RPG Programming Language
If you are a programmer and you are interested in learning how to program on the AS/400 system, you should know that the main language is RPG.
The “Report Program Generator” has evolved considerably since version 2, which was also used on the IBM “Sistemi 36” (another pre-era AS/400 calculator).
Over time it has gone through version III and IV. The latest version released is the “Free” version, that is without fixed format in the code queue that is much more convenient to use.
However, it remains a procedural language without support at least natively, for graphic libraries but only for the character interface mentioned above. The GUI is built using Java, PHP or third-party tools.
You can also program in Cobol and many other languages (Java, C, etc.) even if the application part with the business logic is almost always in RPG.
RPG is made attractive by a huge legacy of applications written in this language.
Strong is the use of SQL. Both as interactive executions for changes to the DB, integrated in programs or used in stored procedures.
The DB2/400 is the only usable database on the AS/400. Extremely integrated with the operating system, so much so that it sometimes results in a single entity.
DB2/400 supports triggers, referential integrity, static or dynamically constructed logical views (indexes), and generally supports almost all of the operating mechanisms of modern databases.
If you want to study programming in RPG at level IV, at the following link www.neroni.it/Scaricabili/CorsoRpg.pdf you can find an open source RPG manual in Italian written and kindly offered by Mr. Claudio Neroni, IT consultant on AS/400 systems.
It also deals with issues related to the use of the AS/400 system in general and the utilities supporting programming (video construction, prints, commands, etc.).
From the IBM website (or, by performing a network search), you can download the hardware and software manuals (languages, tools and operating system) of the AS/400. Particularly interesting are the “Red Books”, manuals that deal with advanced technical issues.