CICS VSAM Transparency for z/OS, Version 1.2


Functional overview

CICS® VT works by intercepting runtime calls to VSAM files from your application programs.

For batch programs, this interception is performed using an MVS™ subsystem. In CICS, the interception is handled by a global user exit (GLUE). The call interception is referred to as the " CICS VT runtime component".

At run time, CICS VT uses two driver modules for each migrated VSAM data set:

Table 1. Driver modules
Driver module Description
Data set Information Module (DIM) This defines the relationship between the VSAM record structure and the DB2® table it relates to.
Data set Driver Module (DDM) This contains the necessary SQL to access the DB2 table.

These modules are generated by standard CICS VT ISPF dialog functions. These functions are part of the " CICS VT mapping component".

There is a third component of CICS VT called the " CICS VT data migration component". This component deals with all aspects of the initial conversion of your VSAM files to DB2 tables.

The overall architecture of CICS VT can be viewed as these three separate components, which are discussed in more detail throughout the remainder of this section.





Last updated: December 6, 2013 20:43:10

Information Information

Feedback


Timestamp icon Last updated: Friday, 6 December 2013


http://pic.dhe.ibm.com/infocenter/cicsts/v5r1/topic///topics/cvtug_functional_overview.html