CA IDMS/DB Schema and VSAM File Correspondences › Alternate Index › Record and Set Representations

Record and Set Representations

In an CA IDMS/DB database, an alternate index corresponds to a system-owned indexed set sorted on the alternate key. Index maintenance is performed automatically for all CA IDMS VSAM Transparency alternate indexes. The VSAM UPGRADE set is not applicable to CA IDMS VSAM Transparency.

To represent a VSAM alternate index in the CA IDMS/DB database, you must include the following definitions in the schema:

• The record type whose description corresponds to the base KSDS or ESDS. Note that the base KSDS or ESDS must already be defined in the schema.
• An indexed set whose owner is SYSTEM and whose member record represents the base KSDS or ESDS.
• A set order of SORTED (on the alternate key).
• For nonunique alternate indexes, a duplicates option of LAST.
• For unique alternate indexes, a duplicates option of DUPLICATES NOT ALLOWED.