IDMSLRF

The IDMS Logical Record Facility presents a database view to the programmer; it constructs a logical record from a view into one or more databases. The database administrator determines which database records are affected by each program request for a logical record, which database access statements will be executed in the path, and what modifications are made to the database records involved.

An IDMS/R mode of operation allows multiple application programs that share a single DBMS to execute concurrently. It also provides for automatic recovery in the event of a program failure. LRF is the IDMS/R tool that facilitates database programming and allows access to fields from multiple database records as if they were data fields in a single record. LRF (also called non- navigational programming) lets you specify selection criteria so that you can access only those records you need by coding a single logical-record request; for example, to retrieve, delete, modify, or store the logical-record occurrence. The non-navigational programming environment provides you with a simple and efficient database access method.

Hints

Heavy CPU use might indicate that the database administrator needs to improve access path performance. The following two logical record facility (LRF) reports are most useful to application programmers:

  • LRDEFS lists records, supplies definitions of all fields and all DBA comments on such topics as restrictions placed on operations, selection criteria, and path status, which indicates the result of the requested operations.

  • LRPATH lists the records that participate in the logical record and all DBA- defined path groups that assist in the design of the application.

Reference Sources

IDMS-DB/DC Programmer's Guide, Cullinet, Release 10.0.