Refer to Datacom Datadictionary.
Here is an extract:
is a tightly coupled
application facility. It manages and stores database structure definitions including predefined entities (or record types) and corresponding relationships. Interconnected by standard and internal relationships, the standard entities form the model for the database environment. This model assures that the format of the data stored in the database matches the expectations of a program.
As part of the Datacom/AD installation, the
system and sample databases defined in the
. Each structured database is promoted from a TEST to PRODuction status and then cataloged from the
to the CXX.
During the post-installation for many of the products that use
is fully populated with the definitions required by the product. Therefore, you are not required to use any of the
online or batch facilities to customize it.
CA 7 jobs AL2DCA20, AL2DCA30 and AL2DCA40 that run DDUPDATE modify Datadictionary.
DDRTVCAT, executed in AL2DCA30, catalogs the CA 7 data base structure found in Datadictionary to the CXX.
The CXX contains the definition of the CA 7 data base in compressed format . Datacom cannot function without a valid CXX.
DDTRSLM updates both Datadictionary and the CXX when importing CA 7 table structures.
DDTRSLM runs in AL2DCA40 and AL2DCA70.
Backup of the CXX and Datadictionary should be run after the initial CA 7 installation and before/after running the HOLD ACTION of any CA 7 PTF for which a rerun of a CA 7 installation job is required. This is what CA 7 recommends to do. See Data Dictionary Backup