ESQL overview

Extended Structured Query Language (ESQL) is a programming language defined by WebSphere Message Broker to define and manipulate data within a message flow.

This section contains introductory information about ESQL.
Read the following information before you proceed:

ESQL is based on Structured Query Language (SQL) which is in common usage with relational databases such as DB2. ESQL extends the constructs of the SQL language to provide support for you to work with message and database content to define the behavior of nodes in a message flow.

The ESQL code that you create to customize nodes within a message flow is defined in an ESQL file, typically named <message_flow_name>.esql,, which is associated with the message flow project. You can use ESQL in the following built-in nodes:

You can also use ESQL to create functions and procedures that you can use in the following built-in nodes:

To use ESQL correctly and efficiently in your message flows, you must also understand the following concepts:

Use the ESQL debugger, which is part of the flow debugger, to debug the code that you write. The debugger steps through ESQL code statement by statement, so that you can view and check the results of every line of code that is executed.
Note: In previous releases there were several types of debugger, each of which handled a specific type of code, such as ESQL, message flows, or Java. In Version 6, these separate debuggers are integrated into a single debugger, which is known simply as "the debugger", and which handles all types of code.
Related concepts
Message flows overview
The message tree
Message flows, ESQL, and mappings
Message mappings overview
ESQL nodes and debugging
Related tasks
Developing message flows
Developing message mappings
Writing ESQL
Debugging ESQL
Related reference
Built-in nodes
ESQL reference