CREATE PROCEDURE statement

ASA SQL Reference
SQL Statements

CREATE PROCEDURE statement

Description

Use this statement to create a procedure in the database.

Syntax 1

CREATE PROCEDURE [ owner.]procedure-name ( [ parameter, ... ] )
{   [ RESULT ( result-column, ... ) ]
    [ ON EXCEPTION RESUME ]
      compound-statement
   | AT location-string
   | EXTERNAL NAME library-call
   | [ DYNAMIC RESULT SETS integer-expression ]
     [ EXTERNAL NAME java-call LANGUAGE JAVA ]
    }

Syntax 2

CREATE PROCEDURE [ owner.]procedure-name ( [ parameter, ... ] )
compound-statement

parameter :
parameter_mode parameter-name data-type [ DEFAULT expression ]
| SQLCODE
| SQLSTATE

parameter_mode : IN | OUT | INOUT

result-column : column-name data-type

library-call :
'[operating-system:]function-name@library; ...'

operating-system :
Windows95 | WindowsNT | NetWare | UNIX

java-call :
'[package-name.]class-name.method-name method-signature'

method-signature :
([field-descriptor, ... ] ) return-descriptor

field-descriptor | return-descriptor :
Z | B | S | I | J | F | D | C | V | [descriptor | Lclass-name;

Parameters

CREATE PROCEDURE clause Parameter names must conform to the rules for other database identifiers such as column names. They must be a valid SQL data type (see SQL Data Types), and must be prefixed by one of the keywords IN, OUT or INOUT. The keywords have the following meanings:

IN The parameter is an expression that provides a value to the procedure.
OUT The parameter is a variable that could be given a value by the procedure.
INOUT The parameter is a variable that provides a value to the procedure, and could be given a new value by the procedure.

When procedures are executed using the CALL statement, 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.

RESULT clause The RESULT clause 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. Allowable data types are listed in SQL Data Types.

For more information on returning result sets from procedures, see Returning results from procedures.

Some procedures can more than one result set, with different numbers of columns, depending on how they are executed. For example, the following procedure returns two columns under some circumstances, and one in others.

CREATE PROCEDURE names( IN formal char(1))
BEGIN
   IF formal = 'n' THEN
      SELECT emp_fname
      FROM employee
   ELSE
      SELECT emp_lname,emp_fname
      FROM employee
   END IF
END

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

Embedded SQL You must DESCRIBE the procedure call after the cursor for the result set is opened, but before any rows are returned, in order to get the proper shape of result set. The CURSOR cursor-name clause on the DESCRIBE statement is required.
ODBC, OLE DB, ADO.NET Variable result-set procedures can be used by applications using these interfaces. The proper description of the result sets is carried out by the driver or provider.
Open Client applications Variable result-set procedures can be used by Open Client applications.

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

In order 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.

ON EXCEPTION RESUME clause This clause enables Transact-SQL -like error handling to be used within a Watcom-SQL syntax procedure.

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 the following:

IF
SELECT @variable =
CASE
LOOP
LEAVE
CONTINUE
CALL
EXECUTE
SIGNAL
RESIGNAL
DECLARE
SET VARIABLE

You should not use explicit error handling code with an ON EXCEPTION RESUME clause.

For more information, see ON_TSQL_ERROR option [compatibility].

EXTERNAL NAME clause A procedure using the EXTERNAL NAME clause is a wrapper around a call to an external library. A stored procedure using EXTERNAL NAME can have no other clauses following the parameter list. The library name may include the file extension, which is typically .dll on Windows, .so on UNIX, and .nlm on NetWare. In the absence of the extension, the software appends the platform-specific default file extension for libraries. On NetWare, if no NLM name is given, the NLM containing the symbol must already be loaded when the function is called.

For information about external library calls, see Calling external libraries from procedures.

AT location-string clause Create 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 filenames and extensions to be used in the database and owner fields.

For example, the following statement creates a proxy procedure (remotewho) that calls the dbo.sp_who procedure on the master database of the bostonase server:

CREATE PROCEDURE remotewho ()
AT 'bostonase.master.dbo.sp_who

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

For information on remote servers, see CREATE SERVER statement. For information on using remote procedures, see Using remote procedure calls (RPCs).

DYNAMIC RESULT SETS clause This clause is for use with procedures that are wrappers around Java methods. If the DYNAMIC RESULT SETS clause is not provided, it is assumed that the method returns no result set.

EXTERNAL NAME LANGUAGE JAVA clause A procedure that uses EXTERNAL NAME with a LANGUAGE JAVA clause is a wrapper around a Java method.

If the number of parameters is less than the number indicated in the method-signature then the difference must equal the number specified in DYNAMIC RESULT SETS, and each parameter in the method signature in excess of those in the procedure parameter list must have a method signature of [Ljava/SQL/ResultSet;.

A Java method signature is a compact character representation of the types of the parameters and the type of the return value. It is an error to put a space before the signature.

The field-descriptor and return-descriptor have the following meanings:

Field type	Java data type
B	byte
C	char
D	double
F	float
I	int
J	long
Lclass-name;	an instance of the class class-name. The class name must be fully qualified, and any dot in the name must be replaced by a /. For example, java/lang/String
S	short
V	void
Z	Boolean
[	use one for each dimension of an array

For example,

double some_method(
  boolean a,
  int b,
  java.math.BigDecimal c,
  byte [][] d,
  java.SQL.ResultSet[] rs ) {
}

would have the following signature:

'(ZILjava/math/BigDecimal;[[B[Ljava/SQL/ResultSet;)D'

For more information, see Returning result sets from Java methods.

Usage

The CREATE PROCEDURE statement creates a procedure in the database. Users with DBA authority can create procedures for other users by specifying an owner. A procedure is invoked with a CALL statement.

Permissions

Must have RESOURCE authority.

Must have DBA authority for external procedures or to create a procedure for another user.

Side effects

Automatic commit.

Standards and compatibility

SQL/92 Persistent Stored Module feature.
SQL/99 Persistent Stored Module feature.
Sybase The Transact-SQL CREATE PROCEDURE statement is different.
SQLJ The syntax extensions for Java result sets are as specified in the proposed SQLJ1 standard.

Examples

The following procedure uses 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 "DBA"."product"
   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

The following procedure uses a cursor and loops 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 company_name,
          CAST(sum(sales_order_items.quantity *
          product.unit_price) AS INTEGER) VALUE
      FROM customer
      LEFT OUTER JOIN sales_order
      LEFT OUTER JOIN sales_order_items
      LEFT OUTER JOIN product
      GROUP BY company_name;
   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

CREATE PROCEDURE statement

Description

Syntax 1

Syntax 2

Parameters

Usage

Permissions

Side effects

See also

Standards and compatibility

Examples