Converting databases to DEDB

Converting a database to DEDB can be performed in a few steps; however, you need to perform a number of preliminary steps also.

If your database requires logical relationships, a secondary index, or fixed-length segments, DEDBs cannot be used.

You need to do the following before changing your database to DEDBs:

  • Determine whether or not your application programs can tolerate the FH (data unavailable) status code.
  • Determine whether or not your database can tolerate a randomizing routine (might not be a problem when changing from HDAM).
  • Recalculate database space, particularly when using DEDB features such as partitioning and data set replication.
  • Determine which pointers are available to use.

To change to DEDBs:

Procedure

  1. Unload your database using the existing DBD and one of the following:
    • Your unload program
    • The HD Reorganization Unload utility if database records are in physical root key sequence
  2. Code a new DBD for the DEDBs.
  3. Execute the DBD generation.
  4. For non-VSAM data sets, delete the old database space and define the new database space. For VSAM data sets, delete the space allocated for the old clusters and define space for the new clusters.
  5. Run the DEDB initialization utility (DBFUMIN0).
  6. Run the user DEDB load program.