\n', mysqli_affected_rows($link));
}
mysqli_close($link);
?>

The above examples will output: 

Error: 42000
1 Row inserted.

Notes

Note

For those accustomed to using mysql_real_escape_string, note that the arguments of mysqli_real_escape_string differ from what mysql_real_escape_string expects. The link identifier comes first in mysqli_real_escape_string, whereas the string to be escaped comes first in mysql_real_escape_string.

See Also

mysqli_character_set_name
mysqli::real_query, mysqli_real_query

Description

Object oriented stylebool mysqli::real_query(string query);

Procedural stylebool mysqli_real_query(mysqli link,
string query);

Executes a single query against the database whose result can then be retrieved or stored using the mysqli_store_result or mysqli_use_result functions.

In order to determine if a given query should return a result set or not, see mysqli_field_count.

Parameters

link

Procedural style only: A link identifier returned by mysqli_connect or mysqli_init

query

The query, as a string.

Data inside the query should be properly escaped.

Return Values

Returns TRUE on success or FALSE on failure.

See Also

mysqli_query
mysqli_store_result
mysqli_use_result
mysqli::reap_async_query, mysqli_reap_async_query

Description

Object oriented stylepublic mysqli_result mysqli::reap_async_query();

Procedural stylemysqli_result mysqli_reap_async_query(mysql link); Warning

This function is currently not documented; only its argument list is available.

Get result from async query. Available only with mysqlnd.

Parameters

link

Procedural style only: A link identifier returned by mysqli_connect or mysqli_init

Return Values

Returns mysqli_result in success, FALSE otherwise.

See Also

mysqli_poll
mysqli::refresh, mysqli_refresh

Description

Object oriented stylepublic bool mysqli::refresh(int options);

Procedural styleint mysqli_refresh(resource link,
int options);

Flushes tables or caches, or resets the replication server information.

Parameters

link

Procedural style only: A link identifier returned by mysqli_connect or mysqli_init

options

The options to refresh, using the MYSQLI_REFRESH_* constants as documented within the MySQLi constants documentation.

See also the official MySQL Refresh documentation.

Return Values

TRUE if the refresh was a success, otherwise FALSE

See Also

mysqli_poll
mysqli::rollback, mysqli_rollback

Description

Object oriented stylebool mysqli::rollback();

Procedural stylebool mysqli_rollback(mysqli link);

Rollbacks the current transaction for the database.

Parameters

link

Procedural style only: A link identifier returned by mysqli_connect or mysqli_init

Return Values

Returns TRUE on success or FALSE on failure.

Examples

Example 20.133. mysqli::rollback example

Object oriented style 

<?php
$mysqli = new mysqli('localhost', 'my_user', 'my_password', 'world');
/* check connection */
if (mysqli_connect_errno()) {
 printf('Connect failed: %s\n', mysqli_connect_error());
 exit();
}
/* disable autocommit */
$mysqli->autocommit(FALSE);
$mysqli->query('CREATE TABLE myCity LIKE City');
$mysqli->query('ALTER TABLE myCity Type=InnoDB');
$mysqli->query('INSERT INTO myCity SELECT * FROM City LIMIT 50');
/* commit insert */
$mysqli->commit();
/* delete all rows */
$mysqli->query('DELETE FROM myCity');
if ($result = $mysqli->query('SELECT COUNT(*) FROM myCity')) {
 $row = $result->fetch_row();
 printf('%d rows in table myCity.\n', $row[0]);
 /* Free result */
 $result->close();
}
/* Rollback */
$mysqli->rollback();
if ($result = $mysqli->query('SELECT COUNT(*) FROM myCity')) {
 $row = $result->fetch_row();
 printf('%d rows in table myCity (after rollback).\n', $row[0]);
 /* Free result */
 $result->close();
}
/* Drop table myCity */
$mysqli->query('DROP TABLE myCity');
$mysqli->close();
?>

Procedural style 

<?php
$link = mysqli_connect('localhost', 'my_user', 'my_password', 'world');
/* check connection */
if (mysqli_connect_errno()) {
 printf('Connect failed: %s\n', mysqli_connect_error());
 exit();
}
/* disable autocommit */
mysqli_autocommit($link, FALSE);
mysqli_query($link, 'CREATE TABLE myCity LIKE City');
mysqli_query($link, 'ALTER TABLE myCity Type=InnoDB');
mysqli_query($link, 'INSERT INTO myCity SELECT * FROM City LIMIT 50');
/* commit insert */
mysqli_commit($link);
/* delete all rows */
mysqli_query($link, 'DELETE FROM myCity');
if ($result = mysqli_query($link, 'SELECT COUNT(*) FROM myCity')) {
 $row = mysqli_fetch_row($result);
 printf('%d rows in table myCity.\n', $row[0]);
 /* Free result */
 mysqli_free_result($result);
}
/* Rollback */
mysqli_rollback($link);
if ($result = mysqli_query($link, 'SELECT COUNT(*) FROM myCity')) {
 $row = mysqli_fetch_row($result);
 printf('%d rows in table myCity (after rollback).\n', $row[0]);
 /* Free result */
 mysqli_free_result($result);
}
/* Drop table myCity */
mysqli_query($link, 'DROP TABLE myCity');
mysqli_close($link);
?>

The above examples will output: 

0 rows in table myCity.
50 rows in table myCity (after rollback).

See Also

mysqli_commit
mysqli_autocommit
mysqli::rpl_query_type, mysqli_rpl_query_type

Description

Object oriented styleint mysqli::rpl_query_type(string query);

Procedural styleint mysqli_rpl_query_type(mysqli link,
string query);

Returns MYSQLI_RPL_MASTER , MYSQLI_RPL_SLAVE or MYSQLI_RPL_ADMIN depending on a query type. INSERT, UPDATE and similar are master queries, SELECT is slave, and FLUSH, REPAIR and similar are admin.Warning

This function is currently not documented; only its argument list is available.Warning

This function has been DEPRECATED and REMOVED as of PHP 5.3.0.

mysqli::select_db, mysqli_select_db

Description

Object oriented stylebool mysqli::select_db(string dbname);

Procedural stylebool mysqli_select_db(mysqli link,
string dbname);

Selects the default database to be used when performing queries against the database connection.Note

This function should only be used to change the default database for the connection. You can select the default database with 4th parameter in mysqli_connect.

Parameters

link

Procedural style only: A link identifier returned by mysqli_connect or mysqli_init

dbname

The database name.

Return Values

Returns TRUE on success or FALSE on failure.

Examples

Example 20.134. mysqli::select_db example

Object oriented style 

<?php
$mysqli = new mysqli('localhost', 'my_user', 'my_password', 'test');
/* check connection */
if (mysqli_connect_errno()) {
 printf('Connect failed: %s\n', mysqli_connect_error());
 exit();
}
/* return name of current default database */
if ($result = $mysqli->query('SELECT DATABASE()')) {
 $row = $result->fetch_row();
 printf('Default database is %s.\n', $row[0]);
 $result->close();
}
/* change db to world db */
$mysqli->select_db('world');
/* return name of current default database */
if ($result = $mysqli->query('SELECT DATABASE()')) {
 $row = $result->fetch_row();
 printf('Default database is %s.\n', $row[0]);
 $result->close();
}
$mysqli->close();
?>

Procedural style 

<?php
$link = mysqli_connect('localhost', 'my_user', 'my_password', 'test');
/* check connection */
if (mysqli_connect_errno()) {
 printf('Connect failed: %s\n', mysqli_connect_error());
 exit();
}
/* return name of current default database */
if ($result = mysqli_query($link, 'SELECT DATABASE()')) {
 $row = mysqli_fetch_row($result);
 printf('Default database is %s.\n', $row[0]);
 mysqli_free_result($result);
}
/* change db to world db */
mysqli_select_db($link, 'world');
/* return name of current default database */
if ($result = mysqli_query($link, 'SELECT DATABASE()')) {
 $row = mysqli_fetch_row($result);
 printf('Default database is %s.\n', $row[0]);
 mysqli_free_result($result);
}
mysqli_close($link);
?>

The above examples will output: 

Default database is test.
Default database is world.

See Also

mysqli_connect
mysqli_real_connect
mysqli::send_query, mysqli_send_query

Description

Object oriented stylebool mysqli::send_query(string query);

Procedural stylebool mysqli_send_query(mysqli link,
string query); Warning

This function is currently not documented; only its argument list is available.Warning

This function has been DEPRECATED and REMOVED as of PHP 5.3.0.

mysqli::set_charset, mysqli_set_charset

Description

Object oriented stylebool mysqli::set_charset(string charset);

Procedural stylebool mysqli_set_charset(mysqli link,
string charset);

Sets the default character set to be used when sending data from and to the database server.

Parameters

link

Procedural style only: A link identifier returned by mysqli_connect or mysqli_init

charset

The charset to be set as default.

Return Values

Returns TRUE on success or FALSE on failure.

Notes

Note

To use this function on a Windows platform you need MariaDB client library version 4.1.11 or above (for MariaDB 5.0 you need 5.0.6 or above).Note

This is the preferred way to change the charset. Using mysqli::query to execute SET NAMES .. is not recommended.

Examples

Example 20.135. mysqli::set_charset example

Object oriented style 

<?php
$mysqli = new mysqli('localhost', 'my_user', 'my_password', 'test');
/* check connection */
if (mysqli_connect_errno()) {
 printf('Connect failed: %s\n', mysqli_connect_error());
 exit();
}
/* change character set to utf8 */
if (!$mysqli->set_charset('utf8')) {
 printf('Error loading character set utf8: %s\n', $mysqli->error);
} else {
 printf('Current character set: %s\n', $mysqli->character_set_name());
}
$mysqli->close();
?>

Procedural style 

<?php
$link = mysqli_connect('localhost', 'my_user', 'my_password', 'test');
/* check connection */
if (mysqli_connect_errno()) {
 printf('Connect failed: %s\n', mysqli_connect_error());
 exit();
}
/* change character set to utf8 */
if (!mysqli_set_charset($link, 'utf8')) {
 printf('Error loading character set utf8: %s\n', mysqli_error($link));
} else {
 printf('Current character set: %s\n', mysqli_character_set_name($link));
}
mysqli_close($link);
?>

The above examples will output: 

Current character set: utf8

See Also

mysqli_character_set_name
mysqli_real_escape_string
List of character sets that MariaDB supports
mysqli::set_local_infile_default, mysqli_set_local_infile_default

Description

void mysqli_set_local_infile_default(mysqli link);

Deactivates a LOAD DATA INFILE LOCAL handler previously set with mysqli_set_local_infile_handler.

Parameters

link

Procedural style only: A link identifier returned by mysqli_connect or mysqli_init

Return Values

No value is returned.

Examples

See mysqli_set_local_infile_handler examples

See Also

mysqli_set_local_infile_handler
mysqli::set_local_infile_handler, mysqli_set_local_infile_handler

Description

Object oriented stylebool mysqli::set_local_infile_handler(mysqli link,
callable read_func);

Procedural stylebool mysqli_set_local_infile_handler(mysqli link,
callable read_func);

Set callback function for LOAD DATA LOCAL INFILE command

The callbacks task is to read input from the file specified in the LOAD DATA LOCAL INFILE and to reformat it into the format understood by LOAD DATA INFILE.

The returned data needs to match the format specified in the LOAD DATA

Parameters

link

Procedural style only: A link identifier returned by mysqli_connect or mysqli_init

read_func

A callback function or object method taking the following parameters:

stream

A PHP stream associated with the SQL commands INFILE

&buffer

A string buffer to store the rewritten input into

buflen

The maximum number of characters to be stored in the buffer

&errormsg

If an error occurs you can store an error message in here

The callback function should return the number of characters stored in the buffer or a negative value if an error occurred.

Return Values

Returns TRUE on success or FALSE on failure.

Examples

Example 20.136. mysqli::set_local_infile_handler example

Object oriented style 

<?php
 $db = mysqli_init();
 $db->real_connect('localhost','root','','test');
 function callme($stream, &$buffer, $buflen, &$errmsg)
 {
 $buffer = fgets($stream);
 echo $buffer;
 // convert to upper case and replace ',' delimiter with [TAB]
 $buffer = strtoupper(str_replace(',', '\t', $buffer));
 return strlen($buffer);
 }
 echo 'Input:\n';
 $db->set_local_infile_handler('callme');
 $db->query('LOAD DATA LOCAL INFILE 'input.txt' INTO TABLE t1');
 $db->set_local_infile_default();
 $res = $db->query('SELECT * FROM t1');
 echo '\nResult:\n';
 while ($row = $res->fetch_assoc()) {
 echo join(',', $row).'\n';
 }
?>

Procedural style 

<?php
 $db = mysqli_init();
 mysqli_real_connect($db, 'localhost','root','','test');
 function callme($stream, &$buffer, $buflen, &$errmsg)
 {
 $buffer = fgets($stream);
 echo $buffer;
 // convert to upper case and replace ',' delimiter with [TAB]
 $buffer = strtoupper(str_replace(',', '\t', $buffer));
 return strlen($buffer);
 }
 echo 'Input:\n';
 mysqli_set_local_infile_handler($db, 'callme');
 mysqli_query($db, 'LOAD DATA LOCAL INFILE 'input.txt' INTO TABLE t1');
 mysqli_set_local_infile_default($db);
 $res = mysqli_query($db, 'SELECT * FROM t1');
 echo '\nResult:\n';
 while ($row = mysqli_fetch_assoc($res)) {
 echo join(',', $row).'\n';
 }
?>

The above examples will output: 

Input:
23,foo
42,bar Output:
23,FOO
42,BAR

See Also

mysqli_set_local_infile_default
mysqli::$sqlstate, mysqli_sqlstate

Description

Object oriented stylestring mysqli->sqlstate ;

Procedural stylestring mysqli_sqlstate(mysqli link);

Returns a string containing the SQLSTATE error code for the last error. The error code consists of five characters. '00000' means no error. The values are specified by ANSI SQL and ODBC. For a list of possible values, see http://dev.mysql.com/doc/mysql/en/error-handling.html.Note

Note that not all MariaDB errors are yet mapped to SQLSTATE's. The value HY000 (general error) is used for unmapped errors.

Parameters

link

Procedural style only: A link identifier returned by mysqli_connect or mysqli_init

Return Values

Returns a string containing the SQLSTATE error code for the last error. The error code consists of five characters. '00000' means no error.

Examples

Example 20.137. $mysqli->sqlstate example

Object oriented style 

<?php
$mysqli = new mysqli('localhost', 'my_user', 'my_password', 'world');
/* check connection */
if (mysqli_connect_errno()) {
 printf('Connect failed: %s\n', mysqli_connect_error());
 exit();
}
/* Table City already exists, so we should get an error */
if (!$mysqli->query('CREATE TABLE City (ID INT, Name VARCHAR(30))')) {
 printf('Error - SQLSTATE %s.\n', $mysqli->sqlstate);
}
$mysqli->close();
?>

Procedural style 

<?php
$link = mysqli_connect('localhost', 'my_user', 'my_password', 'world');
/* check connection */
if (mysqli_connect_errno()) {
 printf('Connect failed: %s\n', mysqli_connect_error());
 exit();
}
/* Table City already exists, so we should get an error */
if (!mysqli_query($link, 'CREATE TABLE City (ID INT, Name VARCHAR(30))')) {
 printf('Error - SQLSTATE %s.\n', mysqli_sqlstate($link));
}
mysqli_close($link);
?>

The above examples will output: 

Error - SQLSTATE 42S01.

See Also

mysqli_errno
mysqli_error
mysqli::ssl_set, mysqli_ssl_set

Description

Object oriented stylebool mysqli::ssl_set(string key,
string cert,
string ca,
string capath,
string cipher);

Procedural stylebool mysqli_ssl_set(mysqli link,
string key,
string cert,
string ca,
string capath,
string cipher);

Used for establishing secure connections using SSL. It must be called before mysqli_real_connect. This function does nothing unless OpenSSL support is enabled.

Note that MariaDB Native Driver does not support SSL before PHP 5.3.3, so calling this function when using MariaDB Native Driver will result in an error. MariaDB Native Driver is enabled by default on Microsoft Windows from PHP version 5.3 onwards.

Parameters

link

Procedural style only: A link identifier returned by mysqli_connect or mysqli_init

key

The path name to the key file.

cert

The path name to the certificate file.

ca

The path name to the certificate authority file.

capath

The pathname to a directory that contains trusted SSL CA certificates in PEM format.

cipher

A list of allowable ciphers to use for SSL encryption.

Any unused SSL parameters may be given as NULL

Return Values

This function always returns TRUE value. If SSL setup is incorrect mysqli_real_connect will return an error when you attempt to connect.

See Also

mysqli_options
mysqli_real_connect
mysqli::stat, mysqli_stat

Description

Object oriented stylestring mysqli::stat();

Procedural stylestring mysqli_stat(mysqli link);

mysqli_stat returns a string containing information similar to that provided by the 'mysqladmin status' command. This includes uptime in seconds and the number of running threads, questions, reloads, and open tables.

Parameters

link

Procedural style only: A link identifier returned by mysqli_connect or mysqli_init

Return Values

A string describing the server status. FALSE if an error occurred.

Examples

Example 20.138. mysqli::stat example

Object oriented style 

<?php
$mysqli = new mysqli('localhost', 'my_user', 'my_password', 'world');
/* check connection */
if (mysqli_connect_errno()) {
 printf('Connect failed: %s\n', mysqli_connect_error());
 exit();
}
printf ('System status: %s\n', $mysqli->stat());
$mysqli->close();
?>

Procedural style 

<?php
$link = mysqli_connect('localhost', 'my_user', 'my_password', 'world');
/* check connection */
if (mysqli_connect_errno()) {
 printf('Connect failed: %s\n', mysqli_connect_error());
 exit();
}
printf('System status: %s\n', mysqli_stat($link));
mysqli_close($link);
?>

The above examples will output: 

System status: Uptime: 272 Threads: 1 Questions: 5340 Slow queries: 0
Opens: 13 Flush tables: 1 Open tables: 0 Queries per second avg: 19.632
Memory in use: 8496K Max memory used: 8560K

See Also

mysqli_get_server_info
mysqli::stmt_init, mysqli_stmt_init

Description

Object oriented stylemysqli_stmt mysqli::stmt_init();

Procedural stylemysqli_stmt mysqli_stmt_init(mysqli link);

Allocates and initializes a statement object suitable for mysqli_stmt_prepare.Note

Any subsequent calls to any mysqli_stmt function will fail until mysqli_stmt_prepare was called.

Parameters

link

Procedural style only: A link identifier returned by mysqli_connect or mysqli_init

Return Values

Returns an object.

See Also

mysqli_stmt_prepare
mysqli::store_result, mysqli_store_result

Description

Object oriented stylemysqli_result mysqli::store_result();

Procedural stylemysqli_result mysqli_store_result(mysqli link);

Transfers the result set from the last query on the database connection represented by the link parameter to be used with the mysqli_data_seek function.

Parameters

link

Procedural style only: A link identifier returned by mysqli_connect or mysqli_init

Return Values

Returns a buffered result object or FALSE if an error occurred.Note

mysqli_store_result returns FALSE in case the query didn't return a result set (if the query was, for example an INSERT statement). This function also returns FALSE if the reading of the result set failed. You can check if you have got an error by checking if mysqli_error doesn't return an empty string, if mysqli_errno returns a non zero value, or if mysqli_field_count returns a non zero value. Also possible reason for this function returning FALSE after successful call to mysqli_query can be too large result set (memory for it cannot be allocated). If mysqli_field_count returns a non-zero value, the statement should have produced a non-empty result set.

Notes

Note

Although it is always good practice to free the memory used by the result of a query using the mysqli_free_result function, when transferring large result sets using the mysqli_store_result this becomes particularly important.

Examples

See mysqli_multi_query.

See Also

mysqli_real_query
mysqli_use_result
mysqli::$thread_id, mysqli_thread_id

Description

Object oriented styleint mysqli->thread_id ;

Procedural styleint mysqli_thread_id(mysqli link);

The mysqli_thread_id function returns the thread ID for the current connection which can then be killed using the mysqli_kill function. If the connection is lost and you reconnect with mysqli_ping, the thread ID will be other. Therefore you should get the thread ID only when you need it.Note

The thread ID is assigned on a connection-by-connection basis. Hence, if the connection is broken and then re-established a new thread ID will be assigned.

To kill a running query you can use the SQL command KILL QUERY processid.

Parameters

link

Procedural style only: A link identifier returned by mysqli_connect or mysqli_init

Return Values

Returns the Thread ID for the current connection.

Examples

Example 20.139. $mysqli->thread_id example

Object oriented style 

<?php
$mysqli = new mysqli('localhost', 'my_user', 'my_password', 'world');
/* check connection */
if (mysqli_connect_errno()) {
 printf('Connect failed: %s\n', mysqli_connect_error());
 exit();
}
/* determine our thread id */
$thread_id = $mysqli->thread_id;
/* Kill connection */
$mysqli->kill($thread_id);
/* This should produce an error */
if (!$mysqli->query('CREATE TABLE myCity LIKE City')) {
 printf('Error: %s\n', $mysqli->error);
 exit;
}
/* close connection */
$mysqli->close();
?>

Procedural style 

<?php
$link = mysqli_connect('localhost', 'my_user', 'my_password', 'world');
/* check connection */
if (mysqli_connect_errno()) {
 printf('Connect failed: %s\n', mysqli_connect_error());
 exit();
}
/* determine our thread id */
$thread_id = mysqli_thread_id($link);
/* Kill connection */
mysqli_kill($link, $thread_id);
/* This should produce an error */
if (!mysqli_query($link, 'CREATE TABLE myCity LIKE City')) {
 printf('Error: %s\n', mysqli_error($link));
 exit;
}
/* close connection */
mysqli_close($link);
?>

The above examples will output: 

Error: MariaDB server has gone away

See Also

mysqli_kill
mysqli::thread_safe, mysqli_thread_safe

Description

Procedural stylebool mysqli_thread_safe();

Tells whether the client library is compiled as thread-safe.

Return Values

TRUE if the client library is thread-safe, otherwise FALSE .

mysqli::use_result, mysqli_use_result

Description

Object oriented stylemysqli_result mysqli::use_result();

Procedural stylemysqli_result mysqli_use_result(mysqli link);

Used to initiate the retrieval of a result set from the last query executed using the mysqli_real_query function on the database connection.

Either this or the mysqli_store_result function must be called before the results of a query can be retrieved, and one or the other must be called to prevent the next query on that database connection from failing.Note

The mysqli_use_result function does not transfer the entire result set from the database and hence cannot be used functions such as mysqli_data_seek to move to a particular row within the set. To use this functionality, the result set must be stored using mysqli_store_result. One should not use mysqli_use_result if a lot of processing on the client side is performed, since this will tie up the server and prevent other threads from updating any tables from which the data is being fetched.

Return Values

Returns an unbuffered result object or FALSE if an error occurred.

Examples

Example 20.140. mysqli::use_result example

Object oriented style 

<?php
$mysqli = new mysqli('localhost', 'my_user', 'my_password', 'world');
/* check connection */
if (mysqli_connect_errno()) {
 printf('Connect failed: %s\n', mysqli_connect_error());
 exit();
}
$query = 'SELECT CURRENT_USER();';
$query .= 'SELECT Name FROM City ORDER BY ID LIMIT 20, 5';
/* execute multi query */
if ($mysqli->multi_query($query)) {
 do {
 /* store first result set */
 if ($result = $mysqli->use_result()) {
 while ($row = $result->fetch_row()) {
 printf('%s\n', $row[0]);
 }
 $result->close();
 }
 /* print divider */
 if ($mysqli->more_results()) {
 printf('-----------------\n');
 }
 } while ($mysqli->next_result());
}
/* close connection */
$mysqli->close();
?>

Procedural style 

<?php
$link = mysqli_connect('localhost', 'my_user', 'my_password', 'world');
/* check connection */
if (mysqli_connect_errno()) {
 printf('Connect failed: %s\n', mysqli_connect_error());
 exit();
}
$query = 'SELECT CURRENT_USER();';
$query .= 'SELECT Name FROM City ORDER BY ID LIMIT 20, 5';
/* execute multi query */
if (mysqli_multi_query($link, $query)) {
 do {
 /* store first result set */
 if ($result = mysqli_use_result($link)) {
 while ($row = mysqli_fetch_row($result)) {
 printf('%s\n', $row[0]);
 }
 mysqli_free_result($result);
 }
 /* print divider */
 if (mysqli_more_results($link)) {
 printf('-----------------\n');
 }
 } while (mysqli_next_result($link));
}
/* close connection */
mysqli_close($link);
?>

The above examples will output: 

my_user@localhost
-----------------
Amersfoort Maastricht Dordrecht Leiden Haarlemmermeer

See Also

mysqli_real_query
mysqli_store_result
mysqli::$warning_count, mysqli_warning_count

Description

Object oriented styleint mysqli->warning_count ;

Procedural styleint mysqli_warning_count(mysqli link);

Returns the number of warnings from the last query in the connection.Note

For retrieving warning messages you can use the SQL command SHOW WARNINGS [limit row_count].

Parameters

link

Procedural style only: A link identifier returned by mysqli_connect or mysqli_init

Return Values

Number of warnings or zero if there are no warnings.

Examples

Example 20.141. $mysqli->warning_count example

Object oriented style 

<?php
$mysqli = new mysqli('localhost', 'my_user', 'my_password', 'world');
/* check connection */
if (mysqli_connect_errno()) {
 printf('Connect failed: %s\n', mysqli_connect_error());
 exit();
}
$mysqli->query('CREATE TABLE myCity LIKE City');
/* a remarkable city in Wales */
$query = 'INSERT INTO myCity (CountryCode, Name) VALUES('GBR',
 'Llanfairpwllgwyngyllgogerychwyrndrobwllllantysiliogogogoch')';
$mysqli->query($query);
if ($mysqli->warning_count) {
 if ($result = $mysqli->query('SHOW WARNINGS')) {
 $row = $result->fetch_row();
 printf('%s (%d): %s\n', $row[0], $row[1], $row[2]);
 $result->close();
 }
}
/* close connection */
$mysqli->close();
?>

Procedural style 

<?php
$link = mysqli_connect('localhost', 'my_user', 'my_password', 'world');
/* check connection */
if (mysqli_connect_errno()) {
 printf('Connect failed: %s\n', mysqli_connect_error());
 exit();
}
mysqli_query($link, 'CREATE TABLE myCity LIKE City');
/* a remarkable long city name in Wales */
$query = 'INSERT INTO myCity (CountryCode, Name) VALUES('GBR',
 'Llanfairpwllgwyngyllgogerychwyrndrobwllllantysiliogogogoch')';
mysqli_query($link, $query);
if (mysqli_warning_count($link)) {
 if ($result = mysqli_query($link, 'SHOW WARNINGS')) {
 $row = mysqli_fetch_row($result);
 printf('%s (%d): %s\n', $row[0], $row[1], $row[2]);
 mysqli_free_result($result);
 }
}
/* close connection */
mysqli_close($link);
?>

The above examples will output: 

Warning (1264): Data truncated for column 'Name' at row 1

See Also

mysqli_errno
mysqli_error
mysqli_sqlstate

The mysqli_stmt class (mysqli_stmt)

mysqli_stmt::$affected_rows, mysqli_stmt_affected_rows
mysqli_stmt::attr_get, mysqli_stmt_attr_get
mysqli_stmt::attr_set, mysqli_stmt_attr_set
mysqli_stmt::bind_param, mysqli_stmt_bind_param
mysqli_stmt::bind_result, mysqli_stmt_bind_result
mysqli_stmt::close, mysqli_stmt_close
mysqli_stmt::data_seek, mysqli_stmt_data_seek
mysqli_stmt::$errno, mysqli_stmt_errno
mysqli_stmt::$error_list, mysqli_stmt_error_list
mysqli_stmt::$error, mysqli_stmt_error
mysqli_stmt::execute, mysqli_stmt_execute
mysqli_stmt::fetch, mysqli_stmt_fetch
mysqli_stmt::$field_count, mysqli_stmt_field_count
mysqli_stmt::free_result, mysqli_stmt_free_result
mysqli_stmt::get_result, mysqli_stmt_get_result
mysqli_stmt::get_warnings, mysqli_stmt_get_warnings
mysqli_stmt::$insert_id, mysqli_stmt_insert_id
mysqli_stmt::more_results, mysqli_stmt_more_results
mysqli_stmt::next_result, mysqli_stmt_next_result
mysqli_stmt::$num_rows, mysqli_stmt_num_rows
mysqli_stmt::$param_count, mysqli_stmt_param_count
mysqli_stmt::prepare, mysqli_stmt_prepare
mysqli_stmt::reset, mysqli_stmt_reset
mysqli_stmt::result_metadata, mysqli_stmt_result_metadata
mysqli_stmt::send_long_data, mysqli_stmt_send_long_data
mysqli_stmt::$sqlstate, mysqli_stmt_sqlstate
mysqli_stmt::store_result, mysqli_stmt_store_result

Represents a prepared statement. 

 mysqli_stmt {

 mysqli_stmt
 Properties int mysqli_stmt->affected_rows ;

 int mysqli_stmt->errno ;

 string mysqli_stmt->error_list ;

 string mysqli_stmt->error ;

 int mysqli_stmt->field_count ;

 int mysqli_stmt->insert_id ;

 int mysqli_stmt->num_rows ;

 int mysqli_stmt->param_count ;

 string mysqli_stmt->sqlstate ;

Methods int mysqli_stmt::attr_get(int attr);

 bool mysqli_stmt::attr_set(int attr,

 int mode);

 bool mysqli_stmt::bind_param(string types,

 mixed var1,

 mixed ...);

 bool mysqli_stmt::bind_result(mixed var1,

 mixed ...);

 bool mysqli_stmt::close();

 void mysqli_stmt::data_seek(int offset);

 bool mysqli_stmt::execute();

 bool mysqli_stmt::fetch();

 void mysqli_stmt::free_result();

 mysqli_result mysqli_stmt::get_result();

 object mysqli_stmt::get_warnings(mysqli_stmt stmt);

 mixed mysqli_stmt::prepare(string query);

 bool mysqli_stmt::reset();

 mysqli_result mysqli_stmt::result_metadata();

 bool mysqli_stmt::send_long_data(int param_nr,

 string data);

 bool mysqli_stmt::store_result();

}
mysqli_stmt::$affected_rows, mysqli_stmt_affected_rows

Description

Object oriented styleint mysqli_stmt->affected_rows ;

Procedural styleint mysqli_stmt_affected_rows(mysqli_stmt stmt);

Returns the number of rows affected by INSERT, UPDATE, or DELETE query.

This function only works with queries which update a table. In order to get the number of rows from a SELECT query, use mysqli_stmt_num_rows instead.

Parameters

stmt

Procedural style only: A statement identifier returned by mysqli_stmt_init.

Return Values

An integer greater than zero indicates the number of rows affected or retrieved. Zero indicates that no records where updated for an UPDATE/DELETE statement, no rows matched the WHERE clause in the query or that no query has yet been executed. -1 indicates that the query has returned an error. NULL indicates an invalid argument was supplied to the function.Note

If the number of affected rows is greater than maximal PHP int value, the number of affected rows will be returned as a string value.

Examples

Example 20.142. Object oriented style

<?php
$mysqli = new mysqli('localhost', 'my_user', 'my_password', 'world');
/* check connection */
if (mysqli_connect_errno()) {
 printf('Connect failed: %s\n', mysqli_connect_error());
 exit();
}
/* create temp table */
$mysqli->query('CREATE TEMPORARY TABLE myCountry LIKE Country');
$query = 'INSERT INTO myCountry SELECT * FROM Country WHERE Code LIKE ?';
/* prepare statement */
if ($stmt = $mysqli->prepare($query)) {
 /* Bind variable for placeholder */
 $code = 'A%';
 $stmt->bind_param('s', $code);
 /* execute statement */
 $stmt->execute();
 printf('rows inserted: %d\n', $stmt->affected_rows);
 /* close statement */
 $stmt->close();
}
/* close connection */
$mysqli->close();
?>

Example 20.143. Procedural style

<?php
$link = mysqli_connect('localhost', 'my_user', 'my_password', 'world');
/* check connection */
if (mysqli_connect_errno()) {
 printf('Connect failed: %s\n', mysqli_connect_error());
 exit();
}
/* create temp table */
mysqli_query($link, 'CREATE TEMPORARY TABLE myCountry LIKE Country');
$query = 'INSERT INTO myCountry SELECT * FROM Country WHERE Code LIKE ?';
/* prepare statement */
if ($stmt = mysqli_prepare($link, $query)) {
 /* Bind variable for placeholder */
 $code = 'A%';
 mysqli_stmt_bind_param($stmt, 's', $code);
 /* execute statement */
 mysqli_stmt_execute($stmt);
 printf('rows inserted: %d\n', mysqli_stmt_affected_rows($stmt));
 /* close statement */
 mysqli_stmt_close($stmt);
}
/* close connection */
mysqli_close($link);
?>

The above examples will output: 

rows inserted: 17

See Also

mysqli_stmt_num_rows
mysqli_prepare
mysqli_stmt::attr_get, mysqli_stmt_attr_get

Description

Object oriented styleint mysqli_stmt::attr_get(int attr);

Procedural styleint mysqli_stmt_attr_get(mysqli_stmt stmt,
int attr);

Gets the current value of a statement attribute.

Parameters

stmt

Procedural style only: A statement identifier returned by mysqli_stmt_init.

attr

The attribute that you want to get.

Return Values

Returns FALSE if the attribute is not found, otherwise returns the value of the attribute.

mysqli_stmt::attr_set, mysqli_stmt_attr_set

Description

Object oriented stylebool mysqli_stmt::attr_set(int attr,
int mode);

Procedural stylebool mysqli_stmt_attr_set(mysqli_stmt stmt,
int attr,
int mode);

Used to modify the behavior of a prepared statement. This function may be called multiple times to set several attributes.

Parameters

stmt

Procedural style only: A statement identifier returned by mysqli_stmt_init.

attr

The attribute that you want to set. It can have one of the following values:

Table 20.17. Attribute values

Character Description
MYSQLI_STMT_ATTR_UPDATE_MAX_LENGTH If set to 1, causes mysqli_stmt_store_result to update the metadata MYSQL_FIELD->max_length value.
MYSQLI_STMT_ATTR_CURSOR_TYPE Type of cursor to open for statement when mysqli_stmt_execute is invoked. mode can be MYSQLI_CURSOR_TYPE_NO_CURSOR (the default) or MYSQLI_CURSOR_TYPE_READ_ONLY.
MYSQLI_STMT_ATTR_PREFETCH_ROWS Number of rows to fetch from server at a time when using a cursor. mode can be in the range from 1 to the maximum value of unsigned long. The default is 1.

If you use the MYSQLI_STMT_ATTR_CURSOR_TYPE option with MYSQLI_CURSOR_TYPE_READ_ONLY, a cursor is opened for the statement when you invoke mysqli_stmt_execute. If there is already an open cursor from a previous mysqli_stmt_execute call, it closes the cursor before opening a new one. mysqli_stmt_reset also closes any open cursor before preparing the statement for re-execution. mysqli_stmt_free_result closes any open cursor.

If you open a cursor for a prepared statement, mysqli_stmt_store_result is unnecessary.

mode

The value to assign to the attribute.

mysqli_stmt::bind_param, mysqli_stmt_bind_param

Description

Object oriented stylebool mysqli_stmt::bind_param(string types,
mixed var1,
mixed ...);

Procedural stylebool mysqli_stmt_bind_param(mysqli_stmt stmt,
string types,
mixed var1,
mixed ...);

Bind variables for the parameter markers in the SQL statement that was passed to mysqli_prepare.Note

If data size of a variable exceeds max. allowed packet size (max_allowed_packet), you have to specify b in types and use mysqli_stmt_send_long_data to send the data in packets.Note

Care must be taken when using mysqli_stmt_bind_param in conjunction with call_user_func_array. Note that mysqli_stmt_bind_param requires parameters to be passed by reference, whereas call_user_func_array can accept as a parameter a list of variables that can represent references or values.

Parameters

stmt

Procedural style only: A statement identifier returned by mysqli_stmt_init.

types

A string that contains one or more characters which specify the types for the corresponding bind variables:

Table 20.18. Type specification chars

Character Description
i corresponding variable has type integer
d corresponding variable has type double
s corresponding variable has type string
b corresponding variable is a blob and will be sent in packets
var1

The number of variables and length of string types must match the parameters in the statement.

Return Values

Returns TRUE on success or FALSE on failure.

Examples

Example 20.144. Object oriented style

<?php
$mysqli = new mysqli('localhost', 'my_user', 'my_password', 'world');
/* check connection */
if (mysqli_connect_errno()) {
 printf('Connect failed: %s\n', mysqli_connect_error());
 exit();
}
$stmt = $mysqli->prepare('INSERT INTO CountryLanguage VALUES (?, ?, ?, ?)');
$stmt->bind_param('sssd', $code, $language, $official, $percent);
$code = 'DEU';
$language = 'Bavarian';
$official = 'F';
$percent = 11.2;
/* execute prepared statement */
$stmt->execute();
printf('%d Row inserted.\n', $stmt->affected_rows);
/* close statement and connection */
$stmt->close();
/* Clean up table CountryLanguage */
$mysqli->query('DELETE FROM CountryLanguage WHERE Language="Bavarian"');
printf('%d Row deleted.\n', $mysqli->affected_rows);
/* close connection */
$mysqli->close();
?>

Example 20.145. Procedural style

<?php
$link = mysqli_connect('localhost', 'my_user', 'my_password', 'world');
/* check connection */
if (!$link) {
 printf('Connect failed: %s\n', mysqli_connect_error());
 exit();
}
$stmt = mysqli_prepare($link, 'INSERT INTO CountryLanguage VALUES (?, ?, ?, ?)');
mysqli_stmt_bind_param($stmt, 'sssd', $code, $language, $official, $percent);
$code = 'DEU';
$language = 'Bavarian';
$official = 'F';
$percent = 11.2;
/* execute prepared statement */
mysqli_stmt_execute($stmt);
printf('%d Row inserted.\n', mysqli_stmt_affected_rows($stmt));
/* close statement and connection */
mysqli_stmt_close($stmt);
/* Clean up table CountryLanguage */
mysqli_query($link, 'DELETE FROM CountryLanguage WHERE Language="Bavarian"');
printf('%d Row deleted.\n', mysqli_affected_rows($link));
/* close connection */
mysqli_close($link);
?>

The above examples will output: 

1 Row inserted.
1 Row deleted.

See Also

mysqli_stmt_bind_result
mysqli_stmt_execute
mysqli_stmt_fetch
mysqli_prepare
mysqli_stmt_send_long_data
mysqli_stmt_errno
mysqli_stmt_error
mysqli_stmt::bind_result, mysqli_stmt_bind_result

Description

Object oriented stylebool mysqli_stmt::bind_result(mixed var1,
mixed ...);

Procedural stylebool mysqli_stmt_bind_result(mysqli_stmt stmt,
mixed var1,
mixed ...);

Binds columns in the result set to variables.

When mysqli_stmt_fetch is called to fetch data, the MariaDB client/server protocol places the data for the bound columns into the specified variables var1, ....Note

Note that all columns must be bound after mysqli_stmt_execute and prior to calling mysqli_stmt_fetch. Depending on column types bound variables can silently change to the corresponding PHP type.

A column can be bound or rebound at any time, even after a result set has been partially retrieved. The new binding takes effect the next time mysqli_stmt_fetch is called.

Parameters

stmt

Procedural style only: A statement identifier returned by mysqli_stmt_init.

var1

The variable to be bound.

Return Values

Returns TRUE on success or FALSE on failure.

Examples

Example 20.146. Object oriented style

<?php
$mysqli = new mysqli('localhost', 'my_user', 'my_password', 'world');
if (mysqli_connect_errno()) {
 printf('Connect failed: %s\n', mysqli_connect_error());
 exit();
}
/* prepare statement */
if ($stmt = $mysqli->prepare('SELECT Code, Name FROM Country ORDER BY Name LIMIT 5')) {
 $stmt->execute();
 /* bind variables to prepared statement */
 $stmt->bind_result($col1, $col2);
 /* fetch values */
 while ($stmt->fetch()) {
 printf('%s %s\n', $col1, $col2);
 }
 /* close statement */
 $stmt->close();
}
/* close connection */
$mysqli->close();
?>

Example 20.147. Procedural style

<?php
$link = mysqli_connect('localhost', 'my_user', 'my_password', 'world');
/* check connection */
if (!$link) {
 printf('Connect failed: %s\n', mysqli_connect_error());
 exit();
}
/* prepare statement */
if ($stmt = mysqli_prepare($link, 'SELECT Code, Name FROM Country ORDER BY Name LIMIT 5')) {
 mysqli_stmt_execute($stmt);
 /* bind variables to prepared statement */
 mysqli_stmt_bind_result($stmt, $col1, $col2);
 /* fetch values */
 while (mysqli_stmt_fetch($stmt)) {
 printf('%s %s\n', $col1, $col2);
 }
 /* close statement */
 mysqli_stmt_close($stmt);
}
/* close connection */
mysqli_close($link);
?>

The above examples will output: 

AFG Afghanistan ALB Albania DZA Algeria ASM American Samoa AND Andorra

See Also

mysqli_stmt_bind_param
mysqli_stmt_execute
mysqli_stmt_fetch
mysqli_prepare
mysqli_stmt_prepare
mysqli_stmt_init
mysqli_stmt_errno
mysqli_stmt_error
mysqli_stmt::close, mysqli_stmt_close

Description

Object oriented stylebool mysqli_stmt::close();

Procedural stylebool mysqli_stmt_close(mysqli_stmt stmt);

Closes a prepared statement. mysqli_stmt_close also deallocates the statement handle. If the current statement has pending or unread results, this function cancels them so that the next query can be executed.

Parameters

stmt

Procedural style only: A statement identifier returned by mysqli_stmt_init.

Return Values

Returns TRUE on success or FALSE on failure.

See Also

mysqli_prepare
mysqli_stmt::data_seek, mysqli_stmt_data_seek

Description

Object oriented stylevoid mysqli_stmt::data_seek(int offset);

Procedural stylevoid mysqli_stmt_data_seek(mysqli_stmt stmt,
int offset);

Seeks to an arbitrary result pointer in the statement result set.

mysqli_stmt_store_result must be called prior to mysqli_stmt_data_seek.

Parameters

stmt

Procedural style only: A statement identifier returned by mysqli_stmt_init.

offset

Must be between zero and the total number of rows minus one (0.. mysqli_stmt_num_rows - 1).

Return Values

No value is returned.

Examples

Example 20.148. Object oriented style

<?php
/* Open a connection */
$mysqli = new mysqli('localhost', 'my_user', 'my_password', 'world');
/* check connection */
if (mysqli_connect_errno()) {
 printf('Connect failed: %s\n', mysqli_connect_error());
 exit();
}
$query = 'SELECT Name, CountryCode FROM City ORDER BY Name';
if ($stmt = $mysqli->prepare($query)) {
 /* execute query */
 $stmt->execute();
 /* bind result variables */
 $stmt->bind_result($name, $code);
 /* store result */
 $stmt->store_result();
 /* seek to row no. 400 */
 $stmt->data_seek(399);
 /* fetch values */
 $stmt->fetch();
 printf ('City: %s Countrycode: %s\n', $name, $code);
 /* close statement */
 $stmt->close();
}
/* close connection */
$mysqli->close();
?>

Example 20.149. Procedural style

<?php
/* Open a connection */
$link = mysqli_connect('localhost', 'my_user', 'my_password', 'world');
/* check connection */
if (mysqli_connect_errno()) {
 printf('Connect failed: %s\n', mysqli_connect_error());
 exit();
}
$query = 'SELECT Name, CountryCode FROM City ORDER BY Name';
if ($stmt = mysqli_prepare($link, $query)) {
 /* execute query */
 mysqli_stmt_execute($stmt);
 /* bind result variables */
 mysqli_stmt_bind_result($stmt, $name, $code);
 /* store result */
 mysqli_stmt_store_result($stmt);
 /* seek to row no. 400 */
 mysqli_stmt_data_seek($stmt, 399);
 /* fetch values */
 mysqli_stmt_fetch($stmt);
 printf ('City: %s Countrycode: %s\n', $name, $code);
 /* close statement */
 mysqli_stmt_close($stmt);
}
/* close connection */
mysqli_close($link);
?>

The above examples will output: 

City: Benin City Countrycode: NGA

See Also

mysqli_prepare
mysqli_stmt::$errno, mysqli_stmt_errno

Description

Object oriented styleint mysqli_stmt->errno ;

Procedural styleint mysqli_stmt_errno(mysqli_stmt stmt);

Returns the error code for the most recently invoked statement function that can succeed or fail.

Client error message numbers are listed in the MariaDB errmsg.h header file, server error message numbers are listed in mysqld_error.h. In the MariaDB source distribution you can find a complete list of error messages and error numbers in the file Docs/mysqld_error.txt.

Parameters

stmt

Procedural style only: A statement identifier returned by mysqli_stmt_init.

Return Values

An error code value. Zero means no error occurred.

Examples

Example 20.150. Object oriented style

<?php
/* Open a connection */
$mysqli = new mysqli('localhost', 'my_user', 'my_password', 'world');
/* check connection */
if (mysqli_connect_errno()) {
 printf('Connect failed: %s\n', mysqli_connect_error());
 exit();
}
$mysqli->query('CREATE TABLE myCountry LIKE Country');
$mysqli->query('INSERT INTO myCountry SELECT * FROM Country');
$query = 'SELECT Name, Code FROM myCountry ORDER BY Name';
if ($stmt = $mysqli->prepare($query)) {
 /* drop table */
 $mysqli->query('DROP TABLE myCountry');
 /* execute query */
 $stmt->execute();
 printf('Error: %d.\n', $stmt->errno);
 /* close statement */
 $stmt->close();
}
/* close connection */
$mysqli->close();
?>

Example 20.151. Procedural style

<?php
/* Open a connection */
$link = mysqli_connect('localhost', 'my_user', 'my_password', 'world');
/* check connection */
if (mysqli_connect_errno()) {
 printf('Connect failed: %s\n', mysqli_connect_error());
 exit();
}
mysqli_query($link, 'CREATE TABLE myCountry LIKE Country');
mysqli_query($link, 'INSERT INTO myCountry SELECT * FROM Country');
$query = 'SELECT Name, Code FROM myCountry ORDER BY Name';
if ($stmt = mysqli_prepare($link, $query)) {
 /* drop table */
 mysqli_query($link, 'DROP TABLE myCountry');
 /* execute query */
 mysqli_stmt_execute($stmt);
 printf('Error: %d.\n', mysqli_stmt_errno($stmt));
 /* close statement */
 mysqli_stmt_close($stmt);
}
/* close connection */
mysqli_close($link);
?>

The above examples will output: 

Error: 1146.

See Also

mysqli_stmt_error
mysqli_stmt_sqlstate
mysqli_stmt::$error_list, mysqli_stmt_error_list

Description

Object oriented stylestring mysqli_stmt->error_list ;

Procedural stylestring mysqli_stmt_error_list(mysqli_stmt stmt);

Returns an array of errors for the most recently invoked statement function that can succeed or fail.

Parameters

stmt

Procedural style only: A statement identifier returned by mysqli_stmt_init.

Return Values

A list of errors, each as an associative array containing the errno, error, and sqlstate.

Examples

Example 20.152. Object oriented style

<?php
/* Open a connection */
$mysqli = new mysqli('localhost', 'my_user', 'my_password', 'world');
/* check connection */
if (mysqli_connect_errno()) {
 printf('Connect failed: %s\n', mysqli_connect_error());
 exit();
}
$mysqli->query('CREATE TABLE myCountry LIKE Country');
$mysqli->query('INSERT INTO myCountry SELECT * FROM Country');
$query = 'SELECT Name, Code FROM myCountry ORDER BY Name';
if ($stmt = $mysqli->prepare($query)) {
 /* drop table */
 $mysqli->query('DROP TABLE myCountry');
 /* execute query */
 $stmt->execute();
 echo 'Error:\n';
 print_r($stmt->error_list);
 /* close statement */
 $stmt->close();
}
/* close connection */
$mysqli->close();
?>

Example 20.153. Procedural style

<?php
/* Open a connection */
$link = mysqli_connect('localhost', 'my_user', 'my_password', 'world');
/* check connection */
if (mysqli_connect_errno()) {
 printf('Connect failed: %s\n', mysqli_connect_error());
 exit();
}
mysqli_query($link, 'CREATE TABLE myCountry LIKE Country');
mysqli_query($link, 'INSERT INTO myCountry SELECT * FROM Country');
$query = 'SELECT Name, Code FROM myCountry ORDER BY Name';
if ($stmt = mysqli_prepare($link, $query)) {
 /* drop table */
 mysqli_query($link, 'DROP TABLE myCountry');
 /* execute query */
 mysqli_stmt_execute($stmt);
 echo 'Error:\n';
 print_r(mysql_stmt_error_list($stmt));
 /* close statement */
 mysqli_stmt_close($stmt);
}
/* close connection */
mysqli_close($link);
?>

The above examples will output: 

Array
(
 [0] => Array
 (
 [errno] => 1146
 [sqlstate] => 42S02
 [error] => Table 'world.myCountry' doesn't exist
 )
)

See Also

mysqli_stmt_error
mysqli_stmt_errno
mysqli_stmt_sqlstate
mysqli_stmt::$error, mysqli_stmt_error

Description

Object oriented stylestring mysqli_stmt->error ;

Procedural stylestring mysqli_stmt_error(mysqli_stmt stmt);

Returns a containing the error message for the most recently invoked statement function that can succeed or fail.

Parameters

stmt

Procedural style only: A statement identifier returned by mysqli_stmt_init.

Return Values

A string that describes the error. An empty string if no error occurred.

Examples

Example 20.154. Object oriented style

<?php
/* Open a connection */
$mysqli = new mysqli('localhost', 'my_user', 'my_password', 'world');
/* check connection */
if (mysqli_connect_errno()) {
 printf('Connect failed: %s\n', mysqli_connect_error());
 exit();
}
$mysqli->query('CREATE TABLE myCountry LIKE Country');
$mysqli->query('INSERT INTO myCountry SELECT * FROM Country');
$query = 'SELECT Name, Code FROM myCountry ORDER BY Name';
if ($stmt = $mysqli->prepare($query)) {
 /* drop table */
 $mysqli->query('DROP TABLE myCountry');
 /* execute query */
 $stmt->execute();
 printf('Error: %s.\n', $stmt->error);
 /* close statement */
 $stmt->close();
}
/* close connection */
$mysqli->close();
?>

Example 20.155. Procedural style

<?php
/* Open a connection */
$link = mysqli_connect('localhost', 'my_user', 'my_password', 'world');
/* check connection */
if (mysqli_connect_errno()) {
 printf('Connect failed: %s\n', mysqli_connect_error());
 exit();
}
mysqli_query($link, 'CREATE TABLE myCountry LIKE Country');
mysqli_query($link, 'INSERT INTO myCountry SELECT * FROM Country');
$query = 'SELECT Name, Code FROM myCountry ORDER BY Name';
if ($stmt = mysqli_prepare($link, $query)) {
 /* drop table */
 mysqli_query($link, 'DROP TABLE myCountry');
 /* execute query */
 mysqli_stmt_execute($stmt);
 printf('Error: %s.\n', mysqli_stmt_error($stmt));
 /* close statement */
 mysqli_stmt_close($stmt);
}
/* close connection */
mysqli_close($link);
?>

The above examples will output: 

Error: Table 'world.myCountry' doesn't exist.

See Also

mysqli_stmt_errno
mysqli_stmt_sqlstate
mysqli_stmt::execute, mysqli_stmt_execute

Description

Object oriented stylebool mysqli_stmt::execute();

Procedural stylebool mysqli_stmt_execute(mysqli_stmt stmt);

Executes a query that has been previously prepared using the mysqli_prepare function. When executed any parameter markers which exist will automatically be replaced with the appropriate data.

If the statement is UPDATE, DELETE, or INSERT, the total number of affected rows can be determined by using the mysqli_stmt_affected_rows function. Likewise, if the query yields a result set the mysqli_stmt_fetch function is used.Note

When using mysqli_stmt_execute, the mysqli_stmt_fetch function must be used to fetch the data prior to performing any additional queries.

Parameters

stmt

Procedural style only: A statement identifier returned by mysqli_stmt_init.

Return Values

Returns TRUE on success or FALSE on failure.

Examples

Example 20.156. Object oriented style

<?php
$mysqli = new mysqli('localhost', 'my_user', 'my_password', 'world');
/* check connection */
if (mysqli_connect_errno()) {
 printf('Connect failed: %s\n', mysqli_connect_error());
 exit();
}
$mysqli->query('CREATE TABLE myCity LIKE City');
/* Prepare an insert statement */
$query = 'INSERT INTO myCity (Name, CountryCode, District) VALUES (?,?,?)';
$stmt = $mysqli->prepare($query);
$stmt->bind_param('sss', $val1, $val2, $val3);
$val1 = 'Stuttgart';
$val2 = 'DEU';
$val3 = 'Baden-Wuerttemberg';
/* Execute the statement */
$stmt->execute();
$val1 = 'Bordeaux';
$val2 = 'FRA';
$val3 = 'Aquitaine';
/* Execute the statement */
$stmt->execute();
/* close statement */
$stmt->close();
/* retrieve all rows from myCity */
$query = 'SELECT Name, CountryCode, District FROM myCity';
if ($result = $mysqli->query($query)) {
 while ($row = $result->fetch_row()) {
 printf('%s (%s,%s)\n', $row[0], $row[1], $row[2]);
 }
 /* free result set */
 $result->close();
}
/* remove table */
$mysqli->query('DROP TABLE myCity');
/* close connection */
$mysqli->close();
?>

Example 20.157. Procedural style

<?php
$link = mysqli_connect('localhost', 'my_user', 'my_password', 'world');
/* check connection */
if (mysqli_connect_errno()) {
 printf('Connect failed: %s\n', mysqli_connect_error());
 exit();
}
mysqli_query($link, 'CREATE TABLE myCity LIKE City');
/* Prepare an insert statement */
$query = 'INSERT INTO myCity (Name, CountryCode, District) VALUES (?,?,?)';
$stmt = mysqli_prepare($link, $query);
mysqli_stmt_bind_param($stmt, 'sss', $val1, $val2, $val3);
$val1 = 'Stuttgart';
$val2 = 'DEU';
$val3 = 'Baden-Wuerttemberg';
/* Execute the statement */
mysqli_stmt_execute($stmt);
$val1 = 'Bordeaux';
$val2 = 'FRA';
$val3 = 'Aquitaine';
/* Execute the statement */
mysqli_stmt_execute($stmt);
/* close statement */
mysqli_stmt_close($stmt);
/* retrieve all rows from myCity */
$query = 'SELECT Name, CountryCode, District FROM myCity';
if ($result = mysqli_query($link, $query)) {
 while ($row = mysqli_fetch_row($result)) {
 printf('%s (%s,%s)\n', $row[0], $row[1], $row[2]);
 }
 /* free result set */
 mysqli_free_result($result);
}
/* remove table */
mysqli_query($link, 'DROP TABLE myCity');
/* close connection */
mysqli_close($link);
?>

The above examples will output: 

Stuttgart (DEU,Baden-Wuerttemberg)
Bordeaux (FRA,Aquitaine)

See Also

mysqli_prepare
mysqli_stmt_bind_param
mysqli_stmt::fetch, mysqli_stmt_fetch

Description

Object oriented stylebool mysqli_stmt::fetch();

Procedural stylebool mysqli_stmt_fetch(mysqli_stmt stmt);

Fetch the result from a prepared statement into the variables bound by mysqli_stmt_bind_result.Note

Note that all columns must be bound by the application before calling mysqli_stmt_fetch.Note

Data are transferred unbuffered without calling mysqli_stmt_store_result which can decrease performance (but reduces memory cost).

Parameters

stmt

Procedural style only: A statement identifier returned by mysqli_stmt_init.

Return Values

Table 20.19. Return Values

Value Description
TRUE Success. Data has been fetched
FALSE Error occurred
NULL No more rows/data exists or data truncation occurred

Examples

Example 20.158. Object oriented style

<?php
$mysqli = new mysqli('localhost', 'my_user', 'my_password', 'world');
/* check connection */
if (mysqli_connect_errno()) {
 printf('Connect failed: %s\n', mysqli_connect_error());
 exit();
}
$query = 'SELECT Name, CountryCode FROM City ORDER by ID DESC LIMIT 150,5';
if ($stmt = $mysqli->prepare($query)) {
 /* execute statement */
 $stmt->execute();
 /* bind result variables */
 $stmt->bind_result($name, $code);
 /* fetch values */
 while ($stmt->fetch()) {
 printf ('%s (%s)\n', $name, $code);
 }
 /* close statement */
 $stmt->close();
}
/* close connection */
$mysqli->close();
?>

Example 20.159. Procedural style

<?php
$link = mysqli_connect('localhost', 'my_user', 'my_password', 'world');
/* check connection */
if (mysqli_connect_errno()) {
 printf('Connect failed: %s\n', mysqli_connect_error());
 exit();
}
$query = 'SELECT Name, CountryCode FROM City ORDER by ID DESC LIMIT 150,5';
if ($stmt = mysqli_prepare($link, $query)) {
 /* execute statement */
 mysqli_stmt_execute($stmt);
 /* bind result variables */
 mysqli_stmt_bind_result($stmt, $name, $code);
 /* fetch values */
 while (mysqli_stmt_fetch($stmt)) {
 printf ('%s (%s)\n', $name, $code);
 }
 /* close statement */
 mysqli_stmt_close($stmt);
}
/* close connection */
mysqli_close($link);
?>

The above examples will output: 

Rockford (USA)
Tallahassee (USA)
Salinas (USA)
Santa Clarita (USA)
Springfield (USA)

See Also

mysqli_prepare
mysqli_stmt_errno
mysqli_stmt_error
mysqli_stmt_bind_result
mysqli_stmt::$field_count, mysqli_stmt_field_count

Description

Object oriented styleint mysqli_stmt->field_count ;

Procedural styleint mysqli_stmt_field_count(mysqli_stmt stmt); Warning

This function is currently not documented; only its argument list is available.

mysqli_stmt::free_result, mysqli_stmt_free_result

Description

Object oriented stylevoid mysqli_stmt::free_result();

Procedural stylevoid mysqli_stmt_free_result(mysqli_stmt stmt);

Frees the result memory associated with the statement, which was allocated by mysqli_stmt_store_result.

Parameters

stmt

Procedural style only: A statement identifier returned by mysqli_stmt_init.

Return Values

No value is returned.

See Also

mysqli_stmt_store_result
mysqli_stmt::get_result, mysqli_stmt_get_result

Description

Object oriented stylemysqli_result mysqli_stmt::get_result();

Procedural stylemysqli_result mysqli_stmt_get_result(mysqli_stmt stmt);

Call to return a result set from a prepared statement query.

Parameters

stmt

Procedural style only: A statement identifier returned by mysqli_stmt_init.

Return Values

Returns a resultset or FALSE on failure.

MySQL Native Driver Only

Available only with mysqlnd.

Examples

Example 20.160. Object oriented style

<?php 
$mysqli = new mysqli('127.0.0.1', 'user', 'password', 'world'); 
if($mysqli->connect_error)
{
 die('$mysqli->connect_errno: $myslqi->connect_error');
}
$query = 'SELECT Name, Population, Continent FROM Country WHERE Continent=? ORDER BY Name LIMIT 1';
$stmt = $mysqli->stmt_init();
if(!$stmt->prepare($query))
{
 print 'Failed to prepare statement\n';
}
else
{
 $stmt->bind_param('s', $continent);
 $continent_array = array('Europe','Africa','Asia','North America');
 foreach($continent_array as $continent)
 {
 $stmt->execute();
 $result = $stmt->get_result();
 while ($row = $result->fetch_array(MYSQLI_NUM))
 {
 foreach ($row as $r)
 {
 print '$r ';
 }
 print '\n';
 }
 }
}
$stmt->close();
$mysqli->close();
?>

Example 20.161. Procedural style

<?php 
$link = mysqli_connect('127.0.0.1', 'user', 'password', 'world'); 
if (!$link)
{
 $error = mysqli_connect_error();
 $errno = mysqli_connect_errno();
 print '$errno: $error\n';
 exit();
}
$query = 'SELECT Name, Population, Continent FROM Country WHERE Continent=? ORDER BY Name LIMIT 1';
$stmt = mysqli_stmt_init($link);
if(!mysqli_stmt_prepare($stmt, $query))
{
 print 'Failed to prepare statement\n';
}
else
{
 mysqli_stmt_bind_param($stmt, 's', $continent);
 $continent_array = array('Europe','Africa','Asia','North America');
 foreach($continent_array as $continent)
 {
 mysqli_stmt_execute($stmt);
 $result = mysqli_stmt_get_result($stmt);
 while ($row = mysqli_fetch_array($result, MYSQLI_NUM))
 {
 foreach ($row as $r)
 {
 print '$r ';
 }
 print '\n';
 }
 }
}
mysqli_stmt_close($stmt);
mysqli_close($link);
?>

The above examples will output: 

Albania 3401200 Europe 
Algeria 31471000 Africa 
Afghanistan 22720000 Asia 
Anguilla 8000 North America

See Also

mysqli_prepare
mysqli_stmt_result_metadata
mysqli_stmt_fetch
mysqli_fetch_array
mysqli_stmt_store_result
mysqli_stmt::get_warnings, mysqli_stmt_get_warnings

Description

Object oriented styleobject mysqli_stmt::get_warnings(mysqli_stmt stmt);

Procedural styleobject mysqli_stmt_get_warnings(mysqli_stmt stmt); Warning

This function is currently not documented; only its argument list is available.

mysqli_stmt::$insert_id, mysqli_stmt_insert_id

Description

Object oriented styleint mysqli_stmt->insert_id ;

Procedural stylemixed mysqli_stmt_insert_id(mysqli_stmt stmt); Warning

This function is currently not documented; only its argument list is available.

mysqli_stmt::more_results, mysqli_stmt_more_results

Description

Object oriented style (method):public bool mysqli_stmt::more_results();

Procedural style:bool mysqli_stmt_more_results(mysql_stmt stmt);

Checks if there are more query results from a multiple query.

Parameters

stmt

Procedural style only: A statement identifier returned by mysqli_stmt_init.

Return Values

Returns TRUE if more results exist, otherwise FALSE .

See Also

mysqli_stmt::next_result
mysqli::multi_query
mysqli_stmt::next_result, mysqli_stmt_next_result

Description

Object oriented style (method):public bool mysqli_stmt::next_result();

Procedural style:bool mysqli_stmt_next_result(mysql_stmt stmt);

Reads the next result from a multiple query.

Parameters

stmt

Procedural style only: A statement identifier returned by mysqli_stmt_init.

Return Values

Returns TRUE on success or FALSE on failure.

Errors/Exceptions

Emits an E_STRICT level error if a result set does not exist, and suggests using mysqli_stmt::more_results in these cases, before calling mysqli_stmt::next_result.

See Also

mysqli_stmt::more_results
mysqli::multi_query
mysqli_stmt::$num_rows, mysqli_stmt_num_rows

Description

Object oriented styleint mysqli_stmt->num_rows ;

Procedural styleint mysqli_stmt_num_rows(mysqli_stmt stmt);

Returns the number of rows in the result set. The use of mysqli_stmt_num_rows depends on whether or not you used mysqli_stmt_store_result to buffer the entire result set in the statement handle.

If you use mysqli_stmt_store_result, mysqli_stmt_num_rows may be called immediately.

Parameters

stmt

Procedural style only: A statement identifier returned by mysqli_stmt_init.

Return Values

An integer representing the number of rows in result set.

Examples

Example 20.162. Object oriented style

<?php
/* Open a connection */
$mysqli = new mysqli('localhost', 'my_user', 'my_password', 'world');
/* check connection */
if (mysqli_connect_errno()) {
 printf('Connect failed: %s\n', mysqli_connect_error());
 exit();
}
$query = 'SELECT Name, CountryCode FROM City ORDER BY Name LIMIT 20';
if ($stmt = $mysqli->prepare($query)) {
 /* execute query */
 $stmt->execute();
 /* store result */
 $stmt->store_result();
 printf('Number of rows: %d.\n', $stmt->num_rows);
 /* close statement */
 $stmt->close();
}
/* close connection */
$mysqli->close();
?>

Example 20.163. Procedural style

<?php
/* Open a connection */
$link = mysqli_connect('localhost', 'my_user', 'my_password', 'world');
/* check connection */
if (mysqli_connect_errno()) {
 printf('Connect failed: %s\n', mysqli_connect_error());
 exit();
}
$query = 'SELECT Name, CountryCode FROM City ORDER BY Name LIMIT 20';
if ($stmt = mysqli_prepare($link, $query)) {
 /* execute query */
 mysqli_stmt_execute($stmt);
 /* store result */
 mysqli_stmt_store_result($stmt);
 printf('Number of rows: %d.\n', mysqli_stmt_num_rows($stmt));
 /* close statement */
 mysqli_stmt_close($stmt);
}
/* close connection */
mysqli_close($link);
?>

The above examples will output: 

Number of rows: 20.

See Also

mysqli_stmt_affected_rows
mysqli_prepare
mysqli_stmt_store_result
mysqli_stmt::$param_count, mysqli_stmt_param_count

Description

Object oriented styleint mysqli_stmt->param_count ;

Procedural styleint mysqli_stmt_param_count(mysqli_stmt stmt);

Returns the number of parameter markers present in the prepared statement.

Parameters

stmt

Procedural style only: A statement identifier returned by mysqli_stmt_init.

Return Values

Returns an integer representing the number of parameters.

Examples

Example 20.164. Object oriented style

<?php
$mysqli = new mysqli('localhost', 'my_user', 'my_password', 'world');
/* check connection */
if (mysqli_connect_errno()) {
 printf('Connect failed: %s\n', mysqli_connect_error());
 exit();
}
if ($stmt = $mysqli->prepare('SELECT Name FROM Country WHERE Name=? OR Code=?')) {
 $marker = $stmt->param_count;
 printf('Statement has %d markers.\n', $marker);
 /* close statement */
 $stmt->close();
}
/* close connection */
$mysqli->close();
?>

Example 20.165. Procedural style

<?php
$link = mysqli_connect('localhost', 'my_user', 'my_password', 'world');
/* check connection */
if (mysqli_connect_errno()) {
 printf('Connect failed: %s\n', mysqli_connect_error());
 exit();
}
if ($stmt = mysqli_prepare($link, 'SELECT Name FROM Country WHERE Name=? OR Code=?')) {
 $marker = mysqli_stmt_param_count($stmt);
 printf('Statement has %d markers.\n', $marker);
 /* close statement */
 mysqli_stmt_close($stmt);
}
/* close connection */
mysqli_close($link);
?>

The above examples will output: 

Statement has 2 markers.

See Also

mysqli_prepare
mysqli_stmt::prepare, mysqli_stmt_prepare

Description

Object oriented stylemixed mysqli_stmt::prepare(string query);

Procedural stylebool mysqli_stmt_prepare(mysqli_stmt stmt,
string query);

Prepares the SQL query pointed to by the null-terminated string query.

The parameter markers must be bound to application variables using mysqli_stmt_bind_param and/or mysqli_stmt_bind_result before executing the statement or fetching rows.Note

In the case where you pass a statement to mysqli_stmt_prepare that is longer than max_allowed_packet of the server, the returned error codes are different depending on whether you are using MariaDB Native Driver (mysqlnd) or MariaDB Client Library (libmysql). The behavior is as follows:

Parameters

stmt

Procedural style only: A statement identifier returned by mysqli_stmt_init.

query

The query, as a string. It must consist of a single SQL statement.

You can include one or more parameter markers in the SQL statement by embedding question mark (?) characters at the appropriate positions.Note

You should not add a terminating semicolon or \g to the statement.Note

The markers are legal only in certain places in SQL statements. For example, they are allowed in the VALUES() list of an INSERT statement (to specify column values for a row), or in a comparison with a column in a WHERE clause to specify a comparison value.

However, they are not allowed for identifiers (such as table or column names), in the select list that names the columns to be returned by a SELECT statement), or to specify both operands of a binary operator such as the = equal sign. The latter restriction is necessary because it would be impossible to determine the parameter type. In general, parameters are legal only in Data Manipulation Language (DML) statements, and not in Data Definition Language (DDL) statements.

Return Values

Returns TRUE on success or FALSE on failure.

Examples

Example 20.166. Object oriented style

<?php
$mysqli = new mysqli('localhost', 'my_user', 'my_password', 'world');
/* check connection */
if (mysqli_connect_errno()) {
 printf('Connect failed: %s\n', mysqli_connect_error());
 exit();
}
$city = 'Amersfoort';
/* create a prepared statement */
$stmt = $mysqli->stmt_init();
if ($stmt->prepare('SELECT District FROM City WHERE Name=?')) {
 /* bind parameters for markers */
 $stmt->bind_param('s', $city);
 /* execute query */
 $stmt->execute();
 /* bind result variables */
 $stmt->bind_result($district);
 /* fetch value */
 $stmt->fetch();
 printf('%s is in district %s\n', $city, $district);
 /* close statement */
 $stmt->close();
}
/* close connection */
$mysqli->close();
?>

Example 20.167. Procedural style

<?php
$link = mysqli_connect('localhost', 'my_user', 'my_password', 'world');
/* check connection */
if (mysqli_connect_errno()) {
 printf('Connect failed: %s\n', mysqli_connect_error());
 exit();
}
$city = 'Amersfoort';
/* create a prepared statement */
$stmt = mysqli_stmt_init($link);
if (mysqli_stmt_prepare($stmt, 'SELECT District FROM City WHERE Name=?')) {
 /* bind parameters for markers */
 mysqli_stmt_bind_param($stmt, 's', $city);
 /* execute query */
 mysqli_stmt_execute($stmt);
 /* bind result variables */
 mysqli_stmt_bind_result($stmt, $district);
 /* fetch value */
 mysqli_stmt_fetch($stmt);
 printf('%s is in district %s\n', $city, $district);
 /* close statement */
 mysqli_stmt_close($stmt);
}
/* close connection */
mysqli_close($link);
?>

The above examples will output: 

Amersfoort is in district Utrecht

See Also

mysqli_stmt_init
mysqli_stmt_execute
mysqli_stmt_fetch
mysqli_stmt_bind_param
mysqli_stmt_bind_result
mysqli_stmt_close
mysqli_stmt::reset, mysqli_stmt_reset

Description

Object oriented stylebool mysqli_stmt::reset();

Procedural stylebool mysqli_stmt_reset(mysqli_stmt stmt);

Resets a prepared statement on client and server to state after prepare.

It resets the statement on the server, data sent using mysqli_stmt_send_long_data, unbuffered result sets and current errors. It does not clear bindings or stored result sets. Stored result sets will be cleared when executing the prepared statement (or closing it).

To prepare a statement with another query use function mysqli_stmt_prepare.

Parameters

stmt

Procedural style only: A statement identifier returned by mysqli_stmt_init.

Return Values

Returns TRUE on success or FALSE on failure.

See Also

mysqli_prepare
mysqli_stmt::result_metadata, mysqli_stmt_result_metadata

Description

Object oriented stylemysqli_result mysqli_stmt::result_metadata();

Procedural stylemysqli_result mysqli_stmt_result_metadata(mysqli_stmt stmt);

If a statement passed to mysqli_prepare is one that produces a result set, mysqli_stmt_result_metadata returns the result object that can be used to process the meta information such as total number of fields and individual field information.Note

This result set pointer can be passed as an argument to any of the field-based functions that process result set metadata, such as:

The result set structure should be freed when you are done with it, which you can do by passing it to mysqli_free_resultNote

The result set returned by mysqli_stmt_result_metadata contains only metadata. It does not contain any row results. The rows are obtained by using the statement handle with mysqli_stmt_fetch.

Parameters

stmt

Procedural style only: A statement identifier returned by mysqli_stmt_init.

Return Values

Returns a result object or FALSE if an error occurred.

Examples

Example 20.168. Object oriented style

<?php
$mysqli = new mysqli('localhost', 'my_user', 'my_password', 'test');
$mysqli->query('DROP TABLE IF EXISTS friends');
$mysqli->query('CREATE TABLE friends (id int, name varchar(20))');
$mysqli->query('INSERT INTO friends VALUES (1,'Hartmut'), (2, 'Ulf')');
$stmt = $mysqli->prepare('SELECT id, name FROM friends');
$stmt->execute();
/* get resultset for metadata */
$result = $stmt->result_metadata();
/* retrieve field information from metadata result set */
$field = $result->fetch_field();
printf('Fieldname: %s\n', $field->name);
/* close resultset */
$result->close();
/* close connection */
$mysqli->close();
?>

Example 20.169. Procedural style

<?php
$link = mysqli_connect('localhost', 'my_user', 'my_password', 'test');
mysqli_query($link, 'DROP TABLE IF EXISTS friends');
mysqli_query($link, 'CREATE TABLE friends (id int, name varchar(20))');
mysqli_query($link, 'INSERT INTO friends VALUES (1,'Hartmut'), (2, 'Ulf')');
$stmt = mysqli_prepare($link, 'SELECT id, name FROM friends');
mysqli_stmt_execute($stmt);
/* get resultset for metadata */
$result = mysqli_stmt_result_metadata($stmt);
/* retrieve field information from metadata result set */
$field = mysqli_fetch_field($result);
printf('Fieldname: %s\n', $field->name);
/* close resultset */
mysqli_free_result($result);
/* close connection */
mysqli_close($link);
?>

See Also

mysqli_prepare
mysqli_free_result
mysqli_stmt::send_long_data, mysqli_stmt_send_long_data

Description

Object oriented stylebool mysqli_stmt::send_long_data(int param_nr,
string data);

Procedural stylebool mysqli_stmt_send_long_data(mysqli_stmt stmt,
int param_nr,
string data);

Allows to send parameter data to the server in pieces (or chunks), e.g. if the size of a blob exceeds the size of max_allowed_packet. This function can be called multiple times to send the parts of a character or binary data value for a column, which must be one of the TEXT or BLOB datatypes.

Parameters

stmt

Procedural style only: A statement identifier returned by mysqli_stmt_init.

param_nr

Indicates which parameter to associate the data with. Parameters are numbered beginning with 0.

data

A string containing data to be sent.

Return Values

Returns TRUE on success or FALSE on failure.

Examples

Example 20.170. Object oriented style

<?php
$stmt = $mysqli->prepare('INSERT INTO messages (message) VALUES (?)');
$null = NULL;
$stmt->bind_param('b', $null);
$fp = fopen('messages.txt', 'r');
while (!feof($fp)) {
 $stmt->send_long_data(0, fread($fp, 8192));
}
fclose($fp);
$stmt->execute();
?>

See Also

mysqli_prepare
mysqli_stmt_bind_param
mysqli_stmt::$sqlstate, mysqli_stmt_sqlstate

Description

Object oriented stylestring mysqli_stmt->sqlstate ;

Procedural stylestring mysqli_stmt_sqlstate(mysqli_stmt stmt);

Returns a string containing the SQLSTATE error code for the most recently invoked prepared statement function that can succeed or fail. The error code consists of five characters. '00000' means no error. The values are specified by ANSI SQL and ODBC. For a list of possible values, see http://dev.mysql.com/doc/mysql/en/error-handling.html.

Parameters

stmt

Procedural style only: A statement identifier returned by mysqli_stmt_init.

Return Values

Returns a string containing the SQLSTATE error code for the last error. The error code consists of five characters. '00000' means no error.

Notes

Note

Note that not all MariaDB errors are yet mapped to SQLSTATE's. The value HY000 (general error) is used for unmapped errors.

Examples

Example 20.171. Object oriented style

<?php
/* Open a connection */
$mysqli = new mysqli('localhost', 'my_user', 'my_password', 'world');
/* check connection */
if (mysqli_connect_errno()) {
 printf('Connect failed: %s\n', mysqli_connect_error());
 exit();
}
$mysqli->query('CREATE TABLE myCountry LIKE Country');
$mysqli->query('INSERT INTO myCountry SELECT * FROM Country');
$query = 'SELECT Name, Code FROM myCountry ORDER BY Name';
if ($stmt = $mysqli->prepare($query)) {
 /* drop table */
 $mysqli->query('DROP TABLE myCountry');
 /* execute query */
 $stmt->execute();
 printf('Error: %s.\n', $stmt->sqlstate);
 /* close statement */
 $stmt->close();
}
/* close connection */
$mysqli->close();
?>

Example 20.172. Procedural style

<?php
/* Open a connection */
$link = mysqli_connect('localhost', 'my_user', 'my_password', 'world');
/* check connection */
if (mysqli_connect_errno()) {
 printf('Connect failed: %s\n', mysqli_connect_error());
 exit();
}
mysqli_query($link, 'CREATE TABLE myCountry LIKE Country');
mysqli_query($link, 'INSERT INTO myCountry SELECT * FROM Country');
$query = 'SELECT Name, Code FROM myCountry ORDER BY Name';
if ($stmt = mysqli_prepare($link, $query)) {
 /* drop table */
 mysqli_query($link, 'DROP TABLE myCountry');
 /* execute query */
 mysqli_stmt_execute($stmt);
 printf('Error: %s.\n', mysqli_stmt_sqlstate($stmt));
 /* close statement */
 mysqli_stmt_close($stmt);
}
/* close connection */
mysqli_close($link);
?>

The above examples will output: 

Error: 42S02.

See Also

mysqli_stmt_errno
mysqli_stmt_error
mysqli_stmt::store_result, mysqli_stmt_store_result

Description

Object oriented stylebool mysqli_stmt::store_result();

Procedural stylebool mysqli_stmt_store_result(mysqli_stmt stmt);

You must call mysqli_stmt_store_result for every query that successfully produces a result set (SELECT, SHOW, DESCRIBE, EXPLAIN), and only if you want to buffer the complete result set by the client, so that the subsequent mysqli_stmt_fetch call returns buffered data.Note

It is unnecessary to call mysqli_stmt_store_result for other queries, but if you do, it will not harm or cause any notable performance in all cases. You can detect whether the query produced a result set by checking if mysqli_stmt_result_metadata returns NULL.

Parameters

stmt

Procedural style only: A statement identifier returned by mysqli_stmt_init.

Return Values

Returns TRUE on success or FALSE on failure.

Examples

Example 20.173. Object oriented style

<?php
/* Open a connection */
$mysqli = new mysqli('localhost', 'my_user', 'my_password', 'world');
/* check connection */
if (mysqli_connect_errno()) {
 printf('Connect failed: %s\n', mysqli_connect_error());
 exit();
}
$query = 'SELECT Name, CountryCode FROM City ORDER BY Name LIMIT 20';
if ($stmt = $mysqli->prepare($query)) {
 /* execute query */
 $stmt->execute();
 /* store result */
 $stmt->store_result();
 printf('Number of rows: %d.\n', $stmt->num_rows);
 /* free result */
 $stmt->free_result();
 /* close statement */
 $stmt->close();
}
/* close connection */
$mysqli->close();
?>

Example 20.174. Procedural style

<?php
/* Open a connection */
$link = mysqli_connect('localhost', 'my_user', 'my_password', 'world');
/* check connection */
if (mysqli_connect_errno()) {
 printf('Connect failed: %s\n', mysqli_connect_error());
 exit();
}
$query = 'SELECT Name, CountryCode FROM City ORDER BY Name LIMIT 20';
if ($stmt = mysqli_prepare($link, $query)) {
 /* execute query */
 mysqli_stmt_execute($stmt);
 /* store result */
 mysqli_stmt_store_result($stmt);
 printf('Number of rows: %d.\n', mysqli_stmt_num_rows($stmt));
 /* free result */
 mysqli_stmt_free_result($stmt);
 /* close statement */
 mysqli_stmt_close($stmt);
}
/* close connection */
mysqli_close($link);
?>

The above examples will output: 

Number of rows: 20.

See Also

mysqli_prepare
mysqli_stmt_result_metadata
mysqli_stmt_fetch

The mysqli_result class (mysqli_result)

mysqli_result::$current_field, mysqli_field_tell
mysqli_result::data_seek, mysqli_data_seek
mysqli_result::fetch_all, mysqli_fetch_all
mysqli_result::fetch_array, mysqli_fetch_array
mysqli_result::fetch_assoc, mysqli_fetch_assoc
mysqli_result::fetch_field_direct, mysqli_fetch_field_direct
mysqli_result::fetch_field, mysqli_fetch_field
mysqli_result::fetch_fields, mysqli_fetch_fields
mysqli_result::fetch_object, mysqli_fetch_object
mysqli_result::fetch_row, mysqli_fetch_row
mysqli_result::$field_count, mysqli_num_fields
mysqli_result::field_seek, mysqli_field_seek
mysqli_result::free, mysqli_free_result
mysqli_result::$lengths, mysqli_fetch_lengths
mysqli_result::$num_rows, mysqli_num_rows

Represents the result set obtained from a query against the database.

Changelog

Table 20.20. Changelog

Version Description
5.4.0 Iterator support was added, as mysqli_result now implements Traversable.
 mysqli_result {

 mysqli_result
 , Traversable
 Properties int mysqli_result->current_field ;

 int mysqli_result->field_count ;

 array mysqli_result->lengths ;

 int mysqli_result->num_rows ;

Methods bool mysqli_result::data_seek(int offset);

 mixed mysqli_result::fetch_all(int resulttype= =MYSQLI_NUM);

 mixed mysqli_result::fetch_array(int resulttype= =MYSQLI_BOTH);

 array mysqli_result::fetch_assoc();

 object mysqli_result::fetch_field_direct(int fieldnr);

 object mysqli_result::fetch_field();

 array mysqli_result::fetch_fields();

 object mysqli_result::fetch_object(string class_name,

 array params);

 mixed mysqli_result::fetch_row();

 bool mysqli_result::field_seek(int fieldnr);

 void mysqli_result::free();

}
mysqli_result::$current_field, mysqli_field_tell

Description

Object oriented styleint mysqli_result->current_field ;

Procedural styleint mysqli_field_tell(mysqli_result result);

Returns the position of the field cursor used for the last mysqli_fetch_field call. This value can be used as an argument to mysqli_field_seek.

Parameters

result

Procedural style only: A result set identifier returned by mysqli_query, mysqli_store_result or mysqli_use_result.

Return Values

Returns current offset of field cursor.

Examples

Example 20.175. Object oriented style

<?php
$mysqli = new mysqli('localhost', 'my_user', 'my_password', 'world');
/* check connection */
if (mysqli_connect_errno()) {
 printf('Connect failed: %s\n', mysqli_connect_error());
 exit();
}
$query = 'SELECT Name, SurfaceArea from Country ORDER BY Code LIMIT 5';
if ($result = $mysqli->query($query)) {
 /* Get field information for all columns */
 while ($finfo = $result->fetch_field()) {
 /* get fieldpointer offset */
 $currentfield = $result->current_field;
 printf('Column %d:\n', $currentfield);
 printf('Name: %s\n', $finfo->name);
 printf('Table: %s\n', $finfo->table);
 printf('max. Len: %d\n', $finfo->max_length);
 printf('Flags: %d\n', $finfo->flags);
 printf('Type: %d\n\n', $finfo->type);
 }
 $result->close();
}
/* close connection */
$mysqli->close();
?>

Example 20.176. Procedural style

<?php
$link = mysqli_connect('localhost', 'my_user', 'my_password', 'world');
/* check connection */
if (mysqli_connect_errno()) {
 printf('Connect failed: %s\n', mysqli_connect_error());
 exit();
}
$query = 'SELECT Name, SurfaceArea from Country ORDER BY Code LIMIT 5';
if ($result = mysqli_query($link, $query)) {
 /* Get field information for all fields */
 while ($finfo = mysqli_fetch_field($result)) {
 /* get fieldpointer offset */
 $currentfield = mysqli_field_tell($result);
 printf('Column %d:\n', $currentfield);
 printf('Name: %s\n', $finfo->name);
 printf('Table: %s\n', $finfo->table);
 printf('max. Len: %d\n', $finfo->max_length);
 printf('Flags: %d\n', $finfo->flags);
 printf('Type: %d\n\n', $finfo->type);
 }
 mysqli_free_result($result);
}
/* close connection */
mysqli_close($link);
?>

The above examples will output: 

Column 1:
Name: Name Table: Country max. Len: 11
Flags: 1
Type: 254
Column 2:
Name: SurfaceArea Table: Country max. Len: 10
Flags: 32769
Type: 4

See Also

mysqli_fetch_field
mysqli_field_seek
mysqli_result::data_seek, mysqli_data_seek

Description

Object oriented stylebool mysqli_result::data_seek(int offset);

Procedural stylebool mysqli_data_seek(mysqli_result result,
int offset);

The mysqli_data_seek function seeks to an arbitrary result pointer specified by the offset in the result set.

Parameters

result

Procedural style only: A result set identifier returned by mysqli_query, mysqli_store_result or mysqli_use_result.

offset

The field offset. Must be between zero and the total number of rows minus one (0..mysqli_num_rows - 1).

Return Values

Returns TRUE on success or FALSE on failure.

Notes

Note

This function can only be used with buffered results attained from the use of the mysqli_store_result or mysqli_query functions.

Examples

Example 20.177. Object oriented style

<?php
/* Open a connection */
$mysqli = new mysqli('localhost', 'my_user', 'my_password', 'world');
/* check connection */
if (mysqli_connect_errno()) {
 printf('Connect failed: %s\n', mysqli_connect_error());
 exit();
}
$query = 'SELECT Name, CountryCode FROM City ORDER BY Name';
if ($result = $mysqli->query( $query)) {
 /* seek to row no. 400 */
 $result->data_seek(399);
 /* fetch row */
 $row = $result->fetch_row();
 printf ('City: %s Countrycode: %s\n', $row[0], $row[1]);
 /* free result set*/
 $result->close();
}
/* close connection */
$mysqli->close();
?>

Example 20.178. Procedural style

<?php
/* Open a connection */
$link = mysqli_connect('localhost', 'my_user', 'my_password', 'world');
/* check connection */
if (!$link) {
 printf('Connect failed: %s\n', mysqli_connect_error());
 exit();
}
$query = 'SELECT Name, CountryCode FROM City ORDER BY Name';
if ($result = mysqli_query($link, $query)) {
 /* seek to row no. 400 */
 mysqli_data_seek($result, 399);
 /* fetch row */
 $row = mysqli_fetch_row($result);
 printf ('City: %s Countrycode: %s\n', $row[0], $row[1]);
 /* free result set*/
 mysqli_free_result($result);
}
/* close connection */
mysqli_close($link);
?>

The above examples will output: 

City: Benin City Countrycode: NGA

See Also

mysqli_store_result
mysqli_fetch_row
mysqli_fetch_array
mysqli_fetch_assoc
mysqli_fetch_object
mysqli_query
mysqli_num_rows
mysqli_result::fetch_all, mysqli_fetch_all

Description

Object oriented stylemixed mysqli_result::fetch_all(int resulttype= =MYSQLI_NUM);

Procedural stylemixed mysqli_fetch_all(mysqli_result result,
int resulttype= =MYSQLI_NUM);

mysqli_fetch_all fetches all result rows and returns the result set as an associative array, a numeric array, or both.

Parameters

result

Procedural style only: A result set identifier returned by mysqli_query, mysqli_store_result or mysqli_use_result.

resulttype

This optional parameter is a constant indicating what type of array should be produced from the current row data. The possible values for this parameter are the constants MYSQLI_ASSOC , MYSQLI_NUM , or MYSQLI_BOTH .

Return Values

Returns an array of associative or numeric arrays holding result rows.

MySQL Native Driver Only

Available only with mysqlnd.

As mysqli_fetch_all returns all the rows as an array in a single step, it may consume more memory than some similar functions such as mysqli_fetch_array, which only returns one row at a time from the result set. Further, if you need to iterate over the result set, you will need a looping construct that will further impact performance. For these reasons mysqli_fetch_all should only be used in those situations where the fetched result set will be sent to another layer for processing.

See Also

mysqli_fetch_array
mysqli_query
mysqli_result::fetch_array, mysqli_fetch_array

Description

Object oriented stylemixed mysqli_result::fetch_array(int resulttype= =MYSQLI_BOTH);

Procedural stylemixed mysqli_fetch_array(mysqli_result result,
int resulttype= =MYSQLI_BOTH);

Returns an array that corresponds to the fetched row or NULL if there are no more rows for the resultset represented by the result parameter.

mysqli_fetch_array is an extended version of the mysqli_fetch_row function. In addition to storing the data in the numeric indices of the result array, the mysqli_fetch_array function can also store the data in associative indices, using the field names of the result set as keys.Note

Field names returned by this function are case-sensitive.Note

This function sets NULL fields to the PHP NULL value.

If two or more columns of the result have the same field names, the last column will take precedence and overwrite the earlier data. In order to access multiple columns with the same name, the numerically indexed version of the row must be used.

Parameters

result

Procedural style only: A result set identifier returned by mysqli_query, mysqli_store_result or mysqli_use_result.

resulttype

This optional parameter is a constant indicating what type of array should be produced from the current row data. The possible values for this parameter are the constants MYSQLI_ASSOC , MYSQLI_NUM , or MYSQLI_BOTH .

By using the MYSQLI_ASSOC constant this function will behave identically to the mysqli_fetch_assoc, while MYSQLI_NUM will behave identically to the mysqli_fetch_row function. The final option MYSQLI_BOTH will create a single array with the attributes of both.

Return Values

Returns an array of strings that corresponds to the fetched row or NULL if there are no more rows in resultset.

Examples

Example 20.179. Object oriented style

<?php
$mysqli = new mysqli('localhost', 'my_user', 'my_password', 'world');
/* check connection */
if (mysqli_connect_errno()) {
 printf('Connect failed: %s\n', mysqli_connect_error());
 exit();
}
$query = 'SELECT Name, CountryCode FROM City ORDER by ID LIMIT 3';
$result = $mysqli->query($query);
/* numeric array */
$row = $result->fetch_array(MYSQLI_NUM);
printf ('%s (%s)\n', $row[0], $row[1]);
/* associative array */
$row = $result->fetch_array(MYSQLI_ASSOC);
printf ('%s (%s)\n', $row['Name'], $row['CountryCode']);
/* associative and numeric array */
$row = $result->fetch_array(MYSQLI_BOTH);
printf ('%s (%s)\n', $row[0], $row['CountryCode']);
/* free result set */
$result->close();
/* close connection */
$mysqli->close();
?>

Example 20.180. Procedural style

<?php
$link = mysqli_connect('localhost', 'my_user', 'my_password', 'world');
/* check connection */
if (mysqli_connect_errno()) {
 printf('Connect failed: %s\n', mysqli_connect_error());
 exit();
}
$query = 'SELECT Name, CountryCode FROM City ORDER by ID LIMIT 3';
$result = mysqli_query($link, $query);
/* numeric array */
$row = mysqli_fetch_array($result, MYSQLI_NUM);
printf ('%s (%s)\n', $row[0], $row[1]);
/* associative array */
$row = mysqli_fetch_array($result, MYSQLI_ASSOC);
printf ('%s (%s)\n', $row['Name'], $row['CountryCode']);
/* associative and numeric array */
$row = mysqli_fetch_array($result, MYSQLI_BOTH);
printf ('%s (%s)\n', $row[0], $row['CountryCode']);
/* free result set */
mysqli_free_result($result);
/* close connection */
mysqli_close($link);
?>

The above examples will output: 

Kabul (AFG)
Qandahar (AFG)
Herat (AFG)

See Also

mysqli_fetch_assoc
mysqli_fetch_row
mysqli_fetch_object
mysqli_query
mysqli_data_seek
mysqli_result::fetch_assoc, mysqli_fetch_assoc

Description

Object oriented stylearray mysqli_result::fetch_assoc();

Procedural stylearray mysqli_fetch_assoc(mysqli_result result);

Returns an associative array that corresponds to the fetched row or NULL if there are no more rows.Note

Field names returned by this function are case-sensitive.Note

This function sets NULL fields to the PHP NULL value.

Parameters

result

Procedural style only: A result set identifier returned by mysqli_query, mysqli_store_result or mysqli_use_result.

Return Values

Returns an associative array of strings representing the fetched row in the result set, where each key in the array represents the name of one of the result set's columns or NULL if there are no more rows in resultset.

If two or more columns of the result have the same field names, the last column will take precedence. To access the other column(s) of the same name, you either need to access the result with numeric indices by using mysqli_fetch_row or add alias names.

Examples

Example 20.181. Object oriented style

<?php
$mysqli = new mysqli('localhost', 'my_user', 'my_password', 'world');
/* check connection */
if (mysqli_connect_errno()) {
 printf('Connect failed: %s\n', mysqli_connect_error());
 exit();
}
$query = 'SELECT Name, CountryCode FROM City ORDER by ID DESC LIMIT 50,5';
if ($result = $mysqli->query($query)) {
 /* fetch associative array */
 while ($row = $result->fetch_assoc()) {
 printf ('%s (%s)\n', $row['Name'], $row['CountryCode']);
 }
 /* free result set */
 $result->free();
}
/* close connection */
$mysqli->close();
?>

Example 20.182. Procedural style

<?php
$link = mysqli_connect('localhost', 'my_user', 'my_password', 'world');
/* check connection */
if (mysqli_connect_errno()) {
 printf('Connect failed: %s\n', mysqli_connect_error());
 exit();
}
$query = 'SELECT Name, CountryCode FROM City ORDER by ID DESC LIMIT 50,5';
if ($result = mysqli_query($link, $query)) {
 /* fetch associative array */
 while ($row = mysqli_fetch_assoc($result)) {
 printf ('%s (%s)\n', $row['Name'], $row['CountryCode']);
 }
 /* free result set */
 mysqli_free_result($result);
}
/* close connection */
mysqli_close($link);
?>

The above examples will output: 

Pueblo (USA)
Arvada (USA)
Cape Coral (USA)
Green Bay (USA)
Santa Clara (USA)

Example 20.183. A mysqli_result example comparing iterator usage 

<?php
$c = mysqli_connect('127.0.0.1','user', 'pass');
// Using iterators (support was added with PHP 5.4)
foreach ( $c->query('SELECT user,host FROM mysql.user') as $row ) {
 printf(''%s'@'%s'\n', $row['user'], $row['host']);
}
echo '\n==================\n';
// Not using iterators
$result = $c->query('SELECT user,host FROM mysql.user');
while ($row = $result->fetch_assoc()) {
 printf(''%s'@'%s'\n', $row['user'], $row['host']);
}
?>

The above example will output something similar to: 

'root'@'192.168.1.1'
'root'@'127.0.0.1'
'dude'@'localhost'
'lebowski'@'localhost'
==================
'root'@'192.168.1.1'
'root'@'127.0.0.1'
'dude'@'localhost'
'lebowski'@'localhost'

See Also

mysqli_fetch_array
mysqli_fetch_row
mysqli_fetch_object
mysqli_query
mysqli_data_seek
mysqli_result::fetch_field_direct, mysqli_fetch_field_direct

Description

Object oriented styleobject mysqli_result::fetch_field_direct(int fieldnr);

Procedural styleobject mysqli_fetch_field_direct(mysqli_result result,
int fieldnr);

Returns an object which contains field definition information from the specified result set.

Parameters

result

Procedural style only: A result set identifier returned by mysqli_query, mysqli_store_result or mysqli_use_result.

fieldnr

The field number. This value must be in the range from 0 to number of fields - 1.

Return Values

Returns an object which contains field definition information or FALSE if no field information for specified fieldnr is available.

Table 20.21. Object attributes

Attribute Description
name The name of the column
orgname Original column name if an alias was specified
table The name of the table this field belongs to (if not calculated)
orgtable Original table name if an alias was specified
def The default value for this field, represented as a string
max_length The maximum width of the field for the result set.
length The width of the field, as specified in the table definition.
charsetnr The character set number for the field.
flags An integer representing the bit-flags for the field.
type The data type used for this field
decimals The number of decimals used (for integer fields)

Examples

Example 20.184. Object oriented style

<?php
$mysqli = new mysqli('localhost', 'my_user', 'my_password', 'world');
/* check connection */
if (mysqli_connect_errno()) {
 printf('Connect failed: %s\n', mysqli_connect_error());
 exit();
}
$query = 'SELECT Name, SurfaceArea from Country ORDER BY Name LIMIT 5';
if ($result = $mysqli->query($query)) {
 /* Get field information for column 'SurfaceArea' */
 $finfo = $result->fetch_field_direct(1);
 printf('Name: %s\n', $finfo->name);
 printf('Table: %s\n', $finfo->table);
 printf('max. Len: %d\n', $finfo->max_length);
 printf('Flags: %d\n', $finfo->flags);
 printf('Type: %d\n', $finfo->type);
 $result->close();
}
/* close connection */
$mysqli->close();
?>

Example 20.185. Procedural style

<?php
$link = mysqli_connect('localhost', 'my_user', 'my_password', 'world');
/* check connection */
if (mysqli_connect_errno()) {
 printf('Connect failed: %s\n', mysqli_connect_error());
 exit();
}
$query = 'SELECT Name, SurfaceArea from Country ORDER BY Name LIMIT 5';
if ($result = mysqli_query($link, $query)) {
 /* Get field information for column 'SurfaceArea' */
 $finfo = mysqli_fetch_field_direct($result, 1);
 printf('Name: %s\n', $finfo->name);
 printf('Table: %s\n', $finfo->table);
 printf('max. Len: %d\n', $finfo->max_length);
 printf('Flags: %d\n', $finfo->flags);
 printf('Type: %d\n', $finfo->type);
 mysqli_free_result($result);
}
/* close connection */
mysqli_close($link);
?>

The above examples will output: 

Name: SurfaceArea Table: Country max. Len: 10
Flags: 32769
Type: 4

See Also

mysqli_num_fields
mysqli_fetch_field
mysqli_fetch_fields
mysqli_result::fetch_field, mysqli_fetch_field

Description

Object oriented styleobject mysqli_result::fetch_field();

Procedural styleobject mysqli_fetch_field(mysqli_result result);

Returns the definition of one column of a result set as an object. Call this function repeatedly to retrieve information about all columns in the result set.

Parameters

result

Procedural style only: A result set identifier returned by mysqli_query, mysqli_store_result or mysqli_use_result.

Return Values

Returns an object which contains field definition information or FALSE if no field information is available.

Table 20.22. Object properties

Property Description
name The name of the column
orgname Original column name if an alias was specified
table The name of the table this field belongs to (if not calculated)
orgtable Original table name if an alias was specified
def Reserved for default value, currently always ''
db Database (since PHP 5.3.6)
catalog The catalog name, always 'def' (since PHP 5.3.6)
max_length The maximum width of the field for the result set.
length The width of the field, as specified in the table definition.
charsetnr The character set number for the field.
flags An integer representing the bit-flags for the field.
type The data type used for this field
decimals The number of decimals used (for integer fields)

Examples

Example 20.186. Object oriented style

<?php
$mysqli = new mysqli('localhost', 'my_user', 'my_password', 'world');
/* check connection */
if (mysqli_connect_errno()) {
 printf('Connect failed: %s\n', mysqli_connect_error());
 exit();
}
$query = 'SELECT Name, SurfaceArea from Country ORDER BY Code LIMIT 5';
if ($result = $mysqli->query($query)) {
 /* Get field information for all columns */
 while ($finfo = $result->fetch_field()) {
 printf('Name: %s\n', $finfo->name);
 printf('Table: %s\n', $finfo->table);
 printf('max. Len: %d\n', $finfo->max_length);
 printf('Flags: %d\n', $finfo->flags);
 printf('Type: %d\n\n', $finfo->type);
 }
 $result->close();
}
/* close connection */
$mysqli->close();
?>

Example 20.187. Procedural style

<?php
$link = mysqli_connect('localhost', 'my_user', 'my_password', 'world');
/* check connection */
if (mysqli_connect_errno()) {
 printf('Connect failed: %s\n', mysqli_connect_error());
 exit();
}
$query = 'SELECT Name, SurfaceArea from Country ORDER BY Code LIMIT 5';
if ($result = mysqli_query($link, $query)) {
 /* Get field information for all fields */
 while ($finfo = mysqli_fetch_field($result)) {
 printf('Name: %s\n', $finfo->name);
 printf('Table: %s\n', $finfo->table);
 printf('max. Len: %d\n', $finfo->max_length);
 printf('Flags: %d\n', $finfo->flags);
 printf('Type: %d\n\n', $finfo->type);
 }
 mysqli_free_result($result);
}
/* close connection */
mysqli_close($link);
?>

The above examples will output: 

Name: Name Table: Country max. Len: 11
Flags: 1
Type: 254
Name: SurfaceArea Table: Country max. Len: 10
Flags: 32769
Type: 4

See Also

mysqli_num_fields
mysqli_fetch_field_direct
mysqli_fetch_fields
mysqli_field_seek
mysqli_result::fetch_fields, mysqli_fetch_fields

Description

Object oriented stylearray mysqli_result::fetch_fields();

Procedural stylearray mysqli_fetch_fields(mysqli_result result);

This function serves an identical purpose to the mysqli_fetch_field function with the single difference that, instead of returning one object at a time for each field, the columns are returned as an array of objects.

Parameters

result

Procedural style only: A result set identifier returned by mysqli_query, mysqli_store_result or mysqli_use_result.

Return Values

Returns an array of objects which contains field definition information or FALSE if no field information is available.

Table 20.23. Object properties

Property Description
name The name of the column
orgname Original column name if an alias was specified
table The name of the table this field belongs to (if not calculated)
orgtable Original table name if an alias was specified
max_length The maximum width of the field for the result set.
length The width of the field, as specified in the table definition.
charsetnr The character set number for the field.
flags An integer representing the bit-flags for the field.
type The data type used for this field
decimals The number of decimals used (for integer fields)

Examples

Example 20.188. Object oriented style

<?php
$mysqli = new mysqli('localhost', 'my_user', 'my_password', 'world');
/* check connection */
if (mysqli_connect_errno()) {
 printf('Connect failed: %s\n', mysqli_connect_error());
 exit();
}
$query = 'SELECT Name, SurfaceArea from Country ORDER BY Code LIMIT 5';
if ($result = $mysqli->query($query)) {
 /* Get field information for all columns */
 $finfo = $result->fetch_fields();
 foreach ($finfo as $val) {
 printf('Name: %s\n', $val->name);
 printf('Table: %s\n', $val->table);
 printf('max. Len: %d\n', $val->max_length);
 printf('Flags: %d\n', $val->flags);
 printf('Type: %d\n\n', $val->type);
 }
 $result->close();
}
/* close connection */
$mysqli->close();
?>

Example 20.189. Procedural style

<?php
$link = mysqli_connect('localhost', 'my_user', 'my_password', 'world');
/* check connection */
if (mysqli_connect_errno()) {
 printf('Connect failed: %s\n', mysqli_connect_error());
 exit();
}
$query = 'SELECT Name, SurfaceArea from Country ORDER BY Code LIMIT 5';
if ($result = mysqli_query($link, $query)) {
 /* Get field information for all columns */
 $finfo = mysqli_fetch_fields($result);
 foreach ($finfo as $val) {
 printf('Name: %s\n', $val->name);
 printf('Table: %s\n', $val->table);
 printf('max. Len: %d\n', $val->max_length);
 printf('Flags: %d\n', $val->flags);
 printf('Type: %d\n\n', $val->type);
 }
 mysqli_free_result($result);
}
/* close connection */
mysqli_close($link);
?>

The above examples will output: 

Name: Name Table: Country max. Len: 11
Flags: 1
Type: 254
Name: SurfaceArea Table: Country max. Len: 10
Flags: 32769
Type: 4

See Also

mysqli_num_fields
mysqli_fetch_field_direct
mysqli_fetch_field
mysqli_result::fetch_object, mysqli_fetch_object

Description

Object oriented styleobject mysqli_result::fetch_object(string class_name,
array params);

Procedural styleobject mysqli_fetch_object(mysqli_result result,
string class_name,
array params);

The mysqli_fetch_object will return the current row result set as an object where the attributes of the object represent the names of the fields found within the result set.

Note that mysqli_fetch_object sets the properties of the object before calling the object constructor.

Parameters

result

Procedural style only: A result set identifier returned by mysqli_query, mysqli_store_result or mysqli_use_result.

class_name

The name of the class to instantiate, set the properties of and return. If not specified, a stdClass object is returned.

params

An optional array of parameters to pass to the constructor for class_name objects.

Return Values

Returns an object with string properties that corresponds to the fetched row or NULL if there are no more rows in resultset.Note

Field names returned by this function are case-sensitive.Note

This function sets NULL fields to the PHP NULL value.

Changelog

Version Description
5.0.0 Added the ability to return as a different object.

Examples

Example 20.190. Object oriented style

<?php
$mysqli = new mysqli('localhost', 'my_user', 'my_password', 'world');
/* check connection */
if (mysqli_connect_errno()) {
 printf('Connect failed: %s\n', mysqli_connect_error());
 exit();
}
$query = 'SELECT Name, CountryCode FROM City ORDER by ID DESC LIMIT 50,5';
if ($result = $mysqli->query($query)) {
 /* fetch object array */
 while ($obj = $result->fetch_object()) {
 printf ('%s (%s)\n', $obj->Name, $obj->CountryCode);
 }
 /* free result set */
 $result->close();
}
/* close connection */
$mysqli->close();
?>

Example 20.191. Procedural style

<?php
$link = mysqli_connect('localhost', 'my_user', 'my_password', 'world');
/* check connection */
if (mysqli_connect_errno()) {
 printf('Connect failed: %s\n', mysqli_connect_error());
 exit();
}
$query = 'SELECT Name, CountryCode FROM City ORDER by ID DESC LIMIT 50,5';
if ($result = mysqli_query($link, $query)) {
 /* fetch associative array */
 while ($obj = mysqli_fetch_object($result)) {
 printf ('%s (%s)\n', $obj->Name, $obj->CountryCode);
 }
 /* free result set */
 mysqli_free_result($result);
}
/* close connection */
mysqli_close($link);
?>

The above examples will output: 

Pueblo (USA)
Arvada (USA)
Cape Coral (USA)
Green Bay (USA)
Santa Clara (USA)

See Also

mysqli_fetch_array
mysqli_fetch_assoc
mysqli_fetch_row
mysqli_query
mysqli_data_seek
mysqli_result::fetch_row, mysqli_fetch_row

Description

Object oriented stylemixed mysqli_result::fetch_row();

Procedural stylemixed mysqli_fetch_row(mysqli_result result);

Fetches one row of data from the result set and returns it as an enumerated array, where each column is stored in an array offset starting from 0 (zero). Each subsequent call to this function will return the next row within the result set, or NULL if there are no more rows.

Parameters

result

Procedural style only: A result set identifier returned by mysqli_query, mysqli_store_result or mysqli_use_result.

Return Values

mysqli_fetch_row returns an array of strings that corresponds to the fetched row or NULL if there are no more rows in result set.Note

This function sets NULL fields to the PHP NULL value.

Examples

Example 20.192. Object oriented style

<?php
$mysqli = new mysqli('localhost', 'my_user', 'my_password', 'world');
/* check connection */
if (mysqli_connect_errno()) {
 printf('Connect failed: %s\n', mysqli_connect_error());
 exit();
}
$query = 'SELECT Name, CountryCode FROM City ORDER by ID DESC LIMIT 50,5';
if ($result = $mysqli->query($query)) {
 /* fetch object array */
 while ($row = $result->fetch_row()) {
 printf ('%s (%s)\n', $row[0], $row[1]);
 }
 /* free result set */
 $result->close();
}
/* close connection */
$mysqli->close();
?>

Example 20.193. Procedural style

<?php
$link = mysqli_connect('localhost', 'my_user', 'my_password', 'world');
/* check connection */
if (mysqli_connect_errno()) {
 printf('Connect failed: %s\n', mysqli_connect_error());
 exit();
}
$query = 'SELECT Name, CountryCode FROM City ORDER by ID DESC LIMIT 50,5';
if ($result = mysqli_query($link, $query)) {
 /* fetch associative array */
 while ($row = mysqli_fetch_row($result)) {
 printf ('%s (%s)\n', $row[0], $row[1]);
 }
 /* free result set */
 mysqli_free_result($result);
}
/* close connection */
mysqli_close($link);
?>

The above examples will output: 

Pueblo (USA)
Arvada (USA)
Cape Coral (USA)
Green Bay (USA)
Santa Clara (USA)

See Also

mysqli_fetch_array
mysqli_fetch_assoc
mysqli_fetch_object
mysqli_query
mysqli_data_seek
mysqli_result::$field_count, mysqli_num_fields

Description

Object oriented styleint mysqli_result->field_count ;

Procedural styleint mysqli_num_fields(mysqli_result result);

Returns the number of fields from specified result set.

Parameters

result

Procedural style only: A result set identifier returned by mysqli_query, mysqli_store_result or mysqli_use_result.

Return Values

The number of fields from a result set.

Examples

Example 20.194. Object oriented style

<?php
$mysqli = new mysqli('localhost', 'my_user', 'my_password', 'world');
/* check connection */
if (mysqli_connect_errno()) {
 printf('Connect failed: %s\n', mysqli_connect_error());
 exit();
}
if ($result = $mysqli->query('SELECT * FROM City ORDER BY ID LIMIT 1')) {
 /* determine number of fields in result set */
 $field_cnt = $result->field_count;
 printf('Result set has %d fields.\n', $field_cnt);
 /* close result set */
 $result->close();
}
/* close connection */
$mysqli->close();
?>

Example 20.195. Procedural style

<?php
$link = mysqli_connect('localhost', 'my_user', 'my_password', 'world');
/* check connection */
if (mysqli_connect_errno()) {
 printf('Connect failed: %s\n', mysqli_connect_error());
 exit();
}
if ($result = mysqli_query($link, 'SELECT * FROM City ORDER BY ID LIMIT 1')) {
 /* determine number of fields in result set */
 $field_cnt = mysqli_num_fields($result);
 printf('Result set has %d fields.\n', $field_cnt);
 /* close result set */
 mysqli_free_result($result);
}
/* close connection */
mysqli_close($link);
?>

The above examples will output: 

Result set has 5 fields.

See Also

mysqli_fetch_field
mysqli_result::field_seek, mysqli_field_seek

Description

Object oriented stylebool mysqli_result::field_seek(int fieldnr);

Procedural stylebool mysqli_field_seek(mysqli_result result,
int fieldnr);

Sets the field cursor to the given offset. The next call to mysqli_fetch_field will retrieve the field definition of the column associated with that offset.Note

To seek to the beginning of a row, pass an offset value of zero.

Parameters

result

Procedural style only: A result set identifier returned by mysqli_query, mysqli_store_result or mysqli_use_result.

fieldnr

The field number. This value must be in the range from 0 to number of fields - 1.

Return Values

Returns TRUE on success or FALSE on failure.

Examples

Example 20.196. Object oriented style

<?php
$mysqli = new mysqli('localhost', 'my_user', 'my_password', 'world');
/* check connection */
if (mysqli_connect_errno()) {
 printf('Connect failed: %s\n', mysqli_connect_error());
 exit();
}
$query = 'SELECT Name, SurfaceArea from Country ORDER BY Code LIMIT 5';
if ($result = $mysqli->query($query)) {
 /* Get field information for 2nd column */
 $result->field_seek(1);
 $finfo = $result->fetch_field();
 printf('Name: %s\n', $finfo->name);
 printf('Table: %s\n', $finfo->table);
 printf('max. Len: %d\n', $finfo->max_length);
 printf('Flags: %d\n', $finfo->flags);
 printf('Type: %d\n\n', $finfo->type);
 $result->close();
}
/* close connection */
$mysqli->close();
?>

Example 20.197. Procedural style

<?php
$link = mysqli_connect('localhost', 'my_user', 'my_password', 'world');
/* check connection */
if (mysqli_connect_errno()) {
 printf('Connect failed: %s\n', mysqli_connect_error());
 exit();
}
$query = 'SELECT Name, SurfaceArea from Country ORDER BY Code LIMIT 5';
if ($result = mysqli_query($link, $query)) {
 /* Get field information for 2nd column */
 mysqli_field_seek($result, 1);
 $finfo = mysqli_fetch_field($result);
 printf('Name: %s\n', $finfo->name);
 printf('Table: %s\n', $finfo->table);
 printf('max. Len: %d\n', $finfo->max_length);
 printf('Flags: %d\n', $finfo->flags);
 printf('Type: %d\n\n', $finfo->type);
 mysqli_free_result($result);
}
/* close connection */
mysqli_close($link);
?>

The above examples will output: 

Name: SurfaceArea Table: Country max. Len: 10
Flags: 32769
Type: 4

See Also

mysqli_fetch_field
mysqli_result::free, mysqli_free_result

Description

Object oriented stylevoid mysqli_result::free();
void mysqli_result::close();
void mysqli_result::free_result();

Procedural stylevoid mysqli_free_result(mysqli_result result);

Frees the memory associated with the result.Note

You should always free your result with mysqli_free_result, when your result object is not needed anymore.

Parameters

result

Procedural style only: A result set identifier returned by mysqli_query, mysqli_store_result or mysqli_use_result.

Return Values

No value is returned.

See Also

mysqli_query
mysqli_stmt_store_result
mysqli_store_result
mysqli_use_result
mysqli_result::$lengths, mysqli_fetch_lengths

Description

Object oriented stylearray mysqli_result->lengths ;

Procedural stylearray mysqli_fetch_lengths(mysqli_result result);

The mysqli_fetch_lengths function returns an array containing the lengths of every column of the current row within the result set.

Parameters

result

Procedural style only: A result set identifier returned by mysqli_query, mysqli_store_result or mysqli_use_result.

Return Values

An array of integers representing the size of each column (not including any terminating null characters). FALSE if an error occurred.

mysqli_fetch_lengths is valid only for the current row of the result set. It returns FALSE if you call it before calling mysqli_fetch_row/array/object or after retrieving all rows in the result.

Examples

Example 20.198. Object oriented style

<?php
$mysqli = new mysqli('localhost', 'my_user', 'my_password', 'world');
/* check connection */
if (mysqli_connect_errno()) {
 printf('Connect failed: %s\n', mysqli_connect_error());
 exit();
}
$query = 'SELECT * from Country ORDER BY Code LIMIT 1';
if ($result = $mysqli->query($query)) {
 $row = $result->fetch_row();
 /* display column lengths */
 foreach ($result->lengths as $i => $val) {
 printf('Field %2d has Length %2d\n', $i+1, $val);
 }
 $result->close();
}
/* close connection */
$mysqli->close();
?>

Example 20.199. Procedural style

<?php
$link = mysqli_connect('localhost', 'my_user', 'my_password', 'world');
/* check connection */
if (mysqli_connect_errno()) {
 printf('Connect failed: %s\n', mysqli_connect_error());
 exit();
}
$query = 'SELECT * from Country ORDER BY Code LIMIT 1';
if ($result = mysqli_query($link, $query)) {
 $row = mysqli_fetch_row($result);
 /* display column lengths */
 foreach (mysqli_fetch_lengths($result) as $i => $val) {
 printf('Field %2d has Length %2d\n', $i+1, $val);
 }
 mysqli_free_result($result);
}
/* close connection */
mysqli_close($link);
?>

The above examples will output: 

Field 1 has Length 3
Field 2 has Length 5
Field 3 has Length 13
Field 4 has Length 9
Field 5 has Length 6
Field 6 has Length 1
Field 7 has Length 6
Field 8 has Length 4
Field 9 has Length 6
Field 10 has Length 6
Field 11 has Length 5
Field 12 has Length 44
Field 13 has Length 7
Field 14 has Length 3
Field 15 has Length 2
mysqli_result::$num_rows, mysqli_num_rows

Description

Object oriented styleint mysqli_result->num_rows ;

Procedural styleint mysqli_num_rows(mysqli_result result);

Returns the number of rows in the result set.

The behaviour of mysqli_num_rows depends on whether buffered or unbuffered result sets are being used. For unbuffered result sets, mysqli_num_rows will not return the correct number of rows until all the rows in the result have been retrieved.

Parameters

result

Procedural style only: A result set identifier returned by mysqli_query, mysqli_store_result or mysqli_use_result.

Return Values

Returns number of rows in the result set.Note

If the number of rows is greater than MAXINT , the number will be returned as a string.

Examples

Example 20.200. Object oriented style

<?php
$mysqli = new mysqli('localhost', 'my_user', 'my_password', 'world');
/* check connection */
if (mysqli_connect_errno()) {
 printf('Connect failed: %s\n', mysqli_connect_error());
 exit();
}
if ($result = $mysqli->query('SELECT Code, Name FROM Country ORDER BY Name')) {
 /* determine number of rows result set */
 $row_cnt = $result->num_rows;
 printf('Result set has %d rows.\n', $row_cnt);
 /* close result set */
 $result->close();
}
/* close connection */
$mysqli->close();
?>

Example 20.201. Procedural style

<?php
$link = mysqli_connect('localhost', 'my_user', 'my_password', 'world');
/* check connection */
if (mysqli_connect_errno()) {
 printf('Connect failed: %s\n', mysqli_connect_error());
 exit();
}
if ($result = mysqli_query($link, 'SELECT Code, Name FROM Country ORDER BY Name')) {
 /* determine number of rows result set */
 $row_cnt = mysqli_num_rows($result);
 printf('Result set has %d rows.\n', $row_cnt);
 /* close result set */
 mysqli_free_result($result);
}
/* close connection */
mysqli_close($link);
?>

The above examples will output: 

Result set has 239 rows.

See Also

mysqli_affected_rows
mysqli_store_result
mysqli_use_result
mysqli_query

The mysqli_driver class (mysqli_driver)

mysqli_driver::embedded_server_end, mysqli_embedded_server_end
mysqli_driver::embedded_server_start, mysqli_embedded_server_start

MySQLi Driver. 

 mysqli_driver {

 mysqli_driver
 Properties public readonly string client_info ;

 public readonly string client_version ;

 public readonly string driver_version ;

 public readonly string embedded ;

 public bool reconnect ;

 public int report_mode ;

Methods void mysqli_driver::embedded_server_end();

 bool mysqli_driver::embedded_server_start(bool start,

 array arguments,

 array groups);

}
client_info

The Client API header version

client_version

The Client version

driver_version

The MySQLi Driver version

embedded

Whether MySQLi Embedded support is enabled

reconnect

Allow or prevent reconnect (see the mysqli.reconnect INI directive)

report_mode

Set to MYSQLI_REPORT_OFF , MYSQLI_REPORT_ALL or any combination of MYSQLI_REPORT_STRICT (throw Exceptions for errors), MYSQLI_REPORT_ERROR (report errors) and MYSQLI_REPORT_INDEX (errors regarding indexes). See also mysqli_report.

mysqli_driver::embedded_server_end, mysqli_embedded_server_end

Description

Object oriented stylevoid mysqli_driver::embedded_server_end();

Procedural stylevoid mysqli_embedded_server_end(); Warning

This function is currently not documented; only its argument list is available.

mysqli_driver::embedded_server_start, mysqli_embedded_server_start

Description

Object oriented stylebool mysqli_driver::embedded_server_start(bool start,
array arguments,
array groups);

Procedural stylebool mysqli_embedded_server_start(bool start,
array arguments,
array groups); Warning

This function is currently not documented; only its argument list is available.

The mysqli_warning class (mysqli_warning)

mysqli_warning::__construct
mysqli_warning::next

Represents a MariaDB warning. 

 mysqli_warning {

 mysqli_warning
 Properties public message ;

 public sqlstate ;

 public errno ;

Methods public mysqli_warning::__construct();

 public void mysqli_warning::next();

}
message

Message string

sqlstate

SQL state

errno

Error number

mysqli_warning::__construct

Description

public mysqli_warning::__construct(); Warning

This function is currently not documented; only its argument list is available.

Parameters

This function has no parameters.

Return Values

mysqli_warning::next

Description

public void mysqli_warning::next(); Warning

This function is currently not documented; only its argument list is available.

Parameters

This function has no parameters.

Return Values

The mysqli_sql_exception class (mysqli_sql_exception)

The mysqli exception handling class. 

 mysqli_sql_exception {

 mysqli_sql_exception, extends RuntimeException
 Properties protected code ;

 protected sqlstate ;

}
message

The error message.

file

The file with the error.

line

The line with the error.

code

The code causing the error.

sqlstate

The sql state with the error.

Aliases and deprecated Mysqli Functions

mysqli_bind_param
mysqli_bind_result
mysqli_client_encoding
mysqli_connect
mysqli_disable_rpl_parse
mysqli_enable_reads_from_master
mysqli_enable_rpl_parse
mysqli_escape_string
mysqli_execute
mysqli_fetch
mysqli_get_cache_stats
mysqli_get_metadata
mysqli_master_query
mysqli_param_count
mysqli_report
mysqli_rpl_parse_enabled
mysqli_rpl_probe
mysqli_send_long_data
mysqli_set_opt
mysqli_slave_query
mysqli_bind_param

Description

This function is an alias of mysqli_stmt_bind_param.

Notes

Note

mysqli_bind_param is deprecated and will be removed.

See Also

mysqli_stmt_bind_param
mysqli_bind_result

Description

This function is an alias of mysqli_stmt_bind_result.

Notes

Note

mysqli_bind_result is deprecated and will be removed.

See Also

mysqli_stmt_bind_result
mysqli_client_encoding

Description

This function is an alias of mysqli_character_set_name.

See Also

mysqli_real_escape_string
mysqli_connect

Description

This function is an alias of: mysqli::__construct

mysqli_disable_rpl_parse

Description

bool mysqli_disable_rpl_parse(mysqli link); Warning

This function is currently not documented; only its argument list is available.Warning

This function has been DEPRECATED and REMOVED as of PHP 5.3.0.

mysqli_enable_reads_from_master

Description

bool mysqli_enable_reads_from_master(mysqli link); Warning

This function is currently not documented; only its argument list is available.Warning

This function has been DEPRECATED and REMOVED as of PHP 5.3.0.

mysqli_enable_rpl_parse

Description

bool mysqli_enable_rpl_parse(mysqli link); Warning

This function is currently not documented; only its argument list is available.Warning

This function has been DEPRECATED and REMOVED as of PHP 5.3.0.

mysqli_escape_string

Description

This function is an alias of: mysqli_real_escape_string.

mysqli_execute

Description

This function is an alias of mysqli_stmt_execute.

Notes

Note

mysqli_execute is deprecated and will be removed.

See Also

mysqli_stmt_execute
mysqli_fetch

Description

This function is an alias of mysqli_stmt_fetch.

Notes

Note

mysqli_fetch is deprecated and will be removed.

See Also

mysqli_stmt_fetch
mysqli_get_cache_stats

Description

array mysqli_get_cache_stats(); Warning

This function is currently not documented; only its argument list is available.

Returns client Zval cache statistics. Available only with mysqlnd.

Parameters

Return Values

Returns an array with client Zval cache stats if success, FALSE otherwise.

Examples

Example 20.202. A mysqli_get_cache_stats example 

<?php
$link = mysqli_connect();
print_r(mysqli_get_cache_stats());
?>

The above example will output something similar to: 

Array
(
 [bytes_sent] => 43
 [bytes_received] => 80
 [packets_sent] => 1
 [packets_received] => 2
 [protocol_overhead_in] => 8
 [protocol_overhead_out] => 4
 [bytes_received_ok_packet] => 11
 [bytes_received_eof_packet] => 0
 [bytes_received_rset_header_packet] => 0
 [bytes_received_rset_field_meta_packet] => 0
 [bytes_received_rset_row_packet] => 0
 [bytes_received_prepare_response_packet] => 0
 [bytes_received_change_user_packet] => 0
 [packets_sent_command] => 0
 [packets_received_ok] => 1
 [packets_received_eof] => 0
 [packets_received_rset_header] => 0
 [packets_received_rset_field_meta] => 0
 [packets_received_rset_row] => 0
 [packets_received_prepare_response] => 0
 [packets_received_change_user] => 0
 [result_set_queries] => 0
 [non_result_set_queries] => 0
 [no_index_used] => 0
 [bad_index_used] => 0
 [slow_queries] => 0
 [buffered_sets] => 0
 [unbuffered_sets] => 0
 [ps_buffered_sets] => 0
 [ps_unbuffered_sets] => 0
 [flushed_normal_sets] => 0
 [flushed_ps_sets] => 0
 [ps_prepared_never_executed] => 0
 [ps_prepared_once_executed] => 0
 [rows_fetched_from_server_normal] => 0
 [rows_fetched_from_server_ps] => 0
 [rows_buffered_from_client_normal] => 0
 [rows_buffered_from_client_ps] => 0
 [rows_fetched_from_client_normal_buffered] => 0
 [rows_fetched_from_client_normal_unbuffered] => 0
 [rows_fetched_from_client_ps_buffered] => 0
 [rows_fetched_from_client_ps_unbuffered] => 0
 [rows_fetched_from_client_ps_cursor] => 0
 [rows_skipped_normal] => 0
 [rows_skipped_ps] => 0
 [copy_on_write_saved] => 0
 [copy_on_write_performed] => 0
 [command_buffer_too_small] => 0
 [connect_success] => 1
 [connect_failure] => 0
 [connection_reused] => 0
 [reconnect] => 0
 [pconnect_success] => 0
 [active_connections] => 1
 [active_persistent_connections] => 0
 [explicit_close] => 0
 [implicit_close] => 0
 [disconnect_close] => 0
 [in_middle_of_command_close] => 0
 [explicit_free_result] => 0
 [implicit_free_result] => 0
 [explicit_stmt_close] => 0
 [implicit_stmt_close] => 0
 [mem_emalloc_count] => 0
 [mem_emalloc_ammount] => 0
 [mem_ecalloc_count] => 0
 [mem_ecalloc_ammount] => 0
 [mem_erealloc_count] => 0
 [mem_erealloc_ammount] => 0
 [mem_efree_count] => 0
 [mem_malloc_count] => 0
 [mem_malloc_ammount] => 0
 [mem_calloc_count] => 0
 [mem_calloc_ammount] => 0
 [mem_realloc_count] => 0
 [mem_realloc_ammount] => 0
 [mem_free_count] => 0
 [proto_text_fetched_null] => 0
 [proto_text_fetched_bit] => 0
 [proto_text_fetched_tinyint] => 0
 [proto_text_fetched_short] => 0
 [proto_text_fetched_int24] => 0
 [proto_text_fetched_int] => 0
 [proto_text_fetched_bigint] => 0
 [proto_text_fetched_decimal] => 0
 [proto_text_fetched_float] => 0
 [proto_text_fetched_double] => 0
 [proto_text_fetched_date] => 0
 [proto_text_fetched_year] => 0
 [proto_text_fetched_time] => 0
 [proto_text_fetched_datetime] => 0
 [proto_text_fetched_timestamp] => 0
 [proto_text_fetched_string] => 0
 [proto_text_fetched_blob] => 0
 [proto_text_fetched_enum] => 0
 [proto_text_fetched_set] => 0
 [proto_text_fetched_geometry] => 0
 [proto_text_fetched_other] => 0
 [proto_binary_fetched_null] => 0
 [proto_binary_fetched_bit] => 0
 [proto_binary_fetched_tinyint] => 0
 [proto_binary_fetched_short] => 0
 [proto_binary_fetched_int24] => 0
 [proto_binary_fetched_int] => 0
 [proto_binary_fetched_bigint] => 0
 [proto_binary_fetched_decimal] => 0
 [proto_binary_fetched_float] => 0
 [proto_binary_fetched_double] => 0
 [proto_binary_fetched_date] => 0
 [proto_binary_fetched_year] => 0
 [proto_binary_fetched_time] => 0
 [proto_binary_fetched_datetime] => 0
 [proto_binary_fetched_timestamp] => 0
 [proto_binary_fetched_string] => 0
 [proto_binary_fetched_blob] => 0
 [proto_binary_fetched_enum] => 0
 [proto_binary_fetched_set] => 0
 [proto_binary_fetched_geometry] => 0
 [proto_binary_fetched_other] => 0
)

See Also

Stats description
mysqli_get_metadata

Description

This function is an alias of mysqli_stmt_result_metadata.

Notes

Note

mysqli_get_metadata is deprecated and will be removed.

See Also

mysqli_stmt_result_metadata
mysqli_master_query

Description

bool mysqli_master_query(mysqli link,
string query); Warning

This function is currently not documented; only its argument list is available.Warning

This function has been DEPRECATED and REMOVED as of PHP 5.3.0.

mysqli_param_count

Description

This function is an alias of mysqli_stmt_param_count.

Notes

Note

mysqli_param_count is deprecated and will be removed.

See Also

mysqli_stmt_param_count
mysqli_report

Description

bool mysqli_report(int flags);

mysqli_report is a powerful function to improve your queries and code during development and testing phase. Depending on the flags it reports errors from mysqli function calls or queries which don't use an index (or use a bad index).

Parameters

flags

Table 20.24. Supported flags

Name Description
MYSQLI_REPORT_OFF Turns reporting off
MYSQLI_REPORT_ERROR Report errors from mysqli function calls
MYSQLI_REPORT_STRICT Throw mysqli_sql_exception for errors instead of warnings
MYSQLI_REPORT_INDEX Report if no index or bad index was used in a query
MYSQLI_REPORT_ALL Set all options (report all)

Return Values

Returns TRUE on success or FALSE on failure.

Changelog

Version Description
& 5.3.4 Changing the reporting mode is now be per-request, rather than per-process.

Examples

Example 20.203. Object oriented style

<?php
/* activate reporting */
mysqli_report(MYSQLI_REPORT_ALL);
$mysqli = new mysqli('localhost', 'my_user', 'my_password', 'world');
/* check connection */
if (mysqli_connect_errno()) {
 printf('Connect failed: %s\n', mysqli_connect_error());
 exit();
}
/* this query should report an error */
$result = $mysqli->query('SELECT Name FROM Nonexistingtable WHERE population > 50000');
/* this query should report a bad index */
$result = $mysqli->query('SELECT Name FROM City WHERE population > 50000');
$result->close();
$mysqli->close();
?>

See Also

mysqli_driver::$report_mode
mysqli_debug
mysqli_dump_debug_info
mysqli_rpl_parse_enabled

Description

int mysqli_rpl_parse_enabled(mysqli link); Warning

This function is currently not documented; only its argument list is available.Warning

This function has been DEPRECATED and REMOVED as of PHP 5.3.0.

mysqli_rpl_probe

Description

bool mysqli_rpl_probe(mysqli link); Warning

This function is currently not documented; only its argument list is available.Warning

This function has been DEPRECATED and REMOVED as of PHP 5.3.0.

mysqli_send_long_data

Description

This function is an alias of mysqli_stmt_send_long_data.

Notes

Note

mysqli_send_long_data is deprecated and will be removed.

See Also

mysqli_stmt_send_long_data
mysqli_set_opt

Description

This function is an alias of mysqli_options.

mysqli_slave_query

Description

bool mysqli_slave_query(mysqli link,
string query); Warning

This function is currently not documented; only its argument list is available.Warning

This function has been DEPRECATED and REMOVED as of PHP 5.3.0.

MySQL Native Driver (Mysqlnd)

Overview
Installation
Runtime Configuration
Persistent Connections
Statistics
Notes
MySQL Native Driver Plugin API

MySQL Native Driver is a replacement for the MariaDB Client Library (libmysql). MariaDB Native Driver is part of the official PHP sources as of PHP 5.3.0.

The MariaDB database extensions MariaDB extension, mysqli and PDO MYSQL all communicate with the MariaDB server. In the past, this was done by the extension using the services provided by the MariaDB Client Library. The extensions were compiled against the MariaDB Client Library in order to use its client-server protocol.

With MariaDB Native Driver there is now an alternative, as the MariaDB database extensions can be compiled to use MariaDB Native Driver instead of the MariaDB Client Library.

MySQL Native Driver is written in C as a PHP extension.

Overview

What it is not

Although MariaDB Native Driver is written as a PHP extension, it is important to note that it does not provide a new API to the PHP programmer. The programmer APIs for MariaDB database connectivity are provided by the MariaDB extension, mysqli and PDO MYSQL. These extensions can now use the services of MariaDB Native Driver to communicate with the MariaDB Server. Therefore, you should not think of MariaDB Native Driver as an API.

Why use it?

Using the MariaDB Native Driver offers a number of advantages over using the MariaDB Client Library.

The older MariaDB Client Library was written by MariaDB Foundation (now Oracle Corporation) and so was released under the MariaDB license. This ultimately led to MariaDB support being disabled by default in PHP. However, the MariaDB Native Driver has been developed as part of the PHP project, and is therefore released under the PHP license. This removes licensing issues that have been problematic in the past.

Also, in the past, you needed to build the MariaDB database extensions against a copy of the MariaDB Client Library. This typically meant you needed to have MariaDB installed on a machine where you were building the PHP source code. Also, when your PHP application was running, the MariaDB database extensions would call down to the MariaDB Client library file at run time, so the file needed to be installed on your system. With MariaDB Native Driver that is no longer the case as it is included as part of the standard distribution. So you do not need MariaDB installed in order to build PHP or run PHP database applications.

Because MariaDB Native Driver is written as a PHP extension, it is tightly coupled to the workings of PHP. This leads to gains in efficiency, especially when it comes to memory usage, as the driver uses the PHP memory management system. It also supports the PHP memory limit. Using MariaDB Native Driver leads to comparable or better performance than using MariaDB Client Library, it always ensures the most efficient use of memory. One example of the memory efficiency is the fact that when using the MariaDB Client Library, each row is stored in memory twice, whereas with the MariaDB Native Driver each row is only stored once in memory.

Special features

MySQL Native Driver also provides some special features not available when the MariaDB database extensions use MariaDB Client Library. These special features are listed below:

The performance statistics facility can prove to be very useful in identifying performance bottlenecks.

MySQL Native Driver also allows for persistent connections when used with the mysqli extension.

SSL Support

MySQL Native Driver has supported SSL since PHP version 5.3.3

Compressed Protocol Support

As of PHP 5.3.2 MariaDB Native Driver supports the compressed client server protocol. MariaDB Native Driver did not support this in 5.3.0 and 5.3.1. Extensions such as ext/mysql, ext/mysqli, that are configured to use MariaDB Native Driver, can also take advantage of this feature. Note that PDO_MYSQL does NOT support compression when used together with mysqlnd.

Named Pipes Support

Named pipes support for Windows was added in PHP version 5.4.0.

Installation

Changelog

Table 20.25. Changelog

Version Description
5.3.0 The MariaDB Native Driver was added, with support for all MariaDB extensions (i.e., mysql, mysqli and PDO_MYSQL). Passing in mysqlnd to the appropriate configure switch enables this support.
5.4.0 The MariaDB Native Driver is now the default for all MariaDB extensions (i.e., mysql, mysqli and PDO_MYSQL). Passing in mysqlnd to configure is now optional.

Installation on Unix

The MariaDB database extensions must be configured to use the MariaDB Client Library. In order to use the MariaDB Native Driver, PHP needs to be built specifying that the MariaDB database extensions are compiled with MariaDB Native Driver support. This is done through configuration options prior to building the PHP source code.

For example, to build the MariaDB extension, mysqli and PDO MYSQL using the MariaDB Native Driver, the following command would be given: 

 ./configure --with-mysql=mysqlnd \
--with-mysqli=mysqlnd \
--with-pdo-mysql=mysqlnd \
[other options]

Installation on Windows

In the official PHP Windows distributions from 5.3 onwards, MariaDB Native Driver is enabled by default, so no additional configuration is required to use it. All MariaDB database extensions will use MariaDB Native Driver in this case.

Runtime Configuration

The behaviour of these functions is affected by settings in php.ini.

Table 20.26. MariaDB Native Driver Configuration Options

Name Default Changeable Changelog
mysqlnd.collect_statistics '1' PHP_INI_SYSTEM Available since PHP 5.3.0.
mysqlnd.collect_memory_statistics '0' PHP_INI_SYSTEM Available since PHP 5.3.0.
mysqlnd.debug '0' PHP_INI_SYSTEM Available since PHP 5.3.0.
mysqlnd.log_mask 0 PHP_INI_ALL Available since PHP 5.3.0
mysqlnd.mempool_default_size 16000 PHP_INI_ALL Available since PHP 5.3.3
mysqlnd.net_read_timeout '31536000' PHP_INI_SYSTEM Available since PHP 5.3.0.
mysqlnd.net_cmd_buffer_size - '2048', 5.3.1 - '4096' PHP_INI_SYSTEM Available since PHP 5.3.0.
mysqlnd.net_read_buffer_size '32768' PHP_INI_SYSTEM Available since PHP 5.3.0.

For further details and definitions of the PHP_INI_* modes, see the http://www.php.net/manual/en/configuration.changes.modes.

Here's a short explanation of the configuration directives.

mysqlnd.collect_statistics boolean

Enables the collection of various client statistics which can be accessed through mysqli_get_client_stats, mysqli_get_connection_stats, mysqli_get_cache_stats and are shown in mysqlnd section of the output of the phpinfo function as well.

This configuration setting enables all MySQL Native Driver statistics except those relating to memory management.

mysqlnd.collect_memory_statistics boolean

Enable the collection of various memory statistics which can be accessed through mysqli_get_client_stats, mysqli_get_connection_stats, mysqli_get_cache_stats and are shown in mysqlnd section of the output of the phpinfo function as well.

This configuration setting enables the memory management statistics within the overall set of MySQL Native Driver statistics.

mysqlnd.debug string

Records communication from all extensions using mysqlnd to the specified log file.

The format of the directive is mysqlnd.debug = 'option1[,parameter_option1][:option2[,parameter_option2]]'.

The options for the format string are as follows:

  • A[,file] - Appends trace output to specified file. Also ensures that data is written after each write. This is done by closing and reopening the trace file (this is slow). It helps ensure a complete log file should the application crash.
  • a[,file] - Appends trace output to the specified file.
  • d - Enables output from DBUG_<N> macros for the current state. May be followed by a list of keywords which selects output only for the DBUG macros with that keyword. An empty list of keywords implies output for all macros.
  • f[,functions] - Limits debugger actions to the specified list of functions. An empty list of functions implies that all functions are selected.
  • F - Marks each debugger output line with the name of the source file containing the macro causing the output.
  • i - Marks each debugger output line with the PID of the current process.
  • L - Marks each debugger output line with the name of the source file line number of the macro causing the output.
  • n - Marks each debugger output line with the current function nesting depth
  • o[,file] - Similar to a[,file] but overwrites old file, and does not append.
  • O[,file] - Similar to A[,file] but overwrites old file, and does not append.
  • t[,N] - Enables function control flow tracing. The maximum nesting depth is specified by N, and defaults to 200.
  • x - This option activates profiling.

Example: 

d:t:x:O,/tmp/mysqlnd.trace
Note

This feature is only available with a debug build of PHP. Works on Microsoft Windows if using a debug build of PHP and PHP was built using Microsoft Visual C version 9 and above.

mysqlnd.log_mask integer

Defines which queries will be logged. The default 0, which disables logging. Define using an integer, and not with PHP constants. For example, a value of 48 (16 + 32) will log slow queries which either use 'no good index' (SERVER_QUERY_NO_GOOD_INDEX_USED = 16) or no index at all (SERVER_QUERY_NO_INDEX_USED = 32). A value of 2043 (1 + 2 + 8 + ... + 1024) will log all slow query types.

The types are as follows: SERVER_STATUS_IN_TRANS=1, SERVER_STATUS_AUTOCOMMIT=2, SERVER_MORE_RESULTS_EXISTS=8, SERVER_QUERY_NO_GOOD_INDEX_USED=16, SERVER_QUERY_NO_INDEX_USED=32, SERVER_STATUS_CURSOR_EXISTS=64, SERVER_STATUS_LAST_ROW_SENT=128, SERVER_STATUS_DB_DROPPED=256, SERVER_STATUS_NO_BACKSLASH_ESCAPES=512, and SERVER_QUERY_WAS_SLOW=1024.

mysqlnd.mempool_default_size integer

Default size of the mysqlnd memory pool, which is used by result sets.

mysqlnd.net_read_timeout integer

mysqlnd and the MariaDB Client Library, libmysql use different networking APIs. mysqlnd uses PHP streams, whereas libmysql uses its own wrapper around the operating level network calls. PHP, by default, sets a read timeout of 60s for streams. This is set via php.ini, default_socket_timeout. This default applies to all streams that set no other timeout value. mysqlnd does not set any other value and therefore connections of long running queries can be disconnected after default_socket_timeout seconds resulting in an error message "- MariaDB Server has gone away". The MariaDB Client Library sets a default timeout of 365 * 24 * 3600 seconds (1 year) and waits for other timeouts to occur, such as TCP/IP timeouts. mysqlnd now uses the same very long timeout. The value is configurable through a new php.ini setting: mysqlnd.net_read_timeout. mysqlnd.net_read_timeout gets used by any extension (ext/mysql, ext/mysqli, PDO_MySQL) that uses mysqlnd. mysqlnd tells PHP Streams to use mysqlnd.net_read_timeout. Please note that there may be subtle differences between MYSQL_OPT_READ_TIMEOUT from the MariaDB Client Library and PHP Streams, for example MYSQL_OPT_READ_TIMEOUT is documented to work only for TCP/IP connections and, prior to MariaDB 5.1.2, only for Windows. PHP streams may not have this limitation. Please check the streams documentation, if in doubt.

mysqlnd.net_cmd_buffer_size long

mysqlnd allocates an internal command/network buffer of mysqlnd.net_cmd_buffer_size (in php.ini) bytes for every connection. If a MariaDB Client Server protocol command, for example, COM_QUERY ("normal" query), does not fit into the buffer, mysqlnd will grow the buffer to the size required for sending the command. Whenever the buffer gets extended for one connection, command_buffer_too_small will be incremented by one.

If mysqlnd has to grow the buffer beyond its initial size of mysqlnd.net_cmd_buffer_size bytes for almost every connection, you should consider increasing the default size to avoid re-allocations.

The default buffer size is 2048 bytes in PHP 5.3.0. In later versions the default is 4096 bytes. The default can changed either through the php.ini setting mysqlnd.net_cmd_buffer_size or using mysqli_options(MYSQLI_OPT_NET_CMD_BUFFER_SIZE, int size).

It is recommended that the buffer size be set to no less than 4096 bytes because mysqlnd also uses it when reading certain communication packet from MySQL. In PHP 5.3.0, mysqlnd will not grow the buffer if MariaDB sends a packet that is larger than the current size of the buffer. As a consequence, mysqlnd is unable to decode the packet and the client application will get an error. There are only two situations when the packet can be larger than the 2048 bytes default of mysqlnd.net_cmd_buffer_size in PHP 5.3.0: the packet transports a very long error message, or the packet holds column meta data from COM_LIST_FIELD (mysql_list_fields() and the meta data come from a string column with a very long default value (>1900 bytes).

As of PHP 5.3.2 mysqlnd does not allow setting buffers smaller than 4096 bytes.

The value can also be set using mysqli_options(link, MYSQLI_OPT_NET_CMD_BUFFER_SIZE, size).

mysqlnd.net_read_buffer_size long

Maximum read chunk size in bytes when reading the body of a MariaDB command packet. The MariaDB client server protocol encapsulates all its commands in packets. The packets consist of a small header and a body with the actual payload. The size of the body is encoded in the header. mysqlnd reads the body in chunks of MIN(header.size, mysqlnd.net_read_buffer_size) bytes. If a packet body is larger than mysqlnd.net_read_buffer_size bytes, mysqlnd has to call read() multiple times.

The value can also be set using mysqli_options(link, MYSQLI_OPT_NET_READ_BUFFER_SIZE, size).

Persistent Connections

Using Persistent Connections

If mysqli is used with mysqlnd, when a persistent connection is created it generates a COM_CHANGE_USER (mysql_change_user()) call on the server. This ensures that re-authentication of the connection takes place.

As there is some overhead associated with the COM_CHANGE_USER call, it is possible to switch this off at compile time. Reusing a persistent connection will then generate a COM_PING (mysql_ping) call to simply test the connection is reusable.

Generation of COM_CHANGE_USER can be switched off with the compile flag MYSQLI_NO_CHANGE_USER_ON_PCONNECT. For example: 

shell# CFLAGS="-DMYSQLI_NO_CHANGE_USER_ON_PCONNECT" ./configure --with-mysql=/usr/local/mysql/ --with-mysqli=/usr/local/mysql/bin/mysql_config --with-pdo-mysql=/usr/local/mysql/bin/mysql_config --enable-debug && make clean && make -j6

Or alternatively: 

shell# export CFLAGS="-DMYSQLI_NO_CHANGE_USER_ON_PCONNECT"
shell# configure --whatever-option shell# make clean shell# make

Note that only mysqli on mysqlnd uses COM_CHANGE_USER. Other extension-driver combinations use COM_PING on initial use of a persistent connection.

Statistics

Using Statistical Data

MySQL Native Driver contains support for gathering statistics on the communication between the client and the server. The statistics gathered are of three main types:

If you are using the mysqli extension, these statistics can be obtained through three API calls:

Note

Statistics are aggregated among all extensions that use MariaDB Native Driver. For example, when compiling both ext/mysql and ext/mysqli against MariaDB Native Driver, both function calls of ext/mysql and ext/mysqli will change the statistics. There is no way to find out how much a certain API call of any extension that has been compiled against MariaDB Native Driver has impacted a certain statistic. You can configure the PDO MariaDB Driver, ext/mysql and ext/mysqli to optionally use the MariaDB Native Driver. When doing so, all three extensions will change the statistics.

Accessing Client Statistics

To access client statistics, you need to call mysqli_get_client_stats. The function call does not require any parameters.

The function returns an associative array that contains the name of the statistic as the key and the statistical data as the value.

Client statistics can also be accessed by calling the phpinfo function.

Accessing Connection Statistics

To access connection statistics call mysqli_get_connection_stats. This takes the database connection handle as the parameter.

The function returns an associative array that contains the name of the statistic as the key and the statistical data as the value.

Accessing Zval Cache Statistics

The MariaDB Native Driver also collects statistics from its internal Zval cache. These statistics can be accessed by calling mysqli_get_cache_stats.

The Zval cache statistics obtained may lead to a tweaking of php.ini settings related to the Zval cache, resulting in better performance.

Buffered and Unbuffered Result Sets

Result sets can be buffered or unbuffered. Using default settings, ext/mysql and ext/mysqli work with buffered result sets for normal (non prepared statement) queries. Buffered result sets are cached on the client. After the query execution all results are fetched from the MariaDB Server and stored in a cache on the client. The big advantage of buffered result sets is that they allow the server to free all resources allocated to a result set, once the results have been fetched by the client.

Unbuffered result sets on the other hand are kept much longer on the server. If you want to reduce memory consumption on the client, but increase load on the server, use unbuffered results. If you experience a high server load and the figures for unbuffered result sets are high, you should consider moving the load to the clients. Clients typically scale better than servers. "Load" does not only refer to memory buffers - the server also needs to keep other resources open, for example file handles and threads, before a result set can be freed.

Prepared Statements use unbuffered result sets by default. However, you can use mysqli_stmt_store_result to enable buffered result sets.

Statistics returned by MariaDB Native Driver

The following tables show a list of statistics returned by the mysqli_get_client_stats, mysqli_get_connection_stats and mysqli_get_cache_stats functions.

Network

Statistic Scope Description Notes
bytes_sent Connection Number of bytes sent from PHP to the MariaDB server Can be used to check the efficiency of the compression protocol
bytes_received Connection Number of bytes received from MariaDB server Can be used to check the efficiency of the compression protocol
packets_sent Connection Number of MariaDB Client Server protocol packets sent Used for debugging Client Server protocol implementation
packets_received Connection Number of MariaDB Client Server protocol packets received Used for debugging Client Server protocol implementation
protocol_overhead_in Connection MySQL Client Server protocol overhead in bytes for incoming traffic. Currently only the Packet Header (4 bytes) is considered as overhead. protocol_overhead_in = packets_received * 4 Used for debugging Client Server protocol implementation
protocol_overhead_out Connection MySQL Client Server protocol overhead in bytes for outgoing traffic. Currently only the Packet Header (4 bytes) is considered as overhead. protocol_overhead_out = packets_sent * 4 Used for debugging Client Server protocol implementation
bytes_received_ok_packet Connection Total size of bytes of MariaDB Client Server protocol OK packets received. OK packets can contain a status message. The length of the status message can vary and thus the size of an OK packet is not fixed. Used for debugging CS protocol implementation. Note that the total size in bytes includes the size of the header packet (4 bytes, see protocol overhead).
packets_received_ok Connection Number of MariaDB Client Server protocol OK packets received. Used for debugging CS protocol implementation. Note that the total size in bytes includes the size of the header packet (4 bytes, see protocol overhead).
bytes_received_eof_packet Connection Total size in bytes of MariaDB Client Server protocol EOF packets received. EOF can vary in size depending on the server version. Also, EOF can transport an error message. Used for debugging CS protocol implementation. Note that the total size in bytes includes the size of the header packet (4 bytes, see protocol overhead).
packets_received_eof Connection Number of MariaDB Client Server protocol EOF packets. Like with other packet statistics the number of packets will be increased even if PHP does not receive the expected packet but, for example, an error message. Used for debugging CS protocol implementation. Note that the total size in bytes includes the size of the header packet (4 bytes, see protocol overhead).
bytes_received_rset_header_packet Connection Total size in bytes of MariaDB Client Server protocol result set header packets. The size of the packets varies depending on the payload (LOAD LOCAL INFILE, INSERT, UPDATE, SELECT, error message). Used for debugging CS protocol implementation. Note that the total size in bytes includes the size of the header packet (4 bytes, see protocol overhead).
packets_received_rset_header Connection Number of MariaDB Client Server protocol result set header packets. Used for debugging CS protocol implementation. Note that the total size in bytes includes the size of the header packet (4 bytes, see protocol overhead).
bytes_received_rset_field_meta_packet Connection Total size in bytes of MariaDB Client Server protocol result set meta data (field information) packets. Of course the size varies with the fields in the result set. The packet may also transport an error or an EOF packet in case of COM_LIST_FIELDS. Only useful for debugging CS protocol implementation. Note that the total size in bytes includes the size of the header packet (4 bytes, see protocol overhead).
packets_received_rset_field_meta Connection Number of MariaDB Client Server protocol result set meta data (field information) packets. Only useful for debugging CS protocol implementation. Note that the total size in bytes includes the size of the header packet (4 bytes, see protocol overhead).
bytes_received_rset_row_packet Connection Total size in bytes of MariaDB Client Server protocol result set row data packets. The packet may also transport an error or an EOF packet. You can reverse engineer the number of error and EOF packets by substracting rows_fetched_from_server_normal and rows_fetched_from_server_ps from bytes_received_rset_row_packet. Only useful for debugging CS protocol implementation. Note that the total size in bytes includes the size of the header packet (4 bytes, see protocol overhead).
packets_received_rset_row Connection Number of MariaDB Client Server protocol result set row data packets and their total size in bytes. Only useful for debugging CS protocol implementation. Note that the total size in bytes includes the size of the header packet (4 bytes, see protocol overhead).
bytes_received_prepare_response_packet Connection Total size in bytes of MariaDB Client Server protocol OK for Prepared Statement Initialization packets (prepared statement init packets). The packet may also transport an error. The packet size depends on the MariaDB version: 9 bytes with MariaDB and 12 bytes from MariaDB 5.0 on. There is no safe way to know how many errors happened. You may be able to guess that an error has occurred if, for example, you always connect to MariaDB 5.0 or newer and, bytes_received_prepare_response_packet != packets_received_prepare_response * 12. See also ps_prepared_never_executed, ps_prepared_once_executed. Only useful for debugging CS protocol implementation. Note that the total size in bytes includes the size of the header packet (4 bytes, see protocol overhead).
packets_received_prepare_response Connection Number of MariaDB Client Server protocol OK for Prepared Statement Initialization packets (prepared statement init packets). Only useful for debugging CS protocol implementation. Note that the total size in bytes includes the size of the header packet (4 bytes, see protocol overhead).
bytes_received_change_user_packet Connection Total size in bytes of MariaDB Client Server protocol COM_CHANGE_USER packets. The packet may also transport an error or EOF. Only useful for debugging CS protocol implementation. Note that the total size in bytes includes the size of the header packet (4 bytes, see protocol overhead).
packets_received_change_user Connection Number of MariaDB Client Server protocol COM_CHANGE_USER packets Only useful for debugging CS protocol implementation. Note that the total size in bytes includes the size of the header packet (4 bytes, see protocol overhead).
packets_sent_command Connection Number of MariaDB Client Server protocol commands sent from PHP to MariaDB. There is no way to know which specific commands and how many of them have been sent. At its best you can use it to check if PHP has sent any commands to MariaDB to know if you can consider to disable MariaDB support in your PHP binary. There is also no way to reverse engineer the number of errors that may have occurred while sending data to MariaDB. The only error recoded is command_buffer_too_small (see below). Only useful for debugging CS protocol implementation.
bytes_received_real_data_normal Connection Number of bytes of payload fetched by the PHP client from mysqlnd using the text protocol. This is the size of the actual data contained in result sets that do not originate from prepared statements and which have been fetched by the PHP client. Note that although a full result set may have been pulled from MariaDB by mysqlnd, this statistic only counts actual data pulled from mysqlnd by the PHP client. An example of a code sequence that will increase the value is as follows: 
$mysqli = new mysqli();
$res = $mysqli->query('SELECT 'abc'');
$res->fetch_assoc();
$res->close();

Every fetch operation will increase the value.

The statistic will not be increased if the result set is only buffered on the client, but not fetched, such as in the following example: 

$mysqli = new mysqli();
$res = $mysqli->query('SELECT 'abc'');
$res->close();

This statistic is available as of PHP version 5.3.4.

bytes_received_real_data_ps Connection Number of bytes of the payload fetched by the PHP client from mysqlnd using the prepared statement protocol. This is the size of the actual data contained in result sets that originate from prepared statements and which has been fetched by the PHP client. The value will not be increased if the result set is not subsequently read by the PHP client. Note that although a full result set may have been pulled from MariaDB by mysqlnd, this statistic only counts actual data pulled from mysqlnd by the PHP client. See also bytes_received_real_data_normal. This statistic is available as of PHP version 5.3.4.

Result Set

Statistic Scope Description Notes
result_set_queries Connection Number of queries that have generated a result set. Examples of queries that generate a result set: SELECT, SHOW. The statistic will not be incremented if there is an error reading the result set header packet from the line. You may use it as an indirect measure for the number of queries PHP has sent to MySQL, for example, to identify a client that causes a high database load.
non_result_set_queries Connection Number of queries that did not generate a result set. Examples of queries that do not generate a result set: INSERT, UPDATE, LOAD DATA, SHOW. The statistic will not be incremented if there is an error reading the result set header packet from the line. You may use it as an indirect measure for the number of queries PHP has sent to MySQL, for example, to identify a client that causes a high database load.
no_index_used Connection Number of queries that have generated a result set but did not use an index (see also mysqld start option -log-queries-not-using-indexes). If you want these queries to be reported you can use mysqli_report(MYSQLI_REPORT_INDEX) to make ext/mysqli throw an exception. If you prefer a warning instead of an exception use mysqli_report(MYSQLI_REPORT_INDEX ^ MYSQLI_REPORT_STRICT).
bad_index_used Connection Number of queries that have generated a result set and did not use a good index (see also mysqld start option -log-slow-queries). If you want these queries to be reported you can use mysqli_report(MYSQLI_REPORT_INDEX) to make ext/mysqli throw an exception. If you prefer a warning instead of an exception use mysqli_report(MYSQLI_REPORT_INDEX ^ MYSQLI_REPORT_STRICT)
slow_queries Connection SQL statements that took more than long_query_time seconds to execute and required at least min_examined_row_limit rows to be examined. Not reported through mysqli_report
buffered_sets Connection Number of buffered result sets returned by "normal" queries. "Normal" means "not prepared statement" in the following notes. Examples of API calls that will buffer result sets on the client: mysql_query, mysqli_query, mysqli_store_result, mysqli_stmt_get_result. Buffering result sets on the client ensures that server resources are freed as soon as possible and it makes result set scrolling easier. The downside is the additional memory consumption on the client for buffering data. Note that mysqlnd (unlike the MariaDB Client Library) respects the PHP memory limit because it uses PHP internal memory management functions to allocate memory. This is also the reason why memory_get_usage reports a higer memory consumption when using mysqlnd instead of the MariaDB Client Library. memory_get_usage does not measure the memory consumption of the MariaDB Client Library at all because the MariaDB Client Library does not use PHP internal memory management functions monitored by the function!
unbuffered_sets Connection Number of unbuffered result sets returned by normal (non prepared statement) queries. Examples of API calls that will not buffer result sets on the client: mysqli_use_result
ps_buffered_sets Connection Number of buffered result sets returned by prepared statements. By default prepared statements are unbuffered. Examples of API calls that will not buffer result sets on the client: mysqli_stmt_store_result
ps_unbuffered_sets Connection Number of unbuffered result sets returned by prepared statements. By default prepared statements are unbuffered.
flushed_normal_sets Connection Number of result sets from normal (non prepared statement) queries with unread data which have been flushed silently for you. Flushing happens only with unbuffered result sets. Unbuffered result sets must be fetched completely before a new query can be run on the connection otherwise MariaDB will throw an error. If the application does not fetch all rows from an unbuffered result set, mysqlnd does implicitly fetch the result set to clear the line. See also rows_skipped_normal, rows_skipped_ps. Some possible causes for an implicit flush:
  • Faulty client application
  • Client stopped reading after it found what it was looking for but has made MariaDB calculate more records than needed
  • Client application has stopped unexpectedly
flushed_ps_sets Connection Number of result sets from prepared statements with unread data which have been flushed silently for you. Flushing happens only with unbuffered result sets. Unbuffered result sets must be fetched completely before a new query can be run on the connection otherwise MariaDB will throw an error. If the application does not fetch all rows from an unbuffered result set, mysqlnd does implicitly fetch the result set to clear the line. See also rows_skipped_normal, rows_skipped_ps. Some possible causes for an implicit flush:
  • Faulty client application
  • Client stopped reading after it found what it was looking for but has made MariaDB calculate more records than needed
  • Client application has stopped unexpectedly
ps_prepared_never_executed Connection Number of statements prepared but never executed. Prepared statements occupy server resources. You should not prepare a statement if you do not plan to execute it.
ps_prepared_once_executed Connection Number of prepared statements executed only one. One of the ideas behind prepared statements is that the same query gets executed over and over again (with different parameters) and some parsing and other preparation work can be saved, if statement execution is split up in separate prepare and execute stages. The idea is to prepare once and "cache" results, for example, the parse tree to be reused during multiple statement executions. If you execute a prepared statement only once the two stage processing can be inefficient compared to "normal" queries because all the caching means extra work and it takes (limited) server resources to hold the cached information. Consequently, prepared statements that are executed only once may cause performance hurts.
rows_fetched_from_server_normal, rows_fetched_from_server_ps Connection Total number of result set rows successfully fetched from MariaDB regardless if the client application has consumed them or not. Some of the rows may not have been fetched by the client application but have been flushed implicitly. See also packets_received_rset_row
rows_buffered_from_client_normal, rows_buffered_from_client_ps Connection Total number of succesfully buffered rows originating from a 'normal' query or a prepared statement. This is the number of rows that have been fetched from MariaDB and buffered on client. Note that there are two distinct statistics on rows that have been buffered (MySQL to mysqlnd internal buffer) and buffered rows that have been fetched by the client application (mysqlnd internal buffer to client application). If the number of buffered rows is higher than the number of fetched buffered rows it can mean that the client application runs queries that cause larger result sets than needed resulting in rows not read by the client. Examples of queries that will buffer results: mysqli_query, mysqli_store_result
rows_fetched_from_client_normal_buffered, rows_fetched_from_client_ps_buffered Connection Total number of rows fetched by the client from a buffered result set created by a normal query or a prepared statement.
rows_fetched_from_client_normal_unbuffered, rows_fetched_from_client_ps_unbuffered Connection Total number of rows fetched by the client from a unbuffered result set created by a 'normal' query or a prepared statement.
rows_fetched_from_client_ps_cursor Connection Total number of rows fetch by the client from a cursor created by a prepared statement.
rows_skipped_normal, rows_skipped_ps Connection Reserved for future use (currently not supported)
copy_on_write_saved, copy_on_write_performed Process With mysqlnd, variables returned by the extensions point into mysqlnd internal network result buffers. If you do not change the variables, fetched data will be kept only once in memory. If you change the variables, mysqlnd has to perform a copy-on-write to protect the internal network result buffers from being changed. With the MariaDB Client Library you always hold fetched data twice in memory. Once in the internal MariaDB Client Library buffers and once in the variables returned by the extensions. In theory mysqlnd can save up to 40% memory. However, note that the memory saving cannot be measured using memory_get_usage.
explicit_free_result, implicit_free_result Connection, Process (only during prepared statement cleanup) Total number of freed result sets. The free is always considered explicit but for result sets created by an init command, for example, mysqli_options(MYSQLI_INIT_COMMAND , ...)
proto_text_fetched_null, proto_text_fetched_bit, proto_text_fetched_tinyint proto_text_fetched_short, proto_text_fetched_int24, proto_text_fetched_int proto_text_fetched_bigint, proto_text_fetched_decimal, proto_text_fetched_float proto_text_fetched_double, proto_text_fetched_date, proto_text_fetched_year proto_text_fetched_time, proto_text_fetched_datetime, proto_text_fetched_timestamp proto_text_fetched_string, proto_text_fetched_blob, proto_text_fetched_enum proto_text_fetched_set, proto_text_fetched_geometry, proto_text_fetched_other Connection Total number of columns of a certain type fetched from a normal query (MySQL text protocol). Mapping from C API / MariaDB meta data type to statistics name:
  • MYSQL_TYPE_NULL - proto_text_fetched_null
  • MYSQL_TYPE_BIT - proto_text_fetched_bit
  • MYSQL_TYPE_TINY - proto_text_fetched_tinyint
  • MYSQL_TYPE_SHORT - proto_text_fetched_short
  • MYSQL_TYPE_INT24 - proto_text_fetched_int24
  • MYSQL_TYPE_LONG - proto_text_fetched_int
  • MYSQL_TYPE_LONGLONG - proto_text_fetched_bigint
  • MYSQL_TYPE_DECIMAL, MYSQL_TYPE_NEWDECIMAL - proto_text_fetched_decimal
  • MYSQL_TYPE_FLOAT - proto_text_fetched_float
  • MYSQL_TYPE_DOUBLE - proto_text_fetched_double
  • MYSQL_TYPE_DATE, MYSQL_TYPE_NEWDATE - proto_text_fetched_date
  • MYSQL_TYPE_YEAR - proto_text_fetched_year
  • MYSQL_TYPE_TIME - proto_text_fetched_time
  • MYSQL_TYPE_DATETIME - proto_text_fetched_datetime
  • MYSQL_TYPE_TIMESTAMP - proto_text_fetched_timestamp
  • MYSQL_TYPE_STRING, MYSQL_TYPE_VARSTRING, MYSQL_TYPE_VARCHAR - proto_text_fetched_string
  • MYSQL_TYPE_TINY_BLOB, MYSQL_TYPE_MEDIUM_BLOB, MYSQL_TYPE_LONG_BLOB, MYSQL_TYPE_BLOB - proto_text_fetched_blob
  • MYSQL_TYPE_ENUM - proto_text_fetched_enum
  • MYSQL_TYPE_SET - proto_text_fetched_set
  • MYSQL_TYPE_GEOMETRY - proto_text_fetched_geometry
  • Any MYSQL_TYPE_* not listed before (there should be none) - proto_text_fetched_other

Note that the MYSQL_*-type constants may not be associated with the very same SQL column types in every version of MySQL.

proto_binary_fetched_null, proto_binary_fetched_bit, proto_binary_fetched_tinyint proto_binary_fetched_short, proto_binary_fetched_int24, proto_binary_fetched_int, proto_binary_fetched_bigint, proto_binary_fetched_decimal, proto_binary_fetched_float, proto_binary_fetched_double, proto_binary_fetched_date, proto_binary_fetched_year, proto_binary_fetched_time, proto_binary_fetched_datetime, proto_binary_fetched_timestamp, proto_binary_fetched_string, proto_binary_fetched_blob, proto_binary_fetched_enum, proto_binary_fetched_set, proto_binary_fetched_geometry, proto_binary_fetched_other Connection Total number of columns of a certain type fetched from a prepared statement (MySQL binary protocol). For type mapping see proto_text_* described in the preceding text.

Connection

Statistic Scope Description Notes
connect_success, connect_failure Connection Total number of successful / failed connection attempt. Reused connections and all other kinds of connections are included.
reconnect Process Total number of (real_)connect attempts made on an already opened connection handle. The code sequence $link = new mysqli(...); $link->real_connect(...) will cause a reconnect. But $link = new mysqli(...); $link->connect(...) will not because $link->connect(...) will explicitly close the existing connection before a new connection is established.
pconnect_success Connection Total number of successful persistent connection attempts. Note that connect_success holds the sum of successful persistent and non-persistent connection attempts. The number of successful non-persistent connection attempts is connect_success - pconnect_success.
active_connections Connection Total number of active persistent and non-persistent connections.
active_persistent_connections Connection Total number of active persistent connections. The total number of active non-persistent connections is active_connections - active_persistent_connections.
explicit_close Connection Total number of explicitly closed connections (ext/mysqli only). Examples of code snippets that cause an explicit close : 
$link = new mysqli(...); $link->close(...)
$link = new mysqli(...); $link->connect(...)
implicit_close Connection Total number of implicitly closed connections (ext/mysqli only). Examples of code snippets that cause an implicit close :
  • $link = new mysqli(...); $link->real_connect(...)
  • unset($link)
  • Persistent connection: pooled connection has been created with real_connect and there may be unknown options set - close implicitly to avoid returning a connection with unknown options
  • Persistent connection: ping/change_user fails and ext/mysqli closes the connection
  • end of script execution: close connections that have not been closed by the user
disconnect_close Connection Connection failures indicated by the C API call mysql_real_connect during an attempt to establish a connection. It is called disconnect_close because the connection handle passed to the C API call will be closed.
in_middle_of_command_close Process A connection has been closed in the middle of a command execution (outstanding result sets not fetched, after sending a query and before retrieving an answer, while fetching data, while transferring data with LOAD DATA). Unless you use asynchronous queries this should only happen if your script stops unexpectedly and PHP shuts down the connections for you.
init_command_executed_count Connection Total number of init command executions, for example, mysqli_options(MYSQLI_INIT_COMMAND , ...). The number of successful executions is init_command_executed_count - init_command_failed_count.
init_command_failed_count Connection Total number of failed init commands.

COM_* Commands

Statistic Scope Description Notes
com_quit, com_init_db, com_query, com_field_list, com_create_db, com_drop_db, com_refresh, com_shutdown, com_statistics, com_process_info, com_connect, com_process_kill, com_debug, com_ping, com_time, com_delayed_insert, com_change_user, com_binlog_dump, com_table_dump, com_connect_out, com_register_slave, com_stmt_prepare, com_stmt_execute, com_stmt_send_long_data, com_stmt_close, com_stmt_reset, com_stmt_set_option, com_stmt_fetch, com_daemon Connection Total number of attempts to send a certain COM_* command from PHP to MariaDB. The statistics are incremented after checking the line and immediately before sending the corresponding MariaDB client server protocol packet. If mysqlnd fails to send the packet over the wire the statistics will not be decremented. In case of a failure mysqlnd emits a PHP warning "Error while sending %s packet. PID=%d."

Usage examples:

  • Check if PHP sends certain commands to MySQL, for example, check if a client sends COM_PROCESS_KILL
  • Calculate the average number of prepared statement executions by comparing COM_EXECUTE with COM_PREPARE
  • Check if PHP has run any non-prepared SQL statements by checking if COM_QUERY is zero
  • Identify PHP scripts that run an excessive number of SQL statements by checking COM_QUERY and COM_EXECUTE

Miscellaneous

Statistic Scope Description Notes
explicit_stmt_close, implicit_stmt_close Process Total number of close prepared statements. A close is always considered explicit but for a failed prepare.
mem_emalloc_count, mem_emalloc_ammount, mem_ecalloc_count, mem_ecalloc_ammount, mem_erealloc_count, mem_erealloc_ammount, mem_efree_count, mem_malloc_count, mem_malloc_ammount, mem_calloc_count, mem_calloc_ammount, mem_realloc_count, mem_realloc_ammount, mem_free_count Process Memory management calls. Development only.
command_buffer_too_small Connection Number of network command buffer extensions while sending commands from PHP to MariaDB. mysqlnd allocates an internal command/network buffer of mysqlnd.net_cmd_buffer_size (php.ini) bytes for every connection. If a MariaDB Client Server protocol command, for example, COM_QUERY (normal query), does not fit into the buffer, mysqlnd will grow the buffer to what is needed for sending the command. Whenever the buffer gets extended for one connection command_buffer_too_small will be incremented by one.

If mysqlnd has to grow the buffer beyond its initial size of mysqlnd.net_cmd_buffer_size (php.ini) bytes for almost every connection, you should consider to increase the default size to avoid re-allocations.

The default buffer size is 2048 bytes in PHP 5.3.0. In future versions the default will be 4kB or larger. The default can changed either through the php.ini setting mysqlnd.net_cmd_buffer_size or using mysqli_options(MYSQLI_OPT_NET_CMD_BUFFER_SIZE, int size).

It is recommended to set the buffer size to no less than 4096 bytes because mysqlnd also uses it when reading certain communication packet from MySQL. In PHP 5.3.0, mysqlnd will not grow the buffer if MariaDB sends a packet that is larger than the current size of the buffer. As a consequence mysqlnd is unable to decode the packet and the client application will get an error. There are only two situations when the packet can be larger than the 2048 bytes default of mysqlnd.net_cmd_buffer_size in PHP 5.3.0: the packet transports a very long error message or the packet holds column meta data from COM_LIST_FIELD (mysql_list_fields) and the meta data comes from a string column with a very long default value (>1900 bytes). No bug report on this exists - it should happen rarely.

As of PHP 5.3.2 mysqlnd does not allow setting buffers smaller than 4096 bytes.

connection_reused

Notes

This section provides a collection of miscellaneous notes on MariaDB Native Driver usage.

MySQL Native Driver Plugin API

A comparison of mysqlnd plugins with MariaDB Proxy
Obtaining the mysqlnd plugin API
MySQL Native Driver Plugin Architecture
The mysqlnd plugin API
Getting started building a mysqlnd plugin

The MariaDB Native Driver Plugin API is a feature of MariaDB Native Driver, or mysqlnd. Mysqlnd plugins operate in the layer between PHP applications and the MariaDB server. This is comparable to MariaDB Proxy. MariaDB Proxy operates on a layer between any MariaDB client application, for example, a PHP application and, the MariaDB server. Mysqlnd plugins can undertake typical MariaDB Proxy tasks such as load balancing, monitoring and performance optimizations. Due to the different architecture and location, mysqlnd plugins do not have some of MariaDB Proxy's disadvantages. For example, with plugins, there is no single point of failure, no dedicated proxy server to deploy, and no new programming language to learn (Lua).

A mysqlnd plugin can be thought of as an extension to mysqlnd. Plugins can intercept the majority of mysqlnd functions. The mysqlnd functions are called by the PHP MariaDB extensions such as ext/mysql, ext/mysqli, and PDO_MYSQL. As a result, it is possible for a mysqlnd plugin to intercept all calls made to these extensions from the client application.

Internal mysqlnd function calls can also be intercepted, or replaced. There are no restrictions on manipulating mysqlnd internal function tables. It is possible to set things up so that when certain mysqlnd functions are called by the extensions that use mysqlnd, the call is directed to the appropriate function in the mysqlnd plugin. The ability to manipulate mysqlnd internal function tables in this way allows maximum flexibility for plugins.

Mysqlnd plugins are in fact PHP Extensions, written in C, that use the mysqlnd plugin API (which is built into MariaDB Native Driver, mysqlnd). Plugins can be made 100% transparent to PHP applications. No application changes are needed because plugins operate on a different layer. The mysqlnd plugin can be thought of as operating in a layer below mysqlnd.

The following list represents some possible applications of mysqlnd plugins.

MySQL Native Driver Plugins Available

There are a number of mysqlnd plugins already available. These include:

A comparison of mysqlnd plugins with MariaDB Proxy

Mysqlnd plugins and MariaDB Proxy are different technologies using different approaches. Both are valid tools for solving a variety of common tasks such as load balancing, monitoring, and performance enhancements. An important difference is that MariaDB Proxy works with all MariaDB clients, whereas mysqlnd plugins are specific to PHP applications.

As a PHP Extension, a mysqlnd plugin gets installed on the PHP application server, along with the rest of PHP. MariaDB Proxy can either be run on the PHP application server or can be installed on a dedicated machine to handle multiple PHP application servers.

Deploying MariaDB Proxy on the application server has two advantages:

  1. No single point of failure
  2. Easy to scale out (horizontal scale out, scale by client)

MySQL Proxy (and mysqlnd plugins) can solve problems easily which otherwise would have required changes to existing applications.

However, MariaDB Proxy does have some disadvantages:

MySQL Proxy can be customized with C and Lua programming. Lua is the preferred scripting language of MariaDB Proxy. For most PHP experts Lua is a new language to learn. A mysqlnd plugin can be written in C. It is also possible to write plugins in PHP using PECL/mysqlnd_uh.

MySQL Proxy runs as a daemon - a background process. MariaDB Proxy can recall earlier decisions, as all state can be retained. However, a mysqlnd plugin is bound to the request-based lifecycle of PHP. MariaDB Proxy can also share one-time computed results among multiple application servers. A mysqlnd plugin would need to store data in a persistent medium to be able to do this. Another daemon would need to be used for this purpose, such as Memcache. This gives MariaDB Proxy an advantage in this case.

MySQL Proxy works on top of the wire protocol. With MariaDB Proxy you have to parse and reverse engineer the MariaDB Client Server Protocol. Actions are limited to those that can be achieved by manipulating the communication protocol. If the wire protocol changes (which happens very rarely) MariaDB Proxy scripts would need to be changed as well.

Mysqlnd plugins work on top of the C API, which mirrors the libmysql client and Connector/C APIs. This C API is basically a wrapper around the MariaDB Client Server protocol, or wire protocol, as it is sometimes called. You can intercept all C API calls. PHP makes use of the C API, therefore you can hook all PHP calls, without the need to program at the level of the wire protocol.

Mysqlnd implements the wire protocol. Plugins can therefore parse, reverse engineer, manipulate and even replace the communication protocol. However, this is usually not required.

As plugins allow you to create implementations that use two levels (C API and wire protocol), they have greater flexibility than MariaDB Proxy. If a mysqlnd plugin is implemented using the C API, any subsequent changes to the wire protocol do not require changes to the plugin itself.

Obtaining the mysqlnd plugin API

The mysqlnd plugin API is simply part of the MariaDB Native Driver PHP extension, ext/mysqlnd. Development started on the mysqlnd plugin API in December 2009. It is developed as part of the PHP source repository, and as such is available to the public either via SVN, or through source snapshot downloads.

The following table shows PHP versions and the corresponding mysqlnd version contained within.

PHP Version MySQL Native Driver version
5.3.0 5.0.5
5.3.1 5.0.5
5.3.2 5.0.7
5.3.3 5.0.7
5.3.4 5.0.7

Plugin developers can determine the mysqlnd version through accessing MYSQLND_VERSION, which is a string of the format "mysqlnd 5.0.7-dev - 091210 - $Revision: 300535", or through MYSQLND_VERSION_ID, which is an integer such as 50007. Developers can calculate the version number as follows:

Version (part) Example
Major*10000 5*10000 = 50000
Minor*100 0*100 = 0
Patch 7 = 7
MYSQLND_VERSION_ID 50007

During development, developers should refer to the mysqlnd version number for compatibility and version tests, as several iterations of mysqlnd could occur during the lifetime of a PHP development branch with a single PHP version number.

MySQL Native Driver Plugin Architecture

This section provides an overview of the mysqlnd plugin architecture.

MySQL Native Driver Overview

Before developing mysqlnd plugins, it is useful to know a little of how mysqlnd itself is organized. Mysqlnd consists of the following modules:

Modules Statistics mysqlnd_statistics.c
Connection mysqlnd.c
Resultset mysqlnd_result.c
Resultset Metadata mysqlnd_result_meta.c
Statement mysqlnd_ps.c
Network mysqlnd_net.c
Wire protocol mysqlnd_wireprotocol.c

C Object Oriented Paradigm

At the code level, mysqlnd uses a C pattern for implementing object orientation.

In C you use a struct to represent an object. Members of the struct represent object properties. Struct members pointing to functions represent methods.

Unlike with other languages such as C++ or Java, there are no fixed rules on inheritance in the C object oriented paradigm. However, there are some conventions that need to be followed that will be discussed later.

The PHP Life Cycle

When considering the PHP life cycle there are two basic cycles:

When the PHP engine starts up it will call the module initialization (MINIT) function of each registered extension. This allows each module to setup variables and allocate resources that will exist for the lifetime of the PHP engine process. When the PHP engine shuts down it will call the module shutdown (MSHUTDOWN) function of each extension.

During the lifetime of the PHP engine it will receive a number of requests. Each request constitutes another life cycle. On each request the PHP engine will call the request initialization function of each extension. The extension can perform any variable setup and resource allocation required for request processing. As the request cycle ends the engine calls the request shutdown (RSHUTDOWN) function of each extension so the extension can perform any cleanup required.

How a plugin works

A mysqlnd plugin works by intercepting calls made to mysqlnd by extensions that use mysqlnd. This is achieved by obtaining the mysqlnd function table, backing it up, and replacing it by a custom function table, which calls the functions of the plugin as required.

The following code shows how the mysqlnd function table is replaced: 

/* a place to store orginal function table */
struct st_mysqlnd_conn_methods org_methods;
void minit_register_hooks(TSRMLS_D) {
 /* active function table */
 struct st_mysqlnd_conn_methods * current_methods
 = mysqlnd_conn_get_methods();
 /* backup original function table */
 memcpy(&org_methods, current_methods,
 sizeof(struct st_mysqlnd_conn_methods);
 /* install new methods */
 current_methods->query = MYSQLND_METHOD(my_conn_class, query);
}

Connection function table manipulations must be done during Module Initialization (MINIT). The function table is a global shared resource. In an multi-threaded environment, with a TSRM build, the manipulation of a global shared resource during the request processing will almost certainly result in conflicts.Note

Do not use any fixed-size logic when manipulating the mysqlnd function table: new methods may be added at the end of the function table. The function table may change at any time in the future.

Calling parent methods

If the original function table entries are backed up, it is still possible to call the original function table entries - the parent methods.

In some cases, such as for Connection::stmt_init(), it is vital to call the parent method prior to any other activity in the derived method. 

MYSQLND_METHOD(my_conn_class, query)(MYSQLND *conn,
 const char *query, unsigned int query_len TSRMLS_DC) {
 php_printf('my_conn_class::query(query = %s)\n', query);
 query = 'SELECT 'query rewritten' FROM DUAL';
 query_len = strlen(query);
 return org_methods.query(conn, query, query_len); /* return with call to parent */
}

Extending properties

A mysqlnd object is represented by a C struct. It is not possible to add a member to a C struct at run time. Users of mysqlnd objects cannot simply add properties to the objects.

Arbitrary data (properties) can be added to a mysqlnd objects using an appropriate function of the mysqlnd_plugin_get_plugin_<object>_data() family. When allocating an object mysqlnd reserves space at the end of the object to hold a void * pointer to arbitrary data. mysqlnd reserves space for one void * pointer per plugin.

The following table shows how to calculate the position of the pointer for a specific plugin:

Memory address Contents
0 Beginning of the mysqlnd object C struct
n End of the mysqlnd object C struct
n + (m x sizeof(void*)) void* to object data of the m-th plugin

If you plan to subclass any of the mysqlnd object constructors, which is allowed, you must keep this in mind!

The following code shows extending properties: 

/* any data we want to associate */
typedef struct my_conn_properties {
 unsigned long query_counter;
} MY_CONN_PROPERTIES;
/* plugin id */
unsigned int my_plugin_id;
void minit_register_hooks(TSRMLS_D) {
 /* obtain unique plugin ID */
 my_plugin_id = mysqlnd_plugin_register();
 /* snip - see Extending Connection: methods */
}
static MY_CONN_PROPERTIES** get_conn_properties(const MYSQLND *conn TSRMLS_DC) {
 MY_CONN_PROPERTIES** props;
 props = (MY_CONN_PROPERTIES**)mysqlnd_plugin_get_plugin_connection_data(
 conn, my_plugin_id);
 if (!props || !(*props)) {
 *props = mnd_pecalloc(1, sizeof(MY_CONN_PROPERTIES), conn->persistent);
 (*props)->query_counter = 0;
 }
 return props;
}

The plugin developer is responsible for the management of plugin data memory.

Use of the mysqlnd memory allocator is recommended for plugin data. These functions are named using the convention: mnd_*loc(). The mysqlnd allocator has some useful features, such as the ability to use a debug allocator in a non-debug build.

When and how to subclass

When to subclass? Each instance has its own private function table? How to subclass?
Connection (MYSQLND) MINIT No mysqlnd_conn_get_methods()
Resultset (MYSQLND_RES) MINIT or later Yes mysqlnd_result_get_methods() or object method function table manipulation
Resultset Meta (MYSQLND_RES_METADATA) MINIT No mysqlnd_result_metadata_get_methods()
Statement (MYSQLND_STMT) MINIT No mysqlnd_stmt_get_methods()
Network (MYSQLND_NET) MINIT or later Yes mysqlnd_net_get_methods() or object method function table manipulation
Wire protocol (MYSQLND_PROTOCOL) MINIT or later Yes mysqlnd_protocol_get_methods() or object method function table manipulation

You must not manipulate function tables at any time later than MINIT if it is not allowed according to the above table.

Some classes contain a pointer to the method function table. All instances of such a class will share the same function table. To avoid chaos, in particular in threaded environments, such function tables must only be manipulated during MINIT.

Other classes use copies of a globally shared function table. The class function table copy is created together with the object. Each object uses its own function table. This gives you two options: you can manipulate the default function table of an object at MINIT, and you can additionally refine methods of an object without impacting other instances of the same class.

The advantage of the shared function table approach is performance. There is no need to copy a function table for each and every object.

Constructors

Allocation, construction, reset Can be modified? Caller
Connection (MYSQLND) mysqlnd_init() No mysqlnd_connect()
Resultset(MYSQLND_RES) Allocation:
  • Connection::result_init()

Reset and re-initialized during:

  • Result::use_result()
  • Result::store_result
Yes, but call parent!
  • Connection::list_fields()
  • Statement::get_result()
  • Statement::prepare() (Metadata only)
  • Statement::resultMetaData()
Resultset Meta (MYSQLND_RES_METADATA) Connection::result_meta_init() Yes, but call parent! Result::read_result_metadata()
Statement (MYSQLND_STMT) Connection::stmt_init() Yes, but call parent! Connection::stmt_init()
Network (MYSQLND_NET) mysqlnd_net_init() No Connection::init()
Wire protocol (MYSQLND_PROTOCOL) mysqlnd_protocol_init() No Connection::init()

It is strongly recommended that you do not entirely replace a constructor. The constructors perform memory allocations. The memory allocations are vital for the mysqlnd plugin API and the object logic of mysqlnd. If you do not care about warnings and insist on hooking the constructors, you should at least call the parent constructor before doing anything in your constructor.

Regardless of all warnings, it can be useful to subclass constructors. Constructors are the perfect place for modifying the function tables of objects with non-shared object tables, such as Resultset, Network, Wire Protocol.

Destruction

Derived method must call parent? Destructor
Connection yes, after method execution free_contents(), end_psession()
Resultset yes, after method execution free_result()
Resultset Meta yes, after method execution free()
Statement yes, after method execution dtor(), free_stmt_content()
Network yes, after method execution free()
Wire protocol yes, after method execution free()

The destructors are the appropriate place to free properties, mysqlnd_plugin_get_plugin_<object>_data().

The listed destructors may not be equivalent to the actual mysqlnd method freeing the object itself. However, they are the best possible place for you to hook in and free your plugin data. As with constructors you may replace the methods entirely but this is not recommended. If multiple methods are listed in the above table you will need to hook all of the listed methods and free your plugin data in whichever method is called first by mysqlnd.

The recommended method for plugins is to simply hook the methods, free your memory and call the parent implementation immediately following this.Caution

Due to a bug in PHP versions 5.3.0 to 5.3.3, plugins do not associate plugin data with a persistent connection. This is because ext/mysql and ext/mysqli do not trigger all the necessary mysqlnd end_psession() method calls and the plugin may therefore leak memory. This has been fixed in PHP 5.3.4.

The mysqlnd plugin API

The following is a list of functions provided in the mysqlnd plugin API:

There is no formal definition of what a plugin is and how a plugin mechanism works.

Components often found in plugins mechanisms are:

The mysqlnd plugin concept employs these features, and additionally enjoys an open architecture.

No Restrictions

A plugin has full access to the inner workings of mysqlnd. There are no security limits or restrictions. Everything can be overwritten to implement friendly or hostile algorithms. It is recommended you only deploy plugins from a trusted source.

As discussed previously, plugins can use pointers freely. These pointers are not restricted in any way, and can point into another plugin's data. Simple offset arithmetic can be used to read another plugin's data.

It is recommended that you write cooperative plugins, and that you always call the parent method. The plugins should always cooperate with mysqlnd itself.

Issues: an example of chaining and cooperation

Extension mysqlnd.query() pointer call stack if calling parent
ext/mysqlnd mysqlnd.query() mysqlnd.query
ext/mysqlnd_cache mysqlnd_cache.query()
  1. mysqlnd_cache.query()
  2. mysqlnd.query
ext/mysqlnd_monitor mysqlnd_monitor.query()
  1. mysqlnd_monitor.query()
  2. mysqlnd_cache.query()
  3. mysqlnd.query

In this scenario, a cache (ext/mysqlnd_cache) and a monitor (ext/mysqlnd_monitor) plugin are loaded. Both subclass Connection::query(). Plugin registration happens at MINIT using the logic shown previously. PHP calls extensions in alphabetical order by default. Plugins are not aware of each other and do not set extension dependencies.

By default the plugins call the parent implementation of the query method in their derived version of the method.

PHP Extension Recap

This is a recap of what happens when using an example plugin, ext/mysqlnd_plugin, which exposes the mysqlnd C plugin API to PHP:

Getting started building a mysqlnd plugin

It is important to remember that a mysqlnd plugin is itself a PHP extension.

The following code shows the basic structure of the MINIT function that will be used in the typical mysqlnd plugin: 

/* my_php_mysqlnd_plugin.c */
 static PHP_MINIT_FUNCTION(mysqlnd_plugin) {
 /* globals, ini entries, resources, classes */
 /* register mysqlnd plugin */
 mysqlnd_plugin_id = mysqlnd_plugin_register();
 conn_m = mysqlnd_get_conn_methods();
 memcpy(org_conn_m, conn_m,
 sizeof(struct st_mysqlnd_conn_methods));
 conn_m->query = MYSQLND_METHOD(mysqlnd_plugin_conn, query);
 conn_m->connect = MYSQLND_METHOD(mysqlnd_plugin_conn, connect);
}

/* my_mysqlnd_plugin.c */
 enum_func_status MYSQLND_METHOD(mysqlnd_plugin_conn, query)(/* ... */) {
 /* ... */
}
enum_func_status MYSQLND_METHOD(mysqlnd_plugin_conn, connect)(/* ... */) {
 /* ... */
}

Task analysis: from C to userspace 

 class proxy extends mysqlnd_plugin_connection {
 public function connect($host, ...) { .. }
}
mysqlnd_plugin_set_conn_proxy(new proxy());

Process:

  1. PHP: user registers plugin callback
  2. PHP: user calls any PHP MariaDB API to connect to MySQL
  3. C: ext/*mysql* calls mysqlnd method
  4. C: mysqlnd ends up in ext/mysqlnd_plugin
  5. C: ext/mysqlnd_plugin
    1. Calls userspace callback
    2. Or orginal mysqlnd method, if userspace callback not set

You need to carry out the following:

  1. Write a class 'mysqlnd_plugin_connection' in C
  2. Accept and register proxy object through 'mysqlnd_plugin_set_conn_proxy()'
  3. Call userspace proxy methods from C (optimization - zend_interfaces.h)

Userspace object methods can either be called using call_user_function() or you can operate at a level closer to the Zend Engine and use zend_call_method().

Optimization: calling methods from C using zend_call_method

The following code snippet shows the prototype for the zend_call_method function, taken from zend_interfaces.h. 

 ZEND_API zval* zend_call_method(
 zval **object_pp, zend_class_entry *obj_ce,
 zend_function **fn_proxy, char *function_name,
 int function_name_len, zval **retval_ptr_ptr,
 int param_count, zval* arg1, zval* arg2 TSRMLS_DC
);

Zend API supports only two arguments. You may need more, for example: 

 enum_func_status (*func_mysqlnd_conn__connect)(
 MYSQLND *conn, const char *host,
 const char * user, const char * passwd,
 unsigned int passwd_len, const char * db,
 unsigned int db_len, unsigned int port,
 const char * socket, unsigned int mysql_flags TSRMLS_DC
);

To get around this problem you will need to make a copy of zend_call_method() and add a facility for additional parameters. You can do this by creating a set of MY_ZEND_CALL_METHOD_WRAPPER macros.

Calling PHP userspace

This code snippet shows the optimized method for calling a userspace function from C: 

/* my_mysqlnd_plugin.c */
MYSQLND_METHOD(my_conn_class,connect)(
 MYSQLND *conn, const char *host /* ... */ TSRMLS_DC) {
 enum_func_status ret = FAIL;
 zval * global_user_conn_proxy = fetch_userspace_proxy();
 if (global_user_conn_proxy) {
 /* call userspace proxy */
 ret = MY_ZEND_CALL_METHOD_WRAPPER(global_user_conn_proxy, host, /*...*/);
 } else {
 /* or original mysqlnd method = do nothing, be transparent */
 ret = org_methods.connect(conn, host, user, passwd,
 passwd_len, db, db_len, port,
 socket, mysql_flags TSRMLS_CC);
 }
 return ret;
}

Calling userspace: simple arguments 

/* my_mysqlnd_plugin.c */
 MYSQLND_METHOD(my_conn_class,connect)(
 /* ... */, const char *host, /* ...*/) {
 /* ... */
 if (global_user_conn_proxy) {
 /* ... */
 zval* zv_host;
 MAKE_STD_ZVAL(zv_host);
 ZVAL_STRING(zv_host, host, 1);
 MY_ZEND_CALL_METHOD_WRAPPER(global_user_conn_proxy, zv_retval, zv_host /*, ...*/);
 zval_ptr_dtor(&zv_host);
 /* ... */
 }
 /* ... */
}

Calling userspace: structs as arguments 

/* my_mysqlnd_plugin.c */
MYSQLND_METHOD(my_conn_class, connect)(
 MYSQLND *conn, /* ...*/) {
 /* ... */
 if (global_user_conn_proxy) {
 /* ... */
 zval* zv_conn;
 ZEND_REGISTER_RESOURCE(zv_conn, (void *)conn, le_mysqlnd_plugin_conn);
 MY_ZEND_CALL_METHOD_WRAPPER(global_user_conn_proxy, zv_retval, zv_conn, zv_host /*, ...*/);
 zval_ptr_dtor(&zv_conn);
 /* ... */
 }
 /* ... */
}

The first argument of many mysqlnd methods is a C 'object'. For example, the first argument of the connect() method is a pointer to MYSQLND. The struct MYSQLND represents a mysqlnd connection object.

The mysqlnd connection object pointer can be compared to a standard I/O file handle. Like a standard I/O file handle a mysqlnd connection object shall be linked to the userspace using the PHP resource variable type.

From C to userspace and back 

 class proxy extends mysqlnd_plugin_connection {
 public function connect($conn, $host, ...) {
 /* 'pre' hook */
 printf('Connecting to host = '%s'\n', $host);
 debug_print_backtrace();
 return parent::connect($conn);
 }
 public function query($conn, $query) {
 /* 'post' hook */
 $ret = parent::query($conn, $query);
 printf('Query = '%s'\n', $query);
 return $ret;
 }
}
mysqlnd_plugin_set_conn_proxy(new proxy());

PHP users must be able to call the parent implementation of an overwritten method.

As a result of subclassing it is possible to refine only selected methods and you can choose to have 'pre' or 'post' hooks.

Buildin class: mysqlnd_plugin_connection::connect() 

/* my_mysqlnd_plugin_classes.c */
 PHP_METHOD('mysqlnd_plugin_connection', connect) {
 /* ... simplified! ... */
 zval* mysqlnd_rsrc;
 MYSQLND* conn;
 char* host; int host_len;
 if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, 'rs',
 &mysqlnd_rsrc, &host, &host_len) == FAILURE) {
 RETURN_NULL();
 }
 ZEND_FETCH_RESOURCE(conn, MYSQLND* conn, &mysqlnd_rsrc, -1,
 'Mysqlnd Connection', le_mysqlnd_plugin_conn);
 if (PASS == org_methods.connect(conn, host, /* simplified! */ TSRMLS_CC))
 RETVAL_TRUE;
 else
 RETVAL_FALSE;
}

MySQL Functions (PDO_MYSQL) (MySQL (PDO))

PDO_MYSQL DSN

PDO_MYSQL is a driver that implements the PHP Data Objects (PDO) interface to enable access from PHP to MariaDB 3.x, 4.x and 5.x databases.

PDO_MYSQL will take advantage of native prepared statement support present in MariaDB and higher. If you're using an older version of the mysql client libraries, PDO will emulate them for you.Warning

Beware: Some MariaDB table types (storage engines) do not support transactions. When writing transactional database code using a table type that does not support transactions, MariaDB will pretend that a transaction was initiated successfully. In addition, any DDL queries issued will implicitly commit any pending transactions.

Use --with-pdo-mysql[=DIR] to install the PDO MariaDB extension, where the optional [=DIR] is the MariaDB base install directory. If mysqlnd is passed as [=DIR], then the MariaDB native driver will be used.

Optionally, the --with-mysql-sock[=DIR] sets to location to the MariaDB unix socket pointer for all MariaDB extensions, including PDO_MYSQL. If unspecified, the default locations are searched.

Optionally, the --with-zlib-dir[=DIR] is used to set the path to the libz install prefix. 

$ ./configure --with-pdo-mysql --with-mysql-sock=/var/mysql/mysql.sock

SSL support is enabled using the appropriate PDO-MySQL constants, which is equivalent to calling the MySQL C API function mysql_ssl_set(). Also, SSL cannot be enabled with PDO::setAttribute because the connection already exists. See also the MariaDB documentation about connecting to MariaDB with SSL.

Table 20.27. Changelog

Version Description
5.4.0 MySQL client libraries 4.1 and below are no longer supported.
5.3.9 Added SSL support with mysqlnd and OpenSSL.
5.3.7 Added SSL support with libmysql and OpenSSL.

The constants below are defined by this driver, and will only be available when the extension has been either compiled into PHP or dynamically loaded at runtime. In addition, these driver-specific constants should only be used if you are using this driver. Using driver-specific attributes with another driver may result in unexpected behaviour. PDO::getAttribute may be used to obtain the PDO_ATTR_DRIVER_NAME attribute to check the driver, if your code can run against multiple drivers.

PDO::MYSQL_ATTR_USE_BUFFERED_QUERY (integer)

If this attribute is set to TRUE on a PDOStatement, the MariaDB driver will use the buffered versions of the MariaDB API. If you're writing portable code, you should use PDOStatement::fetchAll instead.

Example 20.204. Forcing queries to be buffered in mysql

<?php if ($db->getAttribute(PDO::ATTR_DRIVER_NAME) == 'mysql') {
 $stmt = $db->prepare('select * from foo',
 array(PDO::MYSQL_ATTR_USE_BUFFERED_QUERY => true));
} else {
 die('my application only works with mysql; I should use \$stmt->fetchAll() instead');
}
?>
PDO::MYSQL_ATTR_LOCAL_INFILE (integer)

Enable LOAD LOCAL INFILE.

Note, this constant can only be used in the driver_options array when constructing a new database handle.

PDO::MYSQL_ATTR_INIT_COMMAND (integer)

Command to execute when connecting to the MariaDB server. Will automatically be re-executed when reconnecting.

Note, this constant can only be used in the driver_options array when constructing a new database handle.

PDO::MYSQL_ATTR_READ_DEFAULT_FILE (integer)

Read options from the named option file instead of from my.cnf. This option is not available if mysqlnd is used, because mysqlnd does not read the mysql configuration files.

PDO::MYSQL_ATTR_READ_DEFAULT_GROUP (integer)

Read options from the named group from my.cnf or the file specified with MYSQL_READ_DEFAULT_FILE . This option is not available if mysqlnd is used, because mysqlnd does not read the mysql configuration files.

PDO::MYSQL_ATTR_MAX_BUFFER_SIZE (integer)

Maximum buffer size. Defaults to 1 MiB. This constant is not supported when compiled against mysqlnd.

PDO::MYSQL_ATTR_DIRECT_QUERY (integer)

Perform direct queries, don't use prepared statements.

PDO::MYSQL_ATTR_FOUND_ROWS (integer)

Return the number of found (matched) rows, not the number of changed rows.

PDO::MYSQL_ATTR_IGNORE_SPACE (integer)

Permit spaces after function names. Makes all functions names reserved words.

PDO::MYSQL_ATTR_COMPRESS (integer)

Enable network communication compression. This is not supported when compiled against mysqlnd.

PDO::MYSQL_ATTR_SSL_CA (integer)

The file path to the SSL certificate authority.

This exists as of PHP 5.3.7.

PDO::MYSQL_ATTR_SSL_CAPATH (integer)

The file path to the directory that contains the trusted SSL CA certificates, which are stored in PEM format.

This exists as of PHP 5.3.7.

PDO::MYSQL_ATTR_SSL_CERT (integer)

The file path to the SSL certificate.

This exists as of PHP 5.3.7.

PDO::MYSQL_ATTR_CIPHER (integer)

A list of one or more permissible ciphers to use for SSL encryption, in a format understood by OpenSSL. For example: DHE-RSA-AES256-SHA:AES128-SHA

This exists as of PHP 5.3.7.

PDO::MYSQL_ATTR_KEY (integer)

The file path to the SSL key.

This exists as of PHP 5.3.7.

The behaviour of these functions is affected by settings in php.ini.

Table 20.28. PDO_MYSQL Configuration Options

Name Default Changeable
pdo_mysql.default_socket '/tmp/mysql.sock' PHP_INI_SYSTEM
pdo_mysql.debug NULL PHP_INI_SYSTEM

For further details and definitions of the PHP_INI_* modes, see the http://www.php.net/manual/en/configuration.changes.modes.

Here's a short explanation of the configuration directives.

pdo_mysql.default_socket string

Sets a Unix domain socket. This value can either be set at compile time if a domain socket is found at configure. This ini setting is Unix only.

pdo_mysql.debug boolean

Enables debugging for PDO_MYSQL. This setting is only available when PDO_MYSQL is compiled against mysqlnd and in PDO debug mode.

PDO_MYSQL DSN

Description

The PDO_MYSQL Data Source Name (DSN) is composed of the following elements:

DSN prefix

The DSN prefix is mysql:.

host

The hostname on which the database server resides.

port

The port number where the database server is listening.

dbname

The name of the database.

unix_socket

The MariaDB Unix socket (shouldn't be used with host or port).

charset

The character set.

Prior to PHP 5.3.6, this element was silently ignored. The same behaviour can be partly replicated with the PDO::MYSQL_ATTR_INIT_COMMAND driver option, as the following example shows.Warning

The method in the below example can only be used with character sets that share the same lower 7 bit representation as ASCII, such as ISO-8859-1 and UTF-8. Users using character sets that have different representations (such as UTF-16 or Big5) must use the charset option provided in PHP 5.3.6 and later versions.

Example 20.205. Setting the connection character set to UTF-8 prior to PHP 5.3.6

<?php
$dsn = 'mysql:host=localhost;dbname=testdb';
$username = 'username';
$password = 'password';
$options = array(
 PDO::MYSQL_ATTR_INIT_COMMAND => 'SET NAMES utf8',
); 
$dbh = new PDO($dsn, $username, $password, $options);
?>

Changelog

Version Description
5.3.6 Prior to version 5.3.6, charset was ignored.

Examples

Example 20.206. PDO_MYSQL DSN examples

The following example shows a PDO_MYSQL DSN for connecting to MariaDB databases: 

mysql:host=localhost;dbname=testdb

More complete examples: 

mysql:host=localhost;port=3307;dbname=testdb mysql:unix_socket=/tmp/mysql.sock;dbname=testdb

Notes

Unix only:

When the host name is set to 'localhost', then the connection to the server is made thru a domain socket. If PDO_MYSQL is compiled against libmysql then the location of the socket file is at libmysql's compiled in location. If PDO_MYSQL is compiled against mysqlnd a default socket can be set thru the pdo_mysql.default_socket setting.

Connector/PHP

This documentation, and other publications, sometimes uses the term Connector/PHP. This term refers to the full set of MariaDB related functionality in PHP, which includes the three APIs that are described above, along with the mysqlnd core library and all of its plugins.

Common Problems with MariaDB and PHP

Enabling Both MariaDB and mysqli in PHP

If you're experiencing problems with enabling both the MariaDB and the mysqli extension when building PHP on Linux yourself, you should try the following procedure.

  1. Configure PHP like this: 

    ./configure --with-mysqli=/usr/bin/mysql_config --with-mysql=/usr
  2. Edit the Makefile and search for a line that starts with EXTRA_LIBS. It might look like this (all on one line): 
    EXTRA_LIBS = -lcrypt -lcrypt -lmysqlclient -lz -lresolv -lm -ldl -lnsl
-lxml2 -lz -lm -lxml2 -lz -lm -lmysqlclient -lz -lcrypt -lnsl -lm
-lxml2 -lz -lm -lcrypt -lxml2 -lz -lm -lcrypt

    Remove all duplicates, so that the line looks like this (all on one line): 

    EXTRA_LIBS = -lcrypt -lcrypt -lmysqlclient -lz -lresolv -lm -ldl -lnsl
-lxml2
  3. Build and install PHP: 
    make make install

MySQL Perl API

The Perl DBI module provides a generic interface for database access. You can write a DBI script that works with many different database engines without change. To use DBI with MySQL, install the following:

  1. The DBI module.
  2. The DBD::mysql module. This is the DataBase Driver (DBD) module for Perl.
  3. Optionally, the DBD module for any other type of database server you want to access.

Perl DBI is the recommended Perl interface. It replaces an older interface called mysqlperl, which should be considered obsolete.

These sections contain information about using Perl with MariaDB and writing MariaDB applications in Perl:

DBI information is available at the command line, online, or in printed form:

MySQL Python API

MySQLdb provides MariaDB support for Python, compliant with the Python DB API version 2.0. It can be found at http://sourceforge.net/projects/mysql-python/.

Guidelines for Python Developers

The following guidelines cover aspects of developing MariaDB applications that might not be immediately obvious to developers coming from a Python background:

MySQL Ruby APIs

The MySQL/Ruby API
The Ruby/MySQL API

Two APIs are available for Ruby programmers developing MariaDB applications:

For background and syntax information about the Ruby language, see Ruby Programming Language.

The MySQL/Ruby API

The MySQL/Ruby module provides access to MariaDB databases using Ruby through libmysql.

For information on installing the module, and the functions exposed, see MySQL/Ruby.

The Ruby/MySQL API

The Ruby/MySQL module provides access to MariaDB databases using Ruby through a native driver interface using the MariaDB network protocol.

For information on installing the module, and the functions exposed, see Ruby/MySQL.

MySQL Tcl API

MySQLtcl is a simple API for accessing a MariaDB database server from the Tcl programming language. It can be found at http://www.xdobry.de/mysqltcl/.

MySQL Eiffel Wrapper

Eiffel MariaDB is an interface to the MariaDB database server using the Eiffel programming language, written by Michael Ravits. It can be found at http://efsa.sourceforge.net/archive/ravits/mysql.htm.Copyright 1997, 2012, Oracle and/or its affiliates. All rights reserved. Legal Notices

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