Defining, Generating, and Punching a DMCL › Adding Segments to the DMCL › Required Segments

Required Segments

Segments Required for Central Version

The DMCL used under the central version must contain physical descriptions of all segments to be accessed under the central version. The segments include those defining:

• The system dictionary
• The user catalog
• Additional system areas required for central version operations:
  • DDLDCLOG
  • DDLDCRUN
  • DDLDCSCR
  • SYSMSG.DDLDCMSG
• One or more application dictionaries
• One or more user databases

The user catalog may not be required depending on your security implementation.

Note: For more information, see the CA IDMS Security Administration Guide.

Each central version must have its own DDLDCLOG system area and if used, its own DDLDCSCR area. In a non-data sharing environment, each central version must also have its own DDLDCRUN system area. In a non data-sharing environment, only one central version can update an area at a time. In a data-sharing environment, all areas except DDLDCLOG and DDLDCSCR can be shared and updated simultaneously by multiple central versions.

Segments Required for Local Mode

The DMCL used in local mode contains all segments to be accessed by the application. Generally these segments include:

• The system dictionary
• The user catalog
• The message area, SYSMSG.DDLDCMSG
• All user databases to be accessed by the application
• For applications using SQL:
  • A local mode scratch area, DDLOCSCR, or a system scratch area, DDLDCSCR, unless scratch in memory is in effect
  • The application dictionary containing the table definitions
• For applications using non-SQL DML:
  • The application dictionary containing the subschema load module

The system dictionary and user catalog may not be required, depending on how security is implemented in your environment.

Note: For more information, see the CA IDMS Security Administration Guide.

Subschema load modules can be loaded from a load library instead of a dictionary. A warning message may be written to the job log if the segment containing the load area (DDLDCLOD) for the default dictionary is not included in the DMCL.