F15 Philip K. Gunning, DGI Anaheim, CA Sept , 2002 Fundamentals of DB2 SQL Procedures

IBM Data Management Technical Conference Outline Background Installation and Preparation Setup Development Center (SPB, et al) Building SQL Procedures Case Study Performance Considerations Summary

IBM Data Management Technical Conference Background

IBM Data Management Technical Conference Background First appeared in DB2 UDB V7.1 –DB2 for OS/390 V6.1 Other Database Vendors have had their own proprietary stored procedure languages for some time Search on YAHOO! found 78,000 hits on “Oracle Stored Procedures” Search on YAHOO! Found 31,600 hits on “Sybase Stored Procedures”

IBM Data Management Technical Conference Background Search on YAHOO! Found 25,200 hits on “DB2 Stored Procedures” Search on YAHOO! Found 44,500 hits on “Transact SQL” Search on YAHOO! Found 11 hits on “PL/SQL”

IBM Data Management Technical Conference Background Many applications have been written in their entirety in a stored procedure language –Flexibility –Enable Rapid Application Development –Minor learning curve since similar to SQL Portability Across Platforms –Cross Platform Development and Debugging

IBM Data Management Technical Conference Installation and Preparation

IBM Data Management Technical Conference Installation and Preparation UNIX –Application Development Client –AIX V4.3.3 ML9 or 5.1 ML1 –IBM C for AIX Version 5.0 –IBM Visual Age C++ Version 5.0 Windows XP,.NET, 2000, NT, ME, 98

IBM Data Management Technical Conference Installation and Preparation Change DBM CFG Parameter KEEPFENCED (KEEPDARI) to NO while developing and testing routines –If not, changes will not be reloaded as process that runs the routine will remain active db2 update dbm cfg using KEEPFENCED no

IBM Data Management Technical Conference Installation and Preparation UNIX –Set two registry values –DB2_SQLROUTINE_COMPILER_PATH –DB2_SQLROUTINE_COMPILE_COMMAND –PATH and LIBPATH environment variables set in db2profile and call to it is placed in.profile Can either use the db2set cmd or use the SQL Stored Procedure Builder Options dialog form the Development Center to set the values of these DB2 registry variables

IBM Data Management Technical Conference Installation and Preparation Windows –Application Development Client –SQL Procedures supported on NT, 2000, XP and.NET Server –DB2_SQLROUTINE_COMPILER_PATH –DB2_SQLROUTINE_COMPILE_COMMAND Need not be set if environment variables for compiler set as SYSTEM variables

IBM Data Management Technical Conference Installation and Preparation MVS Conformance Flagger –Used to Flag SQL for procedures developed on workstation which are being migrated to DB2 for OS/390 or Z/OS –ISO/ANSI SQL92 Entry Level Standard y/techarticle/0204milligan/0204milligan.ht mlhttp://www7b.boulder.ibm.com/dmdd/librar y/techarticle/0204milligan/0204milligan.ht ml

IBM Data Management Technical Conference Installation and Preparation Management Tools FMID required for DB2 for Z/OS or OS/390 –REXX Support for DSNTPSMP SP Creation –C compiler –Workload Manager and appropriate WLM application environments –DB2 V6.1 and above SQL Reference for Cross Platform Development

IBM Data Management Technical Conference Installation and Preparation Recoverable Resource Manager Services attachment facility (RRSAF) required on Z/OS

IBM Data Management Technical Conference SQL Procedure created via CREATE PROCEDURE COMMAND CREATE PROCEDURE update_salary ( IN employee_number CHAR(6), IN rating INT )

IBM Data Management Technical Conference Attendee Notes  Create procedure may fail in the precompile or compile stage. DB2 will create a log file that contains error messages. This log will be placed in the /sqlproc/db_name/schema_name/tmp or \sqlproc\db_name\schema_name\tmp directory on Windows.

IBM Data Management Technical Conference SQL SQL-Procedure Body keyword of CREATE PROCEDURE statement specifies the SQL statement that is the body of the SQL Procedure Multiple SQL Procedure statements can be specified within a compound statement

IBM Data Management Technical Conference SQL CREATE PROCEDURE bump_salary (IN deptnumber SMALLINT) LANGUAGE SQL BEGIN DECLARE SQLSTATE CHAR(5); DECLARE v_salary DOUBLE; DECLARE v_id SMALLINT; DECLARE v_years SMALLINT; DECLARE at_end INT DEFAULT 0; DECLARE not_found CONDITION FOR SQLSTATE '02000'; DECLARE C1 CURSOR FOR SELECT id, CAST(salary AS DOUBLE), years FROM staff WHERE dept = deptnumber; DECLARE CONTINUE HANDLER FOR not_found SET at_end = 1; Copyright IBM Corp. Sample Procedure

IBM Data Management Technical Conference SQL OPEN C1; FETCH C1 INTO v_id, v_salary, v_years; WHILE at_end = 0 DO CASE WHEN (v_salary < 2000 * v_years) THEN UPDATE staff SET salary = 2150 * v_years WHERE id = v_id; WHEN (v_salary < 5000 * v_years) THEN CASE WHEN (v_salary < 3000 * v_years) THEN UPDATE staff SET salary = 3000 * v_years WHERE id = v_id; ELSE UPDATE staff SET salary = v_salary * 1.10 WHERE id = v_id; END CASE; ELSE UPDATE staff SET job = 'PREZ' WHERE id = v_id; END CASE; FETCH C1 INTO v_id, v_salary, v_years; END WHILE; CLOSE C1; Copyright IBM Corp. Sample Procedure

IBM Data Management Technical Conference Attendee Notes  The procedure body consists of a procedure-name, that names the procedure being defined. In dynamic SQL, CURRENT SCHEMA is used as a qualifier for an unqualified name and the QUALIFIER bind option for static SQL. The unqualified name with the number of parameters is unique within its schema, but does not need to be unique across schemas. This is know as overloading in other languages. IN, OUT, or INOUT identifies the parameters of the procedure and specifies the mode, name and data type of each parameter.  Specific-name is used for commenting on or dropping the procedure. It can never be used to invoke the procedure.  Dynamic results is an upper bound for returned result sets.  Contains, Reads, and Modifies SQL DATA  LANGUAGE SQL FOR SQL PROCEDURES  SQL PROCEDURE BODY specifies the SQL statement that is the body of the SQL procedure.

IBM Data Management Technical Conference SQL CALL statement invokes stored procedure –Has a procedure signature which is a combination of schema, procedure name and number of parameters Returning Result Sets –Declare cursor on result set, open result set, and leave cursor open when exiting procedure –only unread rows are passed back –use nulls to improve performance

IBM Data Management Technical Conference SQL If result sets are required then RETURN to CALLER or RETURN TO CLIENT must be specified –RETURN TO CALLER results are only visible to program at previous nesting level –RETURN TO CLIENT results are visible only if procedure was invoked from a set of nested procedures, function or method invalidates this –Only visible to client application that made the call

IBM Data Management Technical Conference SQL See Appendix N, DB2 UDB SQL Reference for complete list of SQL statements allowed in SQL routines See DB2 for Z/OS SQL Reference for that platform

IBM Data Management Technical Conference SQL Condition Handlers –Control passed to condition handler if a condition is raised and you have declared a handler for the respective condition –If no handler, DB2 passes control to next statement in procedure body SQLCODE and SQLSTATE will contain corresponding values if they were declared

IBM Data Management Technical Conference Attendee Notes  If a statement raises an SQLWARNING or NOTFOUND condition, DB2 passes control to the handler you declared. If a statement raises an SQLEXCEPTION condition control is passed to the handler for that specific condition.

IBM Data Management Technical Conference SQL SIGNAL and RESIGNAL Statements –can be used to explicitly raise a specific SQLSTATE CALL is now a compiled statement and can be run from a command line

IBM Data Management Technical Conference Development Tools

IBM Data Management Technical Conference Development Center

IBM Data Management Technical Conference Stored Procedure Builder

IBM Data Management Technical Conference SQL Procedure

IBM Data Management Technical Conference SQL Procedure

IBM Data Management Technical Conference SQL Procedure

IBM Data Management Technical Conference Deploy

IBM Data Management Technical Conference Deploy

IBM Data Management Technical Conference Case Study Texas Department of Public Safety Combined 8 legacy applications into 1 using all SQL Procedures Started out on DB2 UDB V7.1 –JAVA Stored Procedures –Got proficient with SPB and development on Windows Migrated to DB2 for OS/390 V6.1 Switched to SQL Procedures

IBM Data Management Technical Conference Case Study Developed concurrently on DB2 for Windows whilst connectivity to OS/390 was being established –TCP/IP –DDF –CICS –Workload Manager (WLM) –WLM Stored Procedures

IBM Data Management Technical Conference Case Study After DB2 V6.1 and OS/390 configured developed over 300 SQL Procedures Implemented Texas Crime Information Center application totally in SQL Procedures Credited flexibility and ease of development in streamlining the typical development timeline

IBM Data Management Technical Conference Case Study Used DB2 Management Clients package DB2 Control Center DB2 Stored Procedure Builder DB2 Visual Explain

IBM Data Management Technical Conference Case Study Still did good Logical and Physical Design Extensive use of Identity Columns Developed good indexes via DB2 Explain and SQL Reviews Attaining sub-second response Continue to add new features/functionality using SQL Procedures

IBM Data Management Technical Conference Case Study Lessons Learned –Want to be leading-edge but not necessarily bleeding-edge! –Lot’s of time spent getting TCP/IP, DB2 for OS/390 V6.1, DSNTSMP stored procedure working along with WLM –Ran into 32k limitation and had to use multiple stored procedures –Starting/Stopping/Purging WLM procedures took some time to develop

IBM Data Management Technical Conference References  SC , What’s New, V8.1  DB2 UDB SQL Reference, Volume 1 and 2  SC , DB2 UDB Application Building Guide: Building and Running Applications V8.1  SC , DB2 Application Development Guide: Programming Server Applications

IBM Data Management Technical Conference References  DB2 UDB Command Reference, V8.1  ata/udb/ad ata/udb/ad  ftp://ftp.software.ibm.com/ps/db2/info ftp://ftp.software.ibm.com/ps/db2/info  SC DB2 for Z/OS SQL Reference  SC DB2 for Z/OS Application Programming and SQL Guide

IBM Data Management Technical Conference References 90/spbhttp:// 90/spb

IBM Data Management Technical Conference References

F15 Thanks! Anaheim, CA Sept , 2002 Fundamentals of DB2 SQL Procedures