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

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