Summary

This lesson has illustrated several areas of RPG IV File Declaration. To review what you've learned:

Files are declared using the File Description Specification, also called File Spec or F Spec.

There are two types of files that may be declared in RPG IV:

1. Externally Described
2. Program Described

SQL database tables and views may be used in RPG IV, but are not declared via the File Description Specification; embedded SQL is used instead.

There are 5 types of file devices that may be used by RPG IV:

1. DISK - Database files
2. PRINTER - Spooled/Print output files
3. WORKSTN - Display files
4. SPECIAL - User written sequentially processed files
5. SEQ - Sequential device files, normally used to read directly from a Tape drive or to process legacy 80-column punch cards.

Database files may be declared with keyed (random) or sequential access.

The Prefix keyword may be used to push the I/O buffer of an externally described file into a Qualified Data Structure, which can marginally improve I/O performance.

File and member names may be specified at runtime using the EXTFILE and EXTMBR keywords respectively.

If you want to learn more, you might consider this book from Amazon.com.

# # #