gtpc3m1jConcepts and Structures

Record IDs

Record IDs are used within the TPF system to ensure and validate database integrity. Every record in the system, whether fixed or pool, must be associated with a two-byte record ID.

A record ID is placed in each fixed record when the database is initialized, and in each pool record by application programs as these records are acquired.

This record ID is given as a parameter within a file address reference word (FARW) of the entry control block (ECB) when a record is accessed with a find or file type macro request. Database integrity is ensured and validated because the record ID within a data record is compared with the record ID that is given as a parameter in the FARW when a record is accessed with a find or file macro. If the comparison fails, the access request is not valid.

Record ID Attribute Table (RIAT)

The record ID attribute table (RIAT) is a system table that holds the information about data organization that is necessary for data management by the TPF system. The RIAT is organized by and accessed by record ID. The RIAT contains information for both fixed records and pool records, such as:

A record ID must be specified for each pool record type (such as SSTx or LDPx) incorporated in a TPF system. This RIAT item is used to identify the appropriate pool record type when a get file storage macro request is invoked to obtain a pool record. In addition, the RIAT contains the following additional information about pool records: