Expandable subfiles in RPGLE

An expandable subfile is one in which ideally one page of records are loaded at a time. Subsequent pages are added to the subfile as per the user demand.

In the expandable subfile the subfile size must be atleast one greater than the page size.

The ILE RPG program to process an expandable subfile has typically the following flow

 So far we have dealt with display only subfiles. Now we will learn the subfiles which can accept user input and process it.

Generally the following are the steps in which we can display and process an input capable subfile. The editable subfiles are very much similar to the display-only subfiles except the last two steps where these subfiles are read (USING READC Or CHAIN) and updated (Using UPDATE). The steps to process an editable subfile in RPG IV are as given below.

Free Tutorial on AS400 Subfiles in ILE RPG (RPG-IV)

After learning the basic concepts of ILE RPG IV an RPG programmer's next stop is Subfiles. AS/400 Subfiles should always be learnt after one has acquired basic skills of RPG IV. One should be able to understand the basic RPG IV concepts like Processing display files, Record Formats, Physical Files, Logical Files, How to interact with database files and finally how to process an interactive display file. 

Introduction to subfiles

Basically subfiles are display-file-concept. Whenever we have to display some tabular data we have two options

# Define as many required fields