CREATE PROCEDURE Statement (External Procedures)

To create a SQL procedure, see CREATE PROCEDURE Statement .

Syntax

CREATE[ OR REPLACE ] PROCEDURE [ owner.]procedure-name ( [ parameter, …] ) 
[ RESULT ( result-column, …) | NO RESULT SET ]  
[  DYNAMIC RESULT SETS integer-expression ]
 [ SQL SECURITY { INVOKER | DEFINER } ] 
[ EXTERNAL NAME ‘external-call’ [ LANGUAGE environment-name ]

Parameters

• parameter: – parameter_mode parameter-name data-type [ DEFAULT expression ] | SQLCODE | SQLSTATE
• parameter_mode: – IN | OUT | INOUT
• result-column: – column-name data-type
• environment-name : – C_ESQL32 | C_ESQL64 | C_ODBC32 | C_ODBC64 | CLR | JAVA | PERL |  PHP

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

The body of a procedure consists of a compound statement. For information on compound statements, see BEGIN … END Statement.

CREATE PROCEDURE 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.

If a stored procedure returns a result set, it cannot also set output parameters or return a return value.

When referencing a temporary table from multiple procedures, a potential issue can arise if the temporary table definitions are inconsistent and statements referencing the table are cached.

See SQL Anywhere 11.0.1 > SQL Anywhere Server – SQL Usage > > Creating Databases > Working with database objects > Working with temporary tables > Referencing temporary tables within procedures.

CREATE PROCEDURE—You can create permanent stored procedures that call external or native procedures written in a variety of programming languages. You can use PROC as a synonym for PROCEDURE.

Parameter names must conform to the rules for other database identifiers such as column names. They must be a valid SQL data type. See Reference: Building Blocks, Tables, and Procedures > SQL Data Types.

Parameters can be prefixed with one of the keywords IN, OUT, or INOUT. If you do not specify one of these values, parameters are INOUT by default. The keywords mean:

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 OUT parameters that output the SQLSTATE or SQLCODE value when the procedure ends. 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 OR REPLACE (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. An error is returned if you attempt to replace a procedure that is already in use.

You cannot create TEMPORARY external call procedures.

For more information on returning result sets from procedures, see System Administration Guide: Volume 2 > Using Procedures and Batches.

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.

Procedures that call into Embedded SQL (LANGUAGE C_ESQL32, LANGUAGE C_ESQL64) or ODBC (LANGUAGE C_ODBC32, LANGUAGE C_ODBC64) external functions can return 0 or 1 result sets.

Procedures that call into Perl or PHP (LANGUAGE PERL, LANGUAGE PHP) external functions cannot return result sets. Procedures that call native functions loaded by the database server cannot return result sets.

Procedures that call into CLR or Java (LANGUAGE CLR, LANGUAGE JAVA) external functions can return 0, 1, or more result sets.

Some procedures can return more than one result set, with different numbers of columns, 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 be written 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.

See SQL Anywhere 11.01 > SQL Anywhere Server – SQL Usage > Stored Procedures and Triggers > Using procedures, triggers, and batches > Returning results from procedures.

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.

DYNAMIC RESULT SETS—Use this clause with LANGUAGE CLR and LANGUAGE JAVA calls. If the DYNAMIC RESULT SETS clause is not provided, it is assumed that the method returns no result set.

Note that procedures that call into Perl or PHP (LANGUAGE PERL, LANGUAGE PHP) external functions cannot return result sets. Procedures that call native functions loaded by the database server cannot return result sets.

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. For external calls, this clause establishes the ownership context for unqualified object references in the external environment.

When SQL SECURITY INVOKER is specified, more memory is used because annotation must be done for each user that calls the procedure. Also, when SQL SECURITY INVOKER is specified, name resolution is done as the invoker as well. Therefore, care should be taken to 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 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).

EXTERNAL NAME LANGUAGE ‘native-call’ native-call:[operating-system: ]function-name@library; ...

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

operating-system: UNIX—A procedure using the EXTERNAL NAME clause with no LANGUAGE attribute defines an interface to a native function written in a programming language such as C. The native function is loaded by the database server into its address space.

The library name can include the file extension, which is typically .dll on Windows and .so on UNIX. In the absence of the extension, the software appends the platform-specific default file extension for libraries. This is a formal example:

CREATE PROCEDURE mystring( IN instr LONG VARCHAR ) 
EXTERNAL NAME
'mystring@mylib.dll;Unix:mystring@mylib.so';

A simpler way to write the preceding EXTERNAL NAME clause, using platform-specific defaults:

CREATE PROCEDURE mystring( IN instr LONG VARCHAR )
EXTERNAL NAME 'mystring@mylib';

When called, the library containing the function is loaded into the address space of the database server. The native function executes as part of the server. In this case, if the function causes a fault, then the database server terminates. Because of this, loading and executing functions in an external environment using the LANGUAGE attribute is recommended. If a function causes a fault in an external environment, the database server continues to run.

For information about native library calls, see SQL Anywhere 11.0.1 > SQL Anywhere Server – Programming > SQL Anywhere Data Access APIs > SQL Anywhere External Function API > Calling external libraries from procedures.

EXTERNAL NAME LANGUAGE ‘c-call’ LANGUAGE { C_ESQL32 | C_ESQL64 | C_ODBC32 | C_ODBC64 } c-call:

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

operating-system: UNIX

To call a compiled native C function in an external environment instead of within the database server, the stored procedure or function is defined with the EXTERNAL NAME clause followed by the LANGUAGE attribute specifying one of C_ESQL32, C_ESQL64, C_ODBC32, or C_ODBC64.

When the LANGUAGE attribute is specified, then the library containing the function is loaded by an external process and the external function will execute as part of that external process. In this case, if the function causes a fault, then the database server will continue to run.

Sample procedure definition:

CREATE PROCEDURE ODBCinsert( 
IN ProductName CHAR(30),
IN ProductDescription CHAR(50)
)
NO RESULT SET
EXTERNAL NAME 'ODBCexternalInsert@extodbc.dll'
LANGUAGE C_ODBC32;

See SQL Anywhere 11.0.1 > SQL Anywhere Server – Programming > SQL Anywhere Data Access APIs > SQL Anywhere external environment support > The ESQL and ODBC external environments.

EXTERNAL NAME ‘clr-call’ LANGUAGE CLR clr-call : dll-name::function-name  ( param-type-1, ... )

operating-system: UNIX

To call a .NET function in an external environment, the procedure interface is defined with an EXTERNAL NAME clause followed by the LANGUAGE CLR attribute.

A CLR stored procedure or function behaves the same as a SQL stored procedure or function with the exception that the code for the procedure or function is written in a .NET language such as C# or Visual Basic, and the execution of the procedure or function takes place outside the database server (that is, within a separate .NET executable).

Sample procedure definition:

CREATE PROCEDURE clr_interface( 
IN p1 INT, 
IN p2 UNSIGNED SMALLINT, 
OUT p3 LONG VARCHAR)
NO RESULT SET
EXTERNAL NAME 'CLRlib.dll::CLRproc.Run( int, ushort, out string )' 
LANGUAGE CLR;

See SQL Anywhere 11.0.1 > SQL Anywhere Server – Programming > SQL Anywhere Data Access APIs > SQL Anywhere external environment support > The CLR external environment.

EXTERNAL NAME ‘perl-call’ LANGUAGE CLR perl-call:

 < file=perl-call > $sa_perl_return=perl-sub ($sa_perl_arg0, ... )

To call a Perl function in an external environment, the procedure interface is defined with an EXTERNAL NAME clause followed by the LANGUAGE PERL attribute.

A Perl stored procedure or function behaves the same as a SQL stored procedure or function with the exception that the code for the procedure or function is written in Perl and the execution of the procedure or function takes place outside the database server (that is, within a Perl executable instance).

Sample procedure definition:

CREATE PROCEDURE PerlWriteToConsole( IN str LONG VARCHAR) 
NO RESULT SET
EXTERNAL NAME '<file=PerlConsoleExample> 
WriteToServerConsole( $sa_perl_arg0 )' 
LANGUAGE PERL;

See SQL Anywhere 11.0.1 > SQL Anywhere Server – Programming > SQL Anywhere Data Access APIs > SQL Anywhere external environment support > The PERL external environment.

EXTERNAL NAME ‘perl-call’ LANGUAGE PHP  <file=php-file> print php-func($argv[1], ... )

To call a PHP function in an external environment, the procedure interface is defined with an EXTERNAL NAME clause followed by the LANGUAGE PHP attribute.

A PHP stored procedure or function behaves the same as a SQL stored procedure or function with the exception that the code for the procedure or function is written in PHP and the execution of the procedure or function takes place outside the database server (that is, within a PHP executable instance).

Sample procedure definition:

CREATE PROCEDURE PHPPopulateTable() 
NO RESULT SET
EXTERNAL NAME '<file=ServerSidePHPExample>
ServerSidePHPSub()'
LANGUAGE PHP;

See SQL Anywhere 11.0.1 > SQL Anywhere Server – Programming > SQL Anywhere Data Access APIs > SQL Anywhere external environment support > The PHP external environment.

EXTERNAL NAME java-call LANGUAGE JAVA ‘java-call‘ [   package-name. ] class-name.method-name ( method-signature

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

A Java method signature is a compact character representation of the types of the parameters and the type of the return value.

To call a Java method in an external environment, the procedure interface is defined with an EXTERNAL NAME clause followed by the LANGUAGE JAVA attribute.

A Java-interfacing stored procedure or function behaves the same as a SQL stored procedure or function with the exception that the code for the procedure or function is written in Java and the execution of the procedure or function takes place outside the database server (that is, within a Java Virtual Machine).

Sample procedure definition:

CREATE PROCEDURE HelloDemo( IN
name LONG VARCHAR ) 
NO RESULT SET
EXTERNAL NAME 'Hello.main([Ljava/lang/String;)V'
LANGUAGE JAVA;

See SQL Anywhere 11.0.1 > SQL Anywhere Server – Programming > SQL Anywhere Data Access APIs > SQL Anywhere external environment support > The Java external environment.

For example:

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

has this signature:

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

Standards

Permissions

Must have RESOURCE authority, unless creating a temporary procedure. For external procedures or to create a procedure for another user, must have DBA authority.