Converting to the Segment Edit/Compression exit routine

You might need to make changes to your database before you can use a Segment Edit/Compression exit routine, such as the IMS sample exit routine DFSCMPX0.

To convert an existing database to support a Segment Edit/Compression exit routine, follow these steps:

Procedure

  1. Determine whether the change you are making affects the code in any application programs. If the code is affected, make sure it gets changed.
  2. Unload your database, using the existing DBD and the HD Unload utility.
  3. Code a new DBD. The new DBD must specify the name of your edit routine for the segment types you need edited.
  4. If the change you are making affected the code in application programs, make any necessary changes to the PSBs for those application programs. If you have the DB/DC Data Dictionary, it can help you determine which application programs and PCBs are affected by the DBD changes you have made.
  5. Rebuild the ACB if you have ACBs prebuilt rather than built dynamically.
  6. Recalculate database space. You need to do this because the change you are making results in different requirements for database space.
  7. Delete the old database space and define new database space. If you are using VSAM, use the Access Method Services DEFINE CLUSTER command to define VSAM data sets.
  8. Reload the database, using the new DBD. Remember to make an image copy of your database as soon as it is reloaded.
  9. If your database uses logical relationships or secondary indexes, you must run reorganization utilities before and after reloading to resolve prefix information.