EZTRIEVE programming language supplement

EZTRIEVE is supported in API mode only, using QUICKSAM CALLs for sequential I/O.

Refer to COBOL-programming-language-supplement in this manual for overall strategies for incorporating QUICKSTART into an application program. This Section is meant to function as a supplement to COBOL-programming-language-supplement to address specifics of the EZTRIEVE programming language and to present EZTRIEVE coding examples.

There are three primary deviations from normal EZTRIEVE coding styles when incorporating QUICKSTART into EZTRIEVE application programs:

• In lieu of using EZTRIEVE statements to read from or write to sequential files, the EZTRIEVE program issues CALLs the QUICKSAM API. This allows QUICKSTART to accurately track the status of sequential files for proper repositioning, should there be a need for a restart at some later time.
• In lieu of executing a DBMS checkpoint, the EZTRIEVE program PERFORMs CKPTRTN, which manages the necessary coordination between the DBMS, the program data, and the QUICKSAM-controlled sequential files.
• Application programs must incorporate into their design the concept of the Logical Unit of Work. Note that most batch application programs already incorporate this design feature, since it is frequently used in conjunction with issuing any necessary DBMS “COMMIT” activity.

A truly restartable application program must allow QUICKSTART to issue all necessary checkpoints, to include checkpointing of the Checkpoint Area, and to control all sequential file operations. This Section deals with how the application program must incorporate the services of QUICKSTART to ensure restartability.

See sample programs EZTDB2 and EZTIMS in the SAMPLIB for programming examples for DB2 and IMS respectively.

This section contains the following topics: