DB2 SQL PL

Clara Liu, Fraser McAuthur, Michael Gao, Paul Yip, and Raul Chong are consultants from the Information Management Services at the IBM Toronto Laboratory. They work closely with the IBM DB2 development team and have extensive hands-on experience with the DB2 SQL Procedural Language (SQL PL) through their work with IBM business partners and customers. Drew Bradstock is the Product Manager for DB2 for Linux, UNIX and Windows. He works with all of DB2’s customers, users, developers and champions to ensure that each release exceeds customers’ expectations. Drew has been a speaker at numerous conferences, a Redbook author and is always looking for feedback on DB2. Zamil Janmohamed is a Websphere Commerce development manager at the IBM Toronto Lab. He manages a team focused on developer productivity and tooling for Websphere Commerce practitioners. He also has an extensive background working with relational databases, not only as it relates to developing applications, but also designing, implementing, and supporting databases.

1. Introduction.

    Installing DB2.

    History of Stored Procedures.

    A Brief Introduction to Stored Procedures, Triggers, and Functions.

    What's New in the Second Edition.

      DB2's SQL Procedural Language (SQL PL).

      Other Stored Procedure Languages.

      SQL PL Development Tools-DB2 Development Center.

    Book Conventions.

      Syntax Description.

      Meanings of Style.

      Book Structure.

      Contacting the Authors.

2. Basic SQL Procedure Structure.

    The CREATE PROCEDURE Statement.

      Procedure Name.

      Parameters.

      Specific Name.

      DYNAMIC RESULT SETS.

      CONTAINS SQL, READS SQL DATA, MODIFIES SQL DATA.

      DETERMINISTIC or NOT DETERMINISTIC.

      CALLED ON NULL INPUT.

      INHERIT SPECIAL REGISTERS.

      OLD SAVEPOINT LEVEL, NEW SAVEPOINT LEVEL.

      LANGUAGE SQL.

      EXTERNAL ACTION or NO EXTERNAL ACTION.

      PARAMETER CCSID.

      SQL Procedure Body.

    The SQL Procedure Body Structure.

      Comments.

      Variables.

      Setting Variables.

      DB2 Special Registers.

    Bringing It All Together Example.

    DB2 UDB for iSeries Considerations.

      FENCED and NOT FENCED.

      COMMIT ON RETURN.

      SET OPTION Statement.

    DB2 UDB for zSeries Considerations.

      FENCED.

      NO DBINFO.

      NO COLLID or Collid collection-id.

      WLM ENVIRONMENT.

      ASUTIME.

      STAY RESIDENT.

      PROGRAM TYPE.

      SECURITY.

      RUN OPTIONS.

      COMMIT ON RETURN.

      STOP AFTER SYSTEM DEFAULT FAILURES or CONTINUE AFTER FAILURE.

    Summary.

3. Overview of SQL PL Language Elements.

    DB2 Data Types.

      Valid DB2 Built-In Data Types and Their Value Ranges.

    Large Objects.

    Choosing Proper Data Types.

    Working with User-Defined Distinct Types.

    Data Manipulation.

      Working with Dates and Times.

      Working with Strings.

    Working with Generated Columns.

    Working with Identity Columns and Sequence Objects.

      Identity Column.

      Sequence Object.

    Platform Portability Considerations.

    Summary.

4. Using Flow of Control Statements.

    Compound Statements.

      NOT ATOMIC Compound Statement.

      ATOMIC Compound Statement.

      Using Labels.

    Conditional Statements.

      The IF Statement.

      The CASE Statement.

    Looping Statements.

       FOR Loop.

      WHILE Loop.

      REPEAT Loop.

      LOOP.

    Transfer of Control Statements.

      GOTO.

      LEAVE.

      ITERATE.

      RETURN.

      COMMIT.

      ROLLBACK.

    Summary.

5. Understanding and Using Cursors and Result Sets.

    Using Cursors in SQL Procedures.

    Positioned Delete.

    Positioned Update.

    Selecting Data from UPDATE, INSERT, or DELETE Statements.

    Cursor Behavior with COMMIT/ROLLBACK.

      Save Points Within Procedures.

    Using Cursors to Return Result Sets.

    Returning Multiple Result Sets.

    Cursors and Locking.

      Lock Modes.

      Isolation Levels.

      Controlling Locking in DB2 LUW.

      Controlling Locking in DB2 UDB for iSeries.

      Controlling Locking in DB2 UDB for zSeries.

    DB2 UDB for iSeries Considerations.

      DECLARE CURSOR Statement in DB2 UDB for iSeries.

    Summary.

6. Condition Handling.

    Basic Error Checking: SQLCODE and SQLSTATE.

    Condition Handlers.

    Custom Errors and Error Messages.

      Using SIGNAL to Force the Invocation of a Handler.

      Using RESIGNAL to Force the Invocation of a Handler.

      Scope of Handlers.

      RAISE_ERROR Function.

      GET DIAGNOSTICS.

    Processing Results from Called Procedures.

    Bringing It All Together.

    DB2 UDB for iSeries Considerations.

      SIGNAL and RESIGNAL Statements.

      RAISE_ERROR function.

      GET DIAGNOSTICS.

    DB2 UDB for zSeries Considerations.

      Condition Handlers.

      GET DIAGNOSTICS Statement.

      RETURN Statement.

    Summary.

7. Working with Dynamic SQL.

    PREPARE and EXECUTE: The Two Phases of Any SQL Statement.

    Dynamic SQL Versus Static SQL.

    Restrictions and Considerations.

    Using Dynamic SQL with EXECUTE IMMEDIATE.

    Escaping Single Quotes (').

    Reusing Dynamic SQL Statements with PREPARE and EXECUTE.

    Using Dynamic SQL in Cursors.

    Dynamic CALL Statements.

    Authorization Consideration.

    Summary.

8. Nested SQL Procedures.

    Basic Nested SQL Procedures.

    Passing Parameters Between Nested SQL Procedures.

    Returning Values from Nested SQL Procedures.

    Returning Result Sets from Nested SQL Procedures.

      Returning Result Sets to the Client.

      Returning Result Sets to the Caller.

      Receiving Result Sets as a Caller.

      Receiving Multiple Result Sets as a Caller.

    Receiving Results from a Procedure in a Trigger.

    Levels of Nesting.

      Recursion.

    Security.

    Summary.

9. User-Defined Functions and Triggers.

    The CREATE FUNCTION Statement.

      Function Name and Parameters.

      Returns Function Output.

      Specific Name.

      Language SQL.

      DETERMINISTIC or NOT DETERMINISTIC.

      EXTERNAL ACTION or NO EXTERNAL ACTION.

      CONTAINS SQL, READS SQL DATA, MODIFIES SQL DATA.

      STATIC DISPATCH.

      CALLED ON NULL INPUT.

      INHERIT SPECIAL REGISTERS (LUW and iSeries Only).

      PREDICATES (LUW only).

      SQL Function Body.

    User-Defined Functions by Examples.

      A Simple Scalar UDF Example.

      A Complex Scalar UDF Example.

      A Table UDF Example (LUW and iSeries).

      Invoking SQL Procedures in UDFs (LUW and iSeries Only).

    The CREATE TRIGGER Statement.

      Trigger Name.

      BEFORE, AFTER, or INSTEAD OF.

      INSERT, DELETE, or UPDATE.

      REFERENCING Clauses.

      FOR EACH ROW or FOR EACH STATEMENT.

      MODE DB2SQL.

      Triggered Action.

    Triggers by Examples.

      A BEFORE Trigger Example.

      An AFTER Trigger Example.

      A Complex AFTER Trigger Example.

      An INSTEAD OF Trigger Example (for LUW Only).

      A Comparison of View Triggers and Table Triggers (LUW only).

      Invoking UDFs and SQL Procedures from Triggers.

    Considerations for Invoking SQL Procedures from UDFs and Triggers.

      Data Access Restrictions.

      Transaction Control in SQL Procedures.

      Table Read or Write Conflict in SQL Procedures on LUW.

    DB2 for iSeries Considerations.

    DB2 for zSeries Considerations.

      The CREATE FUNCTION Statement.

      Trigger Considerations.

       Invoking UDFs and SQL Procedures from Triggers.

      Nesting SQL Statements.

    Summary.

10. Leveraging DB2 Application Development Features.

    Leveraging Advanced SQL.

      Combining SELECT with INSERT, UPDATE, and DELETE.

    Declared Global Temporary Tables.

      Introduction to Temporary Tables.

      Creating the Environment for Temporary Tables.

      Declaring Global Temporary Tables.

      Using Temporary Tables in SQL Procedures.

      Sharing Temporary Tables Between Multiple Procedures.

      Considerations.

      Created Global Temporary Tables.

    Working with Save Points.

      Introduction to Application Save Points.

      Using Save Points in SQL Procedures.

    Sequence Objects.

    Summary.

11. Deploying SQL Procedures, Functions, and Triggers.

    Deploying on Linux, UNIX, and Windows.

      Deploying SQL Procedures Using DDL.

      Deploying Functions.

      Deploying Triggers.

      Deploying Using GET ROUTINE and PUT ROUTINE.

      Deploying Using Older Releases of DB2.

       Code Page Considerations.

      Backup and Recovery Considerations.

    Deployment Considerations for DB2 for zSeries.

      Deploying SQL Procedures.

      Deploying Functions and Triggers.

      Deployment Considerations Based on Your C Compiler Requirements.

    Common Deployment Considerations for LUW and zSeries.

      Deploying from One Database to Another.

    Deploying in DB2 UDB for iSeries.

Using the Development Center.

Using iSeries Navigator and CL Commands in iSeries.

    Summary.

12. Performance Tuning.

    Performance Considerations for LUW.

      The Configuration Advisor.

      Monitoring SQL Performance.

      Using Explain to Analyze Access Plans.

      The Design Advisor.

      Large Object (LOB) Considerations.

      Temporary Tables Considerations.

      Ongoing Maintenance to Keep Performance at Its Peak.

    DB2 for iSeries Considerations.

      Monitoring Memory Usage.

      Performance Monitors and Commands.

      Query Optimizer and Access Plans.

      Variable Length Columns and Large Objects.

      Database Statistics.

    DB2 for zSeries Considerations.

      The EDM Statement Cache.

      The Performance Expert Tool.

      Improving Response Time and Throughput.

      Tuning Your Queries.

      Limit Resources for a Stored Procedure.

      Considerations for Stored Procedures in a Distributed Environment.

    Summary.

13. Best Practices.

    Table and Index Best Practices.

      Table Considerations.

      Temporary Table Considerations.

      Index Considerations.

    Best Practices for Easier Code Maintenance.

      Code Readability.

      Code Size.

      Grouping SQL Procedures by Schema.

      Naming Conventions.

      Return Values Versus Out Parameters.

      Exception Handling.

      Commit and Rollback.

    Best Practices for Performance.

      Exceptions.

      Repetitive SQL.

      Table Truncation.

      Reducing Locking.

      Dynamic SQL for DDL.

      Using a Single Insert to Replace Multiple Insert Statements.

      Value Assignment.

      Deterministic Versus Not Deterministic.

      Case Statement.

      Functions.

    Working with Result Sets.

      Cursor Considerations.

      Limiting Result Sets.

      Optimizing Result Set Returns.

      Minimize Result Set Columns.

    Precompile Options on iSeries.

    Summary.

Appendix A. Getting Started with DB2.

    Getting Started with DB2 UDB for LUW.

      Launching the DB2 Command Window.

      Launching the DB2 Command Line Processor.

      Overview of DB2 Architecture.

      DB2 Instances.

      Creating Databases.

      Executing SQL in the DB2 Command Window.

      Executing SQL in DB2 Interactive Mode.

      Configuring the DB2 Environment.

      Understanding Buffer Pools.

      Working with Table Spaces.

      Working with Tables.

    Getting Started with DB2 UDB for iSeries.

      Launching the Interface.

      Overview of the DB2 UDB for iSeries Architecture.

      Executing SQL in DB2 UDB for iSeries.

      Working with Tables.

      Catalog.

    Getting Started with DB2 UDB for zSeries.

      Overview of the BD2 UDB for zSeries Architecture.

      Catalog.

      Interacting with DB2 for zSeries.

    Summary.

Appendix B. Inline SQL PL for DB2 UDB for Linux, UNIX, and Windows.

    Dynamic Compound Statement.

    Stand-Alone Code.

    Choosing Between Dynamic Compound Statements and SQL Procedures.

    Summary.

Appendix C. Building from the Command Line.

    Configuring the Build Environment.

    Building SQL Procedures.

      Creating a DB2 Command-Line Processor Script.

    Building SQL Procedures in DB2 UDB for iSeries.

    Building SQL Procedures in DB2 for zSeries.

      The Build Process.

      Methods to Build a DB2 for zSeries SQL Procedure.

    Summary.

Appendix D. Using the DB2 Development Center.

    Installing the DB2 Development Center.

    DB2 for Windows.

    DB2 for Linux and UNIX.

    Using the Development Center for the First Time.

    Development Center Views.

    Customizing the Development Center.

    Running Procedures.

    Stored Procedure Run Settings.

    Debugging Stored Procedures.

    Debugging Nested Stored Procedures.

    Working with Projects.

    Importing Stored Procedures.

    DB2 for iSeries Considerations.

    DB2 for zSeries Considerations.

    Environment Settings.

    Developing SQL Stored Procedures from the Development Center.

    The Project and Server Views.

    Debugging DB2 for zSeries SQL Stored Procedures.

    Summary.

Appendix E. Security Considerations in SQL Procedures.

    Privileges.

      Privileges Required by Developers.

      Privileges Required by Users.

    Using Stored Procedures in a Production Environment.

    DB2 for zSeries Considerations.

      DYNAMICRULES Bind/Rebind Option Value.

      The Package's Runtime Environment.

    The DEFINE Behavior.

    The INVOKE Behavior.

    Common Attribute Values for the DEFINE, and INVOKE Behaviors.

    Simplifying Authorization.

    Summary.

Appendix F. DDL.

    Creating the SAMPLE Database on LUW.

    Creating the SAMPLE Database on iSeries.

    Creating the SAMPLE Database on zSeries.

    SAMPLE Database.

    DDL for Additional Database Objects: Script #2 sampleDDL_2.db2.

Appendix G. Additional Resources.

    IBM Redbooks.

      LUW.

      ISeries.

      ZSeries.

      Cross-Platform.

    Certification.

      Certification Guides.

      Tutorials.

    Education.

      IBM Learning Services.

      IBM Solution Partnership Centers (SPCs).

      Tutorials.

    Books.

    Additional Websites.

      DB2 FixPaks and Downloads.

    Email Services and Periodicals.

    User Groups and Conferences.

Appendix H. Sample Application Code.

    Receiving Result Sets in Java.

      Receiving Result Sets in a Java Application.

      Receiving Result Sets in a Java Stored Procedure.

    Receiving Result Sets in a C or C++ Application.

    Receiving Multiple Result Sets in Java.

      Receiving Multiple Result Sets in a Java Application.

      Receiving Multiple Result Sets in a Java Stored Procedure.

    Receiving Multiple Result Sets in a C or C++ Application.

Index.