Adding or deleting DEDB segments using online change

You can add or delete a DEDB segment by using the online change function.

Adding or deleting segment types or changing segment formats affects the structure of a DEDB and constitutes a Database Level change. The addition or deletion of segment types (including the DEDB Sequential Dependent Segment type) affects the hierarchical structure and the segment prefix layout to implement this structure. Similarly, the change of individual segment formats changes the structure of the entire database and space allocations within each AREA of the DEDB.

To make structural changes to an existing DEDB, execute the procedural steps described below.

Procedure

  1. Use a specific customer-developed application program or OEM utility to unload the DEDB through existing system definitions.
  2. DBDGEN, PSBGEN and ACBGEN to generate the application control blocks to implement the DEDB structural changes. The changed or new application control blocks must be built into the active IMS system staging copy of ACBLIB, which is offline.
  3. Run the Online Change Copy utility (DFSUOCU0) to move the changed ACBLIB from the staging ACBLIB to the inactive (A or B) copy of the ACBLIB that is online to the active IMS system.
  4. Enter the normal /DBR command sequence to remove access to the DEDB from the active IMS system. This command may be issued any time prior to the /MODIFY COMMIT.
  5. Enter and follow the online change command sequence for PREPARE processing for ACBLIB changes.
  6. Enter and follow the online change command sequence for COMMIT/ABORT processing for ACBLIB changes.
  7. Delete, define and initialize all of the AREA data sets belonging to the DEDB with the new system definitions.
  8. Enter the normal /START DATABASE and /START AREA commands to make the DEDB and its areas accessible to the active IMS system.
  9. Use a specific customer-developed application program or OEM utility to reload the DEDB through the changed system definitions for the DEDB.