Learn RPG-IV-AS400 with Real Code Examples

RPG IV is widely used for enterprise business logic on IBM i systems.

Supports both fixed-format and free-form coding styles.

Integrates seamlessly with DB2 for IBM i database operations.

Used for transaction processing, reporting, and business applications.

Evolved from older RPG III to modernized syntax with modularization and service programs.

RPG IV compiler for IBM i

Modularization through procedures and service programs

Embedded SQL for DB2 integration

Structured exception handling

Integration with CL programs and IBM i utilities

Program - compiled RPG object on IBM i

Procedure - modular function within RPG IV

Service Program - reusable compiled library of procedures

File - physical or logical DB2 object for data storage

Data Structure - composite variable for complex data handling

Source physical files for RPG IV code

Modules or procedures grouped in service programs

DB2 files for data input/output

CL programs for batch execution or job control

Libraries and object directories for deployment

Analyze business requirement or transaction logic

Design program structure with procedures or modules

Write RPG IV code (fixed or free-form syntax)

Compile and test program using IBM i development tools

Deploy program to production library and integrate with workflows

Beginner: simple data reading/writing programs

Intermediate: modular procedures with DB2 queries

Advanced: batch processing with complex business logic

Expert: service programs and multi-module applications

Architect: enterprise-level transaction systems with IBM i integration

RPG IV vs RPG III: Free-form syntax and modularization

RPG IV vs COBOL on IBM i: RPG optimized for business apps, COBOL more general-purpose

Service programs vs modules: Reusable vs program-specific

RPG IV vs modern languages: Less flexible outside IBM i ecosystem

RPG IV vs CL: CL is for job control, RPG IV for business logic

1960s - RPG I introduced for punched card business applications

1970s - RPG II enhanced for IBM System/34

1980s - RPG III introduced for System/38 and AS/400

1994 - RPG IV (RPGLE) with free-form syntax released

2000s - Embedded SQL and service programs supported

2025 - Modern RPG IV free-form fully integrated with IBM i and DB2 enhancements

RPG IV / RPGLE - high-level programming language for IBM i

Procedure - reusable function in RPG IV

Service Program - library of procedures

DB2 - IBM i relational database

CL Program - control language for batch and job management