CREATE PROCEDURE Statement

To create external procedure interfaces, see CREATE PROCEDURE Statement (External Procedures).

Syntax

CREATE [ OR REPLACE | TEMPORARY ] PROCEDURE [ owner.]procedure-name ( [ parameter, …] ) { 
[ RESULT ( result-column, …) | NO RESULT SET ]  
[ SQL SECURITY { INVOKER | DEFINER } ] 
[ ON EXCEPTION RESUME ] compound statement | AT location-string

Parameters

• parameter – parameter_mode parameter-name data-type [ DEFAULT expression ] | SQLCODE | SQLSTATE
• parameter_mode – IN | OUT | INOUT
• result-column – column-name data-type

Examples

• Example 1 – Use a case statement to classify the results of a query:

  CREATE PROCEDURE ProductType (IN product_id INT, OUT type CHAR(10))
  BEGIN
    DECLARE prod_name CHAR(20) ;
    SELECT name INTO prod_name FROM "GROUPO"."Products"
    WHERE ID = product_id;
    CASE prod_name
    WHEN 'Tee Shirt' THEN
      SET type = 'Shirt'			
    WHEN 'Sweatshirt' THEN
      SET type = 'Shirt'
    WHEN 'Baseball Cap' THEN
      SET type = 'Hat'
    WHEN 'Visor' THEN
      SET type = 'Hat'
    WHEN 'Shorts' THEN
      SET type = 'Shorts'
    ELSE
      SET type = 'UNKNOWN'
    END CASE ;
  END

• Example 2 – Use a cursor and loop over the rows of the cursor to return a single value:

  CREATE PROCEDURE TopCustomer (OUT TopCompany CHAR(35), OUT TopValue INT)
  BEGIN
    DECLARE err_notfound EXCEPTION
   	FOR SQLSTATE '02000' ;
    DECLARE curThisCust CURSOR FOR
    SELECT CompanyName, CAST( 	  sum(SalesOrderItems.Quantity *
    Products.UnitPrice) AS INTEGER) VALUE
    FROM Customers
    LEFT OUTER JOIN SalesOrders
    LEFT OUTER JOIN SalesorderItems
    LEFT OUTER JOIN Products
    GROUP BY CompanyName ;
  
  
    DECLARE ThisValue INT ;
    DECLARE ThisCompany CHAR(35) ;
    SET TopValue = 0 ;
    OPEN curThisCust ;
    CustomerLoop:
    LOOP
      FETCH NEXT curThisCust
      INTO ThisCompany, ThisValue ;
      IF SQLSTATE = err_notfound THEN
        LEAVE CustomerLoop ;
      END IF ;
      IF ThisValue > TopValue THEN
        SET TopValue = ThisValue ;
        SET TopCompany = ThisCompany ;
        END IF ;
    END LOOP CustomerLoop ;
    CLOSE curThisCust ;
  END

Usage

CREATE PROCEDURE creates a procedure in the database. Users with the CREATE ANY OBJECT system privilege can create procedures for other users by specifying an owner. A procedure is invoked with a CALL statement.

CREATE PROCEDURE— You can create permanent or temporary (TEMPORARY) stored procedures. You can use PROC as a synonym for PROCEDURE.

Parameter names must conform to the rules for other database identifiers, such as column names, and must be a valid SQL data type. The keywords have the following meanings:

Parameters can be prefixed by one of the keywords IN, OUT or INOUT. If no keyword is specified, parameters are INOUT by default. The keywords have the following meanings:

When procedures are executed using CALL, not all parameters need to be specified. If a default value is provided in the CREATE PROCEDURE statement, missing parameters are assigned the default values. If an argument is not provided in the CALL statement, and no default is set, an error is given.

SQLSTATE and SQLCODE are special parameters that output the SQLSTATE or SQLCODE value when the procedure ends (they are OUT parameters). Whether or not a SQLSTATE and SQLCODE parameter is specified, the SQLSTATE and SQLCODE special values can always be checked immediately after a procedure call to test the return status of the procedure.

The SQLSTATE and SQLCODE special values are modified by the next SQL statement. Providing SQLSTATE or SQLCODE as procedure arguments allows the return code to be stored in a variable.

Specifying CREATE OR REPLACE PROCEDURE creates a new procedure, or replaces an existing procedure with the same name. This clause changes the definition of the procedure, but preserves existing permissions. You cannot use the OR REPLACE clause with temporary procedures. Also, an error is returned if the procedure being replaced is already in use.

Specifying CREATE TEMPORARY PROCEDURE means that the stored procedure is visible only by the connection that created it, and that it is automatically dropped when the connection is dropped. You can also explicitly drop temporary stored procedures. You cannot perform ALTER, GRANT, or REVOKE on them, and, unlike other stored procedures, temporary stored procedures are not recorded in the catalog or transaction log.

To drop the owner of a temporary procedure, drop the temporary procedure first.

You can create and drop temporary stored procedures when you are connected to a read-only database; they cannot be external procedures.

For example, the following temporary procedure drops the table called CustRank, if it exists. For this example, the procedure assumes that the table name is unique and can be referenced by the procedure creator without specifying the table owner:

CREATE TEMPORARY PROCEDURE drop_table( IN @TableName char(128) )
BEGIN
	IF EXISTS  ( SELECT 1 FROM SYS.SYSTAB WHERE
	table_name = @TableName ) 
	THEN EXECUTE IMMEDIATE 
	'DROP TABLE "' || @TableName || '"';
	MESSAGE 'Table "' || @TableName || 
	'" dropped' to client;
	END IF;
END;
CALL drop_table( 'CustRank' )

RESULT—Declares the number and type of columns in the result set. The parenthesized list following the RESULT keyword defines the result column names and types. This information is returned by the Embedded SQL DESCRIBE or by ODBC SQLDescribeCol when a CALL statement is being described. Allowed data types are listed in Reference: Building Blocks, Tables, and Procedures > SQL Data Types.

Some procedures can produce more than one result set, depending on how they are executed. For example, this procedure returns two columns under some circumstances, and one in others.

CREATE PROCEDURE names( IN formal char(1))
BEGIN
  IF formal = 'n' THEN
    SELECT GivenName 
    FROM Employees
  ELSE
    SELECT Surname,GivenName 
    FROM Employees
  END IF
END

Procedures with variable result sets must be written without a RESULT clause, or in Transact-SQL. Their use is subject to these limitations:

If your procedure returns only one result set, use a RESULT clause. The presence of this clause prevents ODBC and Open Client applications from describing the result set again after a cursor is open.

To handle multiple result sets, ODBC must describe the currently executing cursor, not the procedure’s defined result set. Therefore, ODBC does not always describe column names as defined in the RESULT clause of the procedure definition. To avoid this problem, use column aliases in the SELECT statement that generates the result set.

NO RESULT SET —Declares that this procedure returns no result set. This is useful when an external environment needs to know that a procedure does not return a result set.

SQL SECURITY—Defines whether the procedure is executed as the INVOKER (the user who is calling the procedure), or as the DEFINER (the user who owns the procedure). The default is DEFINER.

Extra memory is used when you specify SQL SECURITY INVOKER, because annotation must be done for each user that calls the procedure. Also, name resolution is performed as the invoker as well. Therefore, qualify all object names (tables, procedures, and so on) with their appropriate owner. For example, suppose user1 creates this procedure:

 CREATE PROCEDURE user1.myProcedure()
	RESULT( columnA INT )
	SQL SECURITY INVOKER
	BEGIN
		SELECT columnA FROM table1;
	END;

If user2 attempts to run this procedure and a table user2.table1 does not exist, a table lookup error results. Additionally, if a user2.table1 does exist, that table is used instead of the intended user1.table1. To prevent this situation, qualify the table reference in the statement (user1.table1, instead of just table1).

If you use ON EXCEPTION RESUME, the procedure takes an action that depends on the setting of the ON_TSQL_ERROR option. If ON_TSQL_ERROR is set to CONDITIONAL (which is the default) the execution continues if the next statement handles the error; otherwise, it exits.

Error-handling statements include:

Do not use explicit error-handling code with an ON EXCEPTION RESUME clause.

See ON_TSQL_ERROR Option [TSQL].

AT location-string—Creates a proxy stored procedure on the current database for a remote procedure specified by location-string. The AT clause supports the semicolon (;) as a field delimiter in location-string. If no semicolon is present, a period is the field delimiter. This allows file names and extensions to be used in the database and owner fields.

Remote procedures can return only up to 254 characters in output variables.

If a remote procedure can return a result set, even if it does not return one in all cases, then the local procedure definition must contain a RESULT clause.

For information on remote servers, see CREATE SERVER Statement.

Standards

Permissions

Watcom SQL or Transact SQL procedure to be owned by self – Requires CREATE PROCEDURE system privilege.