Initialize (DIB)

Purpose
The Initialize dialog generates JCL that runs the Initialize (DIB) function. The Initialize function initializes databases.
Usage notes
The Batch database initialization JCL created by FM/IMS has the following flows:
Figure 1. Flows for Initialize (DIB) step

This diagram shows the inputs to and outputs from the Initialize (DIB) function. The inputs are FMN1JIN, FMNIMSIN, and IMS database data sets. The outputs are SYSPRINT, and the initialized database.

FM/IMS can initialize the IMS database data sets associated with an IMS database.

If you select Delete/Define IMS data sets on the Initialize Entry panel FM/IMS retrieves the data set information of the data sets listed on the Database Data Set Specification panel and builds JCL to delete or define these data sets.

The Initialize utility can be executed for these types of IMS databases:

Full function
  • HDAM, Hierarchical Direct Access Method
  • HIDAM, Hierarchical Index Direct Access Method
  • HISAM, Hierarchical Index Sequential Access Method
  • SHISAM, Simple Hierarchical Index Sequential Access Method
  • HSAM, Hierarchical Sequential Access Method
  • SHSAM, Simple Hierarchical Sequential Access Method

The Initialize process for a full function database depends on whether the database has secondary indexes, logical relationships or neither.

The simplest steps to initialize a full function database are:

  1. Database initialization, insert a dummy segment.
  2. Delete the dummy segment.

If the database has logical relationships the steps are:

  1. Delete work datasets.
  2. IMS Prereorganisation Utility (DFSURPR0)
  3. Database initialization, insert a dummy segment
  4. IMS Database Prefix Resolution Utility (DFSURG10)
  5. IMS Database Prefix Update Utility (DFSURGP0)
  6. Delete the dummy segment.
  7. Delete work datasets.

If the database has secondary indexes the steps are:

  1. 1. Delete work datasets.
  2. IMS Prereorganisation Utility (DFSURPR0)
  3. Database initialization, insert a dummy segment.
  4. IMS Database Prefix Resolution Utility (DFSURG10)
  5. HISAM Reorganization Unload Utility (DFSURUL0)
  6. HISAM Reorganisation Load Utility (DFSURRL0)
  7. Delete the dummy segment.
  8. Delete work datasets.
Fast Path
  • DEDB, Data Entry Database (Fast Path)

For a DEDB the IMS Utility DBFUMIN0 is used to initialize the areas.

HALDBs
  • PHDAM, Partitioned Hierarchical Direct Access Method (HALDB)
  • PHIDAM, Partitioned Hierarchical Index Direct Access Method (HALDB)

For a HALDB database the steps to initialize the database are:

  1. Delete Work data sets.
  2. Set the master HALDB database to PINIT (DSPURX00).
  3. Initialize the HALDB partitions: IMS Prereorganisation Utility (DFSURPR0)
  4. Generate IMS image copy (DSPURX00) only if "Submit image copy" has been selected. Please note that the HALDB partitions are not available until an image copy has been run.
  5. Delete Work data set.
FMNIMSIN
Contains the control statements for the Initialize. These control statements are discussed below.
IMS database data sets
In DLI mode, FM/IMS includes DDs for each of the IMS database data sets associated with the IMS database being printed. If the database has logical relationships, the data sets for the logically related databases need to be included.
SYSPRINT
This contains the FM/IMS messages that were issued by FM/IMS while extracting the IMS data, as well as the printed IMS segments.
FMN1JIN
Points to the FM/IMS skeleton library. This DD statement is only used when you are initializing HALDB databases.