Database segment mapping enhancement

Starting with IMS V14, this enhancement to database segment mapping allows application developers to access an IMS database segment whose schema is determined by the key feedback data from a parent segment without knowledge of the database schema. It gives database administrators the ability to use the IMS Catalog to maintain field mappings that are dependent on the key feedback data of a segment, in the hierarchical path of the current segment, and make that mapping automatically available to consumers such as application developers and tooling. This enhancement is made available by the following APARs:/PTFs:

• IMS V14 PI96463/UI59325 and PH05093/UI61283
• IMS V15 PI97302/UI59327 and PH05433/UI61285
• V14 APAR PH03415 and V15 APAR PH03426 for IMS Universal Drivers (UDB)

The DSFMAP statement is being enhanced to support a new optional parameter called control segment name, CTLSEGNM. The control segment name parameter specifies the name of a segment in the same hierarchical path of the current segment. When CTLSEGNM is specified, the value on the DEPENDINGON parameter must be a field within the key range of the segment specified on CTLSEGNM. The control segment name will be saved in the IMS Catalog’s MAP segment and can be retrieved by the IMS Universal Drivers via a GUR call. The Universal Drivers can then use the control segment value to apply the appropriate mapping to the result set that will be returned to the application.

This APAR modifies the following items:

• The DFSMAP macro in DBDGEN allows specifying the optional parameter CTRLSEGNM.
• ACBGEN can process the optional parameter CTLSEGNM that can be specified on the DFSMAP macro.
• The IMS Catalog populate utility stores the CTLSEGNM value in the MAP segment of the IMS Catalog.
• The GUR DL/I returns the CTLSEGNM value in the MAP segment of the IMS Catalog.
• The DBD XML schema for the GUR DL/I call includes the CTLSEGNM value.

Requirements

To include the new mapping information in the DBD, use the optional control segment name parameter, CTLSEGNM= in the DFSMAP macro in conjunction with the DEPENDINGON= parameter. Ensure that the control segment is in the same hierarchical path as the segment you are trying to map and the field you specify on the DEPENDINGON= parameter must be part of the key of the control segment. After the CTLSEGNM is added to the DFSMAP statement you must perform DBDGEN and ACBGEN for the affected resources as well as run the Catalog Populate Utility for IMS to write the CTLSEGNM to the IMS Catalog in the MAP segment.

Changes to utilities

IMS Catalog Populate Utility has been updated to store the CTLSEGNM value in the MAP segment of the IMS Catalog.

Documentation changes

The following table lists the publications that contain new or changed topics for the Database segment mapping enhancement. Publications that are not impacted by this enhancement are not included in the table.