Writing an external procedure to access IMS databases

ODBA support uses RRS for syncpoint control of Db2 and IMS resources. Therefore, stored procedures that use ODBA can run only in WLM-established stored procedures address spaces.

When you write a stored procedure that uses ODBA, follow the rules for writing an IMS application program that issues DL/I calls.

IMS work that is performed in a stored procedure is in the same commit scope as the stored procedure. As with any other stored procedure, the calling application commits work.

A stored procedure that uses ODBA must issue a DPSB PREP call to deallocate a PSB when all IMS work under that PSB is complete. The PREP keyword tells IMS to move inflight work to an indoubt state. When work is in the indoubt state, IMS does not require activation of syncpoint processing when the DPSB call is executed. IMS commits or backs out the work as part of RRS two-phase commit when the stored procedure caller executes COMMIT or ROLLBACK.

A sample COBOL stored procedure and client program demonstrate accessing IMS data using the ODBA interface. The stored procedure source code is in member DSN8EC1 and is prepared by job DSNTEJ61. The calling program source code is in member DSN8EC1 and is prepared and executed by job DSNTEJ62. All code is in data set DSN1210.SDSNSAMP.

The startup procedure for a stored procedures address space in which stored procedures that use ODBA run must include a DFSRESLB DD statement and an extra data set in the STEPLIB concatenation.