The default DDM contains SQL to support all the possible calls you can make to a VSAM data set. In certain circumstances, you may want to restrict access to prevent data updates, and CICS® VT provides the ability to generate a read-only DDM facility for this purpose.
You request a read-only DDM in the manual mapping dialogs. Select the DIM and specify U to update the DIM mapping. This display the screen shown in Figure 1:
--------------------- CICS VT: Update data set mapping ------------------------ Command ===> ________________________________________________ Scroll ===> CSR_ DIM name :dim-name File information: VSAM filetype . ===> KSDS (KSDS,KSDV,RRDS,RRDV) Record length .. ===> 04096 (Maximum in bytes) Fill character . ===> __ ("FF","00",blank) CICS VT information: DB2 table: (Look-up available) Table creator ===> DBADM............................................... + Table name . . ===> DB2-table........................................... + Read Only DDM ===> module________ (Optional) Press: Enter=Update PF3=Exit
Specify the name of the read-only DDM you want to generate. You can specify any valid name.
The DB2® bind parameters for the read-only DDM come from the skeleton bind member that you specify in the mapping defaults panel 3, shown in Specifying mandatory defaults panel 2. The read-only DDM is automatically generated when you generate the DIM and read-write DDM.
See VSAM file DD statement changes for the JCL changes that are required to use the read-only DDM at run time.