Download DB2 Stored Procedure Introduction Unit objectives

DB2 STORED PROCEDURE
INTRODUCTION
UNIT OBJECTIVES
After completing this unit, you should be able to:
 Describe a stored procedure
 Determine when a stored procedure should be
used
 Describe execution flow using stored procedures
 List DB2 stored procedure design and general
tips
WHAT IS A STORED PROCEDURE?
A Stored Procedure:
 Is an executable program under control of the
DB2 server
 Is invoked via the SQL CALL statement
 May contain business logic
 May be invoked locally or remotely
 May receive or pass parameters
 May produce result sets
WHEN TO USE A STORED PROCEDURE
Stored procedures may be justified when:
 The application's performance expectations are
not being met
 There are a large number of clients to which
application code is distributed.
 The client application generates relatively heavy
database activity, but involves little user
interaction.
 The client application code changes frequently.
 The access to the client application code needs to
be controlled.
 The client application executes many SQL
statements.
CONSIDERATIONS WHEN USING STORED
PROCEDURES
Stored procedures are incorporated by:
 Determining client portion of application
 Thin client?
 Selecting stored procedure server
 Developing stored procedure
 Determining calling parameters
 Selecting programming language / SQL PL, PL
SQL / IBM DB2 Data Studio Developer / CLP,
Command Editor, Text Editor
 Defining SP to server
 Coding and testing
APPLICATION FLOW
CLIENTCLIENT/SERVER: THE BIG
PICTURE
SERVER PROCEDURE: DESIGN/GENERAL
TIPS
Consider the cost of invoking a stored procedure
versus the cost of network transmission for a
distributed application.
 Stored procedures run in background.–Do not use
the standard I/O streams
 No commands to terminate current process.
 Overloading stored procedures restricted to
parameter subsets.
 SQL limited by stored procedure CREATE
parameters.

UNIT SUMMARY
Describe a stored procedure
 Determine when a stored procedure should be
used
 Describe execution flow using stored procedures
 List DB2 stored procedure design and general
tips
