How to use the Datacom CICS Services DBID Remapping Feature

Document ID : KB000027707
Last Modified Date : 14/02/2018
Show Technical Document Details

Introduction:

The Datacom DBID remapping feature allows you to switch the DBID priorto calling the Multi-User Facility (MUF) and then switch it back upon the return from MUF. This can be used when you want to switch your target DBID.

DBID remapping in CA Datacom CICS Services requires the implementation of a global User Requirements Table (URT).

The global URT was introduced in Datacom 11.0 and provides support for:

  • Multiple Multi-User Facility (MUF) support
  • DBID remapping support.

For DBID remapping support the following URT parameters are utilized:

    • Start Macro (DBURSTR)
      • SIDNAME= parameter must be specified
      • SIDNAME=DBSIDPR can be specified
    • Table Entry Macro (DBURTBL) - used to identify tables for navigational processing within this URT.
      • DBIDUSER= identifies the DBID that will be used for all communication with the application program.
      • DBIDMUF= identifies the DBID that will be passed to MUF for all application requests for the tables.

With the URT DBID remapping, the remapping of a DBID in a CICS region only requires a simple URT change.

 

Instructions:

There are a variety of reasons why you would want to remap a DBID. Here are just a few examples:

  • You have two production MUF regions (East and West). In each MUF, it has the same set of production databases. For all current processing, when a program/transaction is executed it runs against either the East or West MUF. However, a new requirement has just been received to allow a given CICS transaction to read data from the Accounts database (DBID 100) on both regions.

    • Utilizing multiple MUF support you can create a single CICS URT that will connect to both the East and West MUFs. This is accomplished by pairing a DBURSTR macro that selects the target MUF with the DBURTBL macro. However, since the accounts tables are known as ACC100 in both systems, there will be no way for the application program to direct or detect which MUF to process.

    • By adding a DBIDUSER= and DBIDMUF= parameter to set to one or both DBURTBL macros you will be able to select an alternate DBID for the processing on one or both systems.


    Figure 1

    Figure 2

    In the suggested implementation above, you would leave the existing URT defined to the CICS region. This would provide access for existing applications. Then add the two new global URTs to add support for ACC101 and ACC102 where ACC101 is the same as ACC100 in the EAST MUF and ACC102 is the same as ACC100 is the WEST MUF.

    Now a new program can be written that can access the two tables in one transaction and provide a combined report.

  • A database that has several tables. These tables have grown over the years, and you would like to separate the tables out into different DBIDs. However, there are  a significant number of user programs with the DBID hard coded as part of the database request area. By using the DBID remapping feature you can move one (or more) of the tables to a new DBID without having to recode the application programs. All that is needed is a simple change to the online URT.

    Figure 3

    Figure 4

In the suggested implementation above, you would be able to move the table to a new DBID without changing the applications. Tables having application that have shared keyids and use locate with DBID as the table name are not eligible for being moved to separate DBIDs.

 

Additional Information:

CA Datacom/DB Database and System Administrator Guide section  Defining a User Requirements Table (URT) or the CA Datacom documentation in docops.ca.com

CA Datacom for CICS Services System Reference Guide section  Coding the URT Macros or the CA Datacom Tools documentation in docops.ca.com