NATURAL programming language supplement

Refer to COBOL-programming-language-supplement 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 NATURAL programming language and to present NATURAL coding examples.

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

• In lieu of specifying NATURAL 'READ WORK FILE' and 'WRITE WORK FILE' Statements for READing from or WRITing to sequential files, the NATURAL program issues “CALLs” to QUICKSAM to perform the necessary READs from, and WRITEs to, the appropriate sequential files. 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 issuing an “END TRANSACTION” to the appropriate DBMS to perform a checkpoint, the NATURAL program Performs CKPT-RTN, which manages the necessary coordination between the DBMS, the Defined 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.

Copy the example NATURAL program provided (see member NATDEMO in the QSTART.SAMPLIB). This provides the basic structure of a program that performs DBMS updates and sequential files accesses.

This section contains the following topics: