Additional DD statement for dummy VSAM data set

PL/I and COBOL use undocumented interfaces to invoke the VSAM SHOWCB and TESTCB macros. To provide this support in CICS® VT, you must create a new VSAM data set and add one additional DD statement for each base cluster and alternate index path to your batch JCL.

If you use the data migration generation utility, run the member VID4DUMM in the generated appl.dimname.migrate library to create the dummy VSAM data set. If you don't use the data migration generation facility, you must create the dummy data set manually.

Model the dummy data set cluster on the cluster for the original VSAM data set, with minimum space allocated. Figure 1 is an example data set that uses the definition for the cluster that was used in The mapping component .

Figure 1. Define CLUSTER for dummy VSAM data set
 DEFINE  CLUSTER                                   
           (NAME(VID.VIDKSDS.VID)                  
            INDEXED SHR(2 3))                      
         DATA                                      
           (NAME(VID.VIDKSDS.VID.DATA)             
            KEYS(6 0) VOL(CTC002) RECSZ(80 80)     
            CISZ(16384) TRK(1))                    
         INDEX                                     
           (NAME(VID.VIDKSDS.VID.INDEX)            
            CISZ(2048) VOL(CTC002) TRK(1))   

Initialize the dummy data set with one record. Sample JCL using the Access Method Services IDCAMS utility follows:

//VIDCOPY EXEC PGM=IDCAMS,REGION=1M             
//SYSPRINT DD  SYSOUT=*                         
//INF      DD  DISP=SHR,DSN=VID.VIDKSDS    
//OUTF     DD  DISP=SHR,DSN=VID.VIDKSDS.VID
//SYSIN    DD  *                                
 REPRO INFILE(INF) OUTFILE(OUTF) COUNT(1)
You must add a new DD statement for this copy of the VSAM data set to your batch JCL for the base cluster data set and each alternate index. Use the dummy VSAM data set name for both the base cluster statement and alternate index path DD statements. The DD name you must use is derived from the DD statement for your real VSAM data set as follows:
Examples of both DD statements are shown in the following sample JCL: Start of change
//STEPLIB  DD DSN=appl.prog.lib,DISP=SHR
//         DD DSN=appl.DRIVERS.LOAD,DISP=SHR
//         DD DSN=VID.SVIDLODE,DISP=SHR  
//ITEMDET  DD SUBSYS=(ssi,db2id,dimname)
//ITEMDET@ DD DSN=ITEMDET.VID.DUMMY,DISP=SHR   
//ITEMDETX DD SUBSYS=(ssi,db2id,aix-dimname)
//@TEMDETX DD DSN=ITEMDET.VID.DUMMY,DISP=SHR   
//ORDERDET DD SUBSYS=(ssi,db2id,dimname)
//@RDERDET DD DSN=ORDERDET.VID.DUMMY,DISP=SHR
End of change In this example, ITEMDET is the DD statement for the base cluster, and ITEMDETX is the DD statement for an alternate index path. The dummy VSAM data set should be defined to CICS. This is covered in Disabling access to a VSAM data set.

You can choose your own rules for the dummy VSAM data set DD name by adding appropriate code to the CICS VT user exit VIDDDMEX.


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Timestamp icon Last updated: Monday, 10 February 2014


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