PLVexc: Exception Handling

The PLVexc (PL/Vision EXCeption handling) package provides generic and powerful exception-handling capabilities. See Exception Handling for details.

Package constants

• c_go CONSTANT CHAR(1) := 'C';
• Requests that your program continue (ignore the error). Explained in more detail below.
• c_recNgo CONSTANT CHAR(2) := 'RC';
• Requests that your program record the error and then continue. Explained in more detail below.
• c_stop CONSTANT CHAR(1) := 'H';
• Requests that your program be halted if this exception occurs. Explained in more detail below.
• c_recNstop CONSTANT CHAR(2) := 'RH';
• Requests that your program record the error and then halt. Explained in more detail below.

Package-based exceptions

• process_halted EXCEPTION;
• Package-specific exception raised when you request a "halt" action in the handler programs.
• no_such_table EXCEPTION;
• PRAGMA EXCEPTION_INIT (no_such_table, -942);
• Predefined system exception for error ORA-942. Saves other developers from dealing with the EXCEPTION_INIT pragma.
• snapshot_too_old EXCEPTION;
• PRAGMA EXCEPTION_INIT (snapshot_too_old, -1555);
• Predefined system exception for error ORA-1555. Saves other developers from dealing with the EXCEPTION_INIT pragma.

Logging exception-handling activity

• PROCEDURE log;
• Requests that whenever a PLVexc handler is called, a message is sent to the PL/Vision log.
• PROCEDURE nolog;
• Do not log the handling action when the exception is recorded and handled. with the COMMIT.
• FUNCTION logging RETURN BOOLEAN;
• Returns TRUE if currently logging PLVexc-based exception handling.

Displaying exceptions

• PROCEDURE show;
• Requests that error information be displayed to your screen using the p.l procedure.
• PROCEDURE noshow;
• Turns off display of the error information.
• FUNCTION showing RETURN BOOLEAN;
• Returns TRUE if PLVexc is currently showing errors.

Rolling back on exception

• PROCEDURE rblast;
• Requests that a rollback be issued to the most recent savepoint before writing error information to the log (the default).
• PROCEDURE rbdef;
• Requests that a rollback be issued to the default PLVlog savepoint before writing error information to the log (the default).
• PROCEDURE norb;
• Turns off issuing of rollback before logging of the error information.
• FUNCTION rb RETURN VARCHAR2;
• Returns TRUE if PLVexc is currently issuing a rollback.

Exception handlers

• PROCEDURE handle
• (context_in IN VARCHAR2,
• err_code_in IN INTEGER,
• handle_action_in IN VARCHAR2,
• msg_in IN VARCHAR2 := SQLERRM);
• Low-level, generic exception-handling program. This program is called by all other PLVexc handlers, which are overloaded for error number and message.
• PROCEDURE recNgo (msg_in IN VARCHAR2 := NULL);
• PROCEDURE recNgo (err_code_in IN INTEGER);
• High-level exception handler that records and then ignores the error.
• PROCEDURE go (msg_in IN VARCHAR2 := NULL);
• PROCEDURE go (err_code_in IN INTEGER);
• High-level exception handler that ignores the error, but gives you the opportunity to log or display the exception.
• PROCEDURE recNstop (msg_in IN VARCHAR2 := NULL);
• PROCEDURE recNstop (err_code_in IN INTEGER);
• High-level exception handler that records the error and then causes the current program to halt.
• PROCEDURE stop (msg_in IN VARCHAR2 := NULL);
• PROCEDURE stop (err_code_in IN INTEGER);
• High-level exception handler that causes the current program to halt.

Bailing out program execution

• PROCEDURE bailout;
• Starts the bailout process; the current exception will be propagated out of all exception sections that use PLVexc, regardless of the action handled.
• PROCEDURE nobailout;
• Turns off the bailout process. PLVexc will not propagate the exception past all PLVexc exception handlers.
• FUNCTION bailing_out RETURN BOOLEAN;
• Returns TRUE if PLVexc is currently set to bail out when it encounters a bailout error.
• PROCEDURE clear_bailouts;
• Registers a specific error number as a bailout error.

Managing the list of bailout errors

• PROCEDURE clear_bailouts;
• Clears the PLVexc list of bailout errors.
• PROCEDURE bailout_on (err_code_in IN INTEGER);
• Adds an error code to the list that PLVexc treats as bailout errors.
• PROCEDURE nobailout_on (err_code_in IN INTEGER);
• Removes an error code from the list that PLVexc treats as bailout errors.
• FUNCTION bailout_error (err_code_in IN INTEGER) RETURN BOOLEAN;
• Returns TRUE if the specified error is a bailout error.