Variable-Length Record Considerations › Using Variable-Length CA IDMS VSAM Transparency Records

Using Variable-Length CA IDMS VSAM Transparency Records

You must follow these steps to use a variable-length CA IDMS VSAM Transparency record:

1. Define the VSAM data structure to the CA IDMS/DB schema. In general, you define this data structure in the same way that you define a VSAM data structure that does not contain variable-length records.

   Additionally, you should do the following when you define the VSAM data structure to the CA IDMS/DB schema:

   • Define the records as variable. You do this by using the MINIMUM ROOT LENGTH and MINIMUM FRAGMENT LENGTH clauses of the schema ADD RECORD Data Description Language (DDL) statement.
   • Specify that the CA IDMS VSAM Transparency variable-length record procedure (ESVSPVLR) will be called at runtime. You do this by using the CALL clause of the ADD RECORD statement, as follows:

     CALL ESVSPVLR AFTER GET
     CALL ESVSPVLR BEFORE STORE
     CALL ESVSPVLR BEFORE MODIFY
     

     More information:

     For a complete description of the ADD RECORD statement, refer to CA IDMS Database Administration Guide.

2. Specify the maximum length of the variable-length record to the FMT compiler. You specify this value by using the VARIABLE UP TO option of the VSAM RECORD LENGTH IS statement. The record length can be obtained from the MAXLRECL field of the corresponding VSAM LISTCAT.

   More information:

   For more information on FMT syntax, refer to Preparing Control Information.

3. Include an ADD PROGRAM statement for ESVSPVLR in the DC/UCF system definition of all DC/UCF systems to be used with CA IDMS VSAM Transparency. Specify the ADD PROGRAM statement as follows:

   ADD PROGRAM ESVSPVLR
    LANGUAGE IS ASSEMBLER
    REENTRANT
    RESIDENT.
   

   Note: As part of the normal installation process for CA IDMS VSAM Transparency, your system definition will be updated with the definition of all programs required for this product. If you need to add these definitions to another system, source module DLODEVSM in your installed library contains the definition of all the CA IDMS VSAM Transparency programs.