Adding new fields to a segment of an active DEDB area with the DEDB Alter utility

You can add one or more fields to existing free space that is in a segment of an active DEDB area while the DEDB area remains accessible online. With the ALTERDB function of the DEDB Alter utility (DBFUDA00), you also can replace the DEDB randomizer for the DEDB database to be altered and add a Segment Edit/Compression exit routine for a segment.

The DEDB Alter utility's ALTERDB function supports DEDB databases with and without sequential dependent (SDEP) segments defined.

Procedure

  1. Prepare for adding new fields to an active DEDB area online:
    1. If you are replacing the randomizer or adding a Segment Edit/Compression exit routine, assemble and link edit the randomizer and the Segment Edit/Compression exit routine into the IMS SDFSRESL or one of the libraries of the IMS SDFSRESL STEPLIB concatenation.

      If you are using the DEDB Alter utility to add a Segment Edit/Compression exit routine, the Segment Edit/Compression exit routine must be able to handle mixed compressed and non-compressed data in a DEDB database. If data is non-compressed, on read access, it does not expand the non-compressed data, and on write access, it compresses the data and writes out as compressed data. If data is compressed, on read access, it expands the compressed data, and on write access, it compresses the data and writes out as compressed data.

    2. Add one or more fields to existing free space that is in a segment of an active DEDB area.
      • If you use the DBDGEN utility, add one or more FIELD statements under the SEGM statement of the segment that you are altering.
      • If you use DDL, use the ALTER TABLE statement with the INTERNALNAME parameter.
    3. If you are replacing the randomizer, change the RMNAME parameter in the DEDB DBD definitions.
      • If you use the DBDGEN utility, change the RMNAME parameter on the DBD statement.
      • If you use DDL, change the RMNAME parameter on the ALTER DATABASE statement.
    4. If you are adding a Segment Edit/Compression exit routine, perform one of the following options:
      • If you use the DBDGEN utility, add the COMPRTN parameter on a SEGM statement.
      • If you use DDL, add the EDITPROC parameter on the ALTER TABLE statement.
    5. If you use the IMS generation utilities, run the DBDGEN utility with the FIELD statements that you added to alter the new DEDB DBD definitions for the active DEDB area.
    6. If you use the IMS generation utilities, run the ACBGEN utility for all PSBs that reference the changed DEDB DBD definitions to the staging ACBLIB.
      If you are using the IMS catalog, use one of the following methods to update it after the DEDB Alter utility finishes:
      • Run both the ACB Maintenance utility and the IMS Catalog Populate utility (DFS3PU00).
      • Run the IMS catalog ACBGEN utility (DFS3UACB), which builds the ACBs and populates the IMS catalog in a single job step.
    7. If ACBMGMT=CATALOG is specified in the DFSDFxxx member of the IMS PROCLIB data set, populate the new DEDB DBD definitions to the IMS catalog by using one of the following methods:
      • By using the staging ACBLIB that you created in step 4 as input, run the IMS Catalog Populate utility (DFS3PU00) and use the MANAGEDACBS statement with the STAGE parameter.
      • Use DDL.
  2. Run the DEDB Alter utility by using the ALTERDB function to alter an active DEDB area while the DEDB area remains accessible online.

    If you are adding a Segment Edit/Compression exit routine, during DEDB Alter utility execution the new Segment Edit/Compression exit is not invoked for any areas. The Segment Edit/Compression exit routine is not enabled during DEDB Alter processing. Instead, it is enabled for all DEDB areas after successful DEDB Alter utility completion.