MySQL Stored Procedure Programming

SQL Statements for Managing Stored Programs

This section summarizes the syntax of the statements used to create, modify, and remove stored programs from the database. This section provides only an overview; we’ll drill down into many of the details of these statements in other chapters.

CREATE PROCEDURE

The CREATE PROCEDURE statement—you guessed it—creates a stored procedure. The syntax for the statement is:

    CREATE PROCEDURE procedure_name ([parameter[,...])
        [LANGUAGE SQL]
        [ [NOT] DETERMINISTIC 
 ]
        [ {CONTAINS SQL|MODIFIES SQL DATA|READS SQL DATA|NO SQL} ]
        [SQL SECURITY {DEFINER|INVOKER} ]
        [COMMENT comment_string]procedure_statements

The procedure_name follows the normal conventions for the naming of database objects (see Chapter 3).

The parameter list consists of a comma-separated list of arguments that can be provided to the stored procedure. We spent quite a bit of time on parameters in Chapter 3, but to summarize, each parameter is of the form:

    [{IN|OUT|INOUT} ] parameter_name datatype

By default, parameters are of the IN type: this means that their values must be specified by the calling program and that any modifications made to the parameter in the stored program cannot be accessed from the calling program. OUT parameters, on the other hand, can be modified by the stored program, and the modified values can be retrieved from the calling program.

An INOUT parameter acts as both an IN and an OUT parameter: the calling program can supply a value and can see whatever changes are made ...