Runtime Operations › Application Preparation › Step 1: Modify the Application JCL

Step 1: Modify the Application JCL

Two DD or DLBL Statements for Each File

Each ddname (z/OS) or filename (z/VSE) must be unique for an application program. This means that in local mode, you will have two DD or DLBL statements for each file:

• One statement must describe the ddname or filename specified in the assembler ACB, COBOL SELECT statement, or PL/I DECLARE statement.
• The other statement must describe the external file name specified in the CA IDMS/DB DMCL.

Example

Suppose a VSAM application program contains this COBOL SELECT statement:

SELECT CUSTFILE ASSIGN TO SYS030.

And suppose the DMCL definition of the VSAM data structure contains this file assignment:

ADD FILE CUSTOMER-FILE ASSIGN TO CSTFILE.

The JCL used to run the VSAM application in local mode will include one DD or DLBL statement for each of the files described above:

//SYS030 DD SUBSYS=(ESVS,'FMT=fmtname','SUBSCHEMA=ssname', ... )
//CSTFILE  DD DSN=CUST-FILE,DISP=SHR

Instructions for modifying the application JCL in z/OS and z/VSE are presented below.