Defining an IMS catalog alias name

When your IMS environment includes multiple IMS catalog databases, you differentiate between the IMS catalogs by assigning unique alias names to the IMS catalogs when they are first defined.

To support environments that require more than one IMS catalog, IMS can perform dynamic IMS catalog name aliasing on behalf of your application programs.

You do not need to make any modifications to your user PCBs, which always refer to the catalog database as DFSCD000 and the catalog secondary index as DFSCX000.

Alias names are not needed in a configuration where multiple IMS systems in an IMSplex can share a single IMS catalog that contains the metadata for the entire environment. In this configuration, every IMS system can use the standard catalog database name, DFSCD000, and the standard catalog secondary index name, DFSCX000.

The procedure for assigning an alias name to an IMS catalog is the same regardless of whether you intend to enable the IMS management of ACBs or you intend to manage your ACBs by using ACB libraries. If you are going to enable the IMS management of ACBs, even though the IMS system will not use ACB, DBD, and PSB libraries, you still must allocate and use DBD, PSB, and ACB libraries temporarily to enable the IMS catalog and assign the alias name.

Procedure

Create or modify the DFSDFxxx member of the IMS.PROCLIB data set with a <SECTION=CATALOG> or <SECTION=CATALOGxxxx> statement.
Include the ALIAS parameter with a valid, 4-character prefix other than DFSC.

Add alias names to the IMS catalog database name list in your IMS DBD library with the IMS Catalog Alias Names utility (DFS3ALI0).

Modify the following utility JCL for your environment:

//ALIAS  EXEC  PGM=DFS3ALI0   
   //STEPLIB  DD  DSN=IMS.SDFSRESL,DISP=SHR
   //DFSRESLB DD  DSN=IMS.SDFSRESL,DISP=SHR  
   //SYSPRINT DD  SYSOUT=* 
   //SYSLMOD  DD  DSN=IMS.DBDLIB,DISP=OLD
   //SYSLIN   DD  UNIT=SYSDA,SPACE=(CYL,(1,1))
   //SYSUT1   DD  UNIT=SYSDA,SPACE=(CYL,(1,1))    
   //SYSIN    DD  *  
  prefix1,prefix2,…
   /*

Define the new IMS catalog database in the RECON data set by using the Database Recovery Control utility (DSPURX00).

Modify the following utility JCL for your environment. This example uses the alias name IMS1:

//ALIAS1  EXEC PGM=DSPURX00   
  //STEPLIB  DD  DSN=IMS.SDFSRESL,DISP=SHR  
  //SYSPRINT DD  SYSOUT=*                   
  //IMS      DD  DSN=IMS.DBDLIB,DISP=SHR    
  //SYSIN    DD  *                          
   INIT.DB DBD(IMS1D000) TYPHALDB SHARELVL(3)
   INIT.PART DBD(IMS1D000) PART(IMS1D01) -   
     DSNPREFX(dsnprefix.IMS1D000) –
     BLOCKSZE(4096) -
     KEYSTRNG(X'FFFFFFFFFFFFFFFFFFFFFFFFFFFF')
   INIT.DB DBD(IMS1X000) TYPHALDB SHARELVL(3)
   INIT.PART DBD(IMS1X000) PART(IMS1X01) -    
     DSNPREFX(dsnprefix.IMS1X000)  - 
     KEYSTRNG(X'FFFFFFFFFFFFFFFFFFFFFFFFFFFF')      
  /*

Add ACB library metadata to the IMS catalog database with the IMS Catalog Populate utility (DFS3PU00).
The utility JCL must refer to the DFSDFxxx member that defines the alias name for the catalog.