WebSphere Message Brokers
File: ak05800_
Writer: Bill Oppenheimer

Task topic

This build: July 31, 2007 21:32:31

Accessing databases from ESQL

ESQL has a number of statements and functions for accessing databases:
You can access user databases from Compute, Database, and Filter nodes.
Note: There is no difference between the database access capabilities of these nodes; their names are partly historical and partly based on typical usage.
You can use the data in the databases to update or create messages; or use the data in the message to update or create data in the databases.
Note that:
  • Any node that uses any of the ESQL database statements or functions must have its Data Source property set with the name (that is, the ODBC DSN) of a database. The database must be accessible, operational, and allow the broker to connect to it.
  • All databases accessed from the same node must have the same OBDC functionality as the database specified on the node’s Data Source property. This requirement is always satisfied if the databases are of the same type (for example, DB2 or Oracle), at the same level (for example, release 8.1 CSD3), and on the same platform. Other database combinations may or may not have the same OBDC functionality. If a node tries to access a database that does not have the same OBDC functionality as the database specified on the node’s Data Source property, the broker issues an error message.
  • All tables referred to in a single SELECT FROM clause must be in the same database.

You must ensure that suitable ODBC data sources have been created on the system on which the broker is running. If you have used the mqsisetdbparms command to set a user ID and password for a particular database, the broker uses these values to connect to the database. If you have not set a user ID and password, the broker uses the default database user ID and password that you supplied on the mqsicreatebroker command (as modified by any subsequent mqsichangebroker commands).

z/OS platform On z/OS systems, use the JCL member BIPSDBP in the customization data set <hlq>.SBIPPROC to perform the mqsisetdbparms command.

You must also ensure that the database user IDs have sufficient privileges to perform the operations your flow requires. Otherwise errors will occur at runtime.

Select the Throw exception on database error property check box and the Treat warnings as errors property check box, and set the Transaction property to Automatic, to provide maximum flexibility. You can then use the COMMIT and ROLLBACK statements for transaction control, and create handlers for dealing with errors.

Related concepts
Message flows overview
ESQL overview
Message modeling
Related tasks
Designing a message flow
Defining message flow content
Configuring globally coordinated message flows
Accessing databases from message flows
Managing ESQL files
Related reference
mqsichangebroker command
mqsicreatebroker command
mqsisetdbparms command
Compute node
Database node
Filter node
ESQL reference
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This build: July 31, 2007 21:32:31

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