AS/400 Programming Overview

🧠Overview of AS/400 Programming

Aspect	Description
Platform	IBM AS/400 (now IBM i)
Main Languages	RPG, CL, COBOL, SQL, Java
Database	DB2/400 (integrated relational DB)
Interface	Green-screen terminal (5250) and modern GUI/web interfaces
Tools	IBM Rational Developer for i (RDi), SEU, PDM

The primary and most common AS/400 programming language.

Variants: RPG III, RPG IV, and modern Free-Format RPG (RPGLE)

✅ Free-Format RPG Example:

**FREE
ctl-opt dftactgrp(*no) actgrp('MYPGM');

dcl-s msg varchar(50);

msg = 'Hello, AS/400!';
dsply msg;

*inlr = *on;
return;

Used for scripting, job control, and calling programs.

✅ CL Example:

PGM
DCL VAR(&NAME) TYPE(*CHAR) LEN(10)
CHGVAR VAR(&NAME) VALUE('IBMUSER')
SNDPGMMSG MSGID(CPF9898) MSGF(QCPFMSG) MSGDTA('Hello' *BCAT &NAME)
ENDPGM

You can write SQL in interactive SQL or embed it in RPG/CL.

✅ SQL Example:

SELECT * FROM EMPLOYEES WHERE DEPARTMENT = 'IT';

Component	Description
Libraries	Containers for related objects (like folders)
Objects	Everything on AS/400 is an object: files, programs, etc.
Physical File (PF)	Like a table
Logical File (LF)	Like a view/index
Data Areas/Queues	Shared memory or communication between programs
Job/Job Queue	How tasks are scheduled and run

Tool	Use
SEU (Source Entry Utility)	Edit source code (old style)
PDM (Program Development Manager)	Navigate/edit source
RDi (IBM Rational Developer for i)	Modern Eclipse-based IDE
ACS (Access Client Solutions)	Modern GUI for database and terminal