Creating runtime database resource and descriptor definitions with the CREATE command

With dynamic resource definition (DRD) enabled, you can create runtime resources and resource descriptors dynamically, eliminating the need to use the online change process or the batch system definition process with an IMS cold start.

Create runtime database resource and descriptor definitions using the CREATE DB and CREATE DBDESC commands.

Procedure

  1. Optional: Issue a QUERY DBDESC DEFAULT(Y) SHOW (ALL) command to view the current database default settings and evaluate whether they meet your requirements for the new database resource or descriptor definition.
    If the default settings do not meet your requirements, you have the following options:
    • Override the default settings by issuing the CREATE command with parameter values that meet your requirements.
    • Create the resource or descriptor definition based on an existing resource or descriptor definition by using either the LIKE (RSC(resource_name)) keyword or the LIKE (DESC(descriptor_name)) keyword on the CREATE command.
    • Create a default descriptor by issuing a CREATE DBDESC NAME() SET (DEFAULT(Y)) command with the settings that meet your requirements.
    The next two steps can be performed in any order.
  2. Issue a CREATE DB or CREATE DBDESC command to create a database resource definition or database descriptor definition, respectively.
  3. Define the database, as well as its relationships to other resources, by running the Database Description Generation (DBDGEN) utility.

After dynamically defining a database resource, before it can be used, a database management block (DMB) must reside in the IMS.ACBLIB data set. If the database that was dynamically defined is a main storage database (MSDB):

  • The database segments must be in the MSDBINIT data set.
  • The MSDBs must be defined in the DBFMSDBx procedure.
  • The DBFMSDBx procedure must be in the IMS.PROCLIB data set.

For information about the CREATE command, see IMS Version 15.5 Commands, Volume 1: IMS Commands A-M.

For information about loading MSDB segments into the MSDBINIT data set, see MSDB Maintenance utility (DBFDBMA0).

For information about the DBFMSDBx procedure, see DBFMSDBx member of the IMS PROCLIB data set.

For general information about MSDBs, see IMS Version 15.5 Database Administration.