DBRC access to DBD information when IMS manages ACBs

To perform certain functions, DBRC needs to read the database definitions (DBDs) that are currently active in the IMS system.

When IMS manages ACBs, the DBDs that are currently active are stored in the IMS catalog that the IMS system is using. For DBRC to read active DBDs, you need to specify the IMS catalog name to DBRC, either by recording it in the CATALOG field in the RECON data set, or by specifying it in the DBRC command that requires the DBD information. The CATALOG field in the RECON data set determines the IMS catalog that DBRC uses by default, and the CATALOG field is set by using the INIT.RECON or CHANGE.RECON commands. If DBRC does not find the name of an IMS catalog when it requires DBD information, DBRC looks for a DBD library data set, which, if it exists, might not contain the DBDs that are in use by the IMS system.

If you need to override the default IMS catalog, you can specify a different catalog name in the CATALOG field of each command that requires DBD information to instruct DBRC where to read DBDs from. Before ACBs managed by IMS are enabled, DBRC reads from the DBDLIB by default, with the value for the CATALOG field set to NULL.

If you use DDL when ACBs managed by IMS are enabled, IMS does not propagate DDL-defined DBD changes to a DBDLIB and does not check to see whether the DBDs in a DBDLIB are the same as those in use by the IMS catalog. Consequently, if you use DDL to modify or define any databases, you must either ensure that the DBDLIB is kept in sync with the IMS catalog, or use only the DBDs in the IMS catalog for IMS utilities and processes.