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Keyed Backward Processing

Processing Method

VSAM keyed backward processing accesses records sequentially in descending order from a specified position in the file. The starting position in the file can be established with a POINT call either on a prime key or on a relative-record number. Backward processing cannot be used with SKP-sequential processing.

DML Commands

CA IDMS VSAM Transparency translates VSAM calls for keyed backward processing into the following commands:

• A POINT call is translated into the FIND WITHIN SET USING SORTKEY DML command.
• A GET call is translated into the OBTAIN LAST/PRIOR WITHIN SET DML command.