DB2 for i: The Database That's Already Built Into Your Operating System

Ask a developer coming from another platform how their database relates to their operating system, and you'll typically hear about a separate installation, a server process to manage, and a connection string to configure. On IBM i, that entire conversation doesn't apply — DB2 for i is integrated directly into the operating system itself, with no separate install step and no independent server process to keep running.

That tight integration is part of why IBM i has such a strong reputation for reliable, high-performance data processing. The database isn't a bolt-on component competing for resources alongside the rest of the system; it's a core part of the platform's architecture, which is also why RPG's embedded SQL support feels so natural rather than feeling like a bridge between two separate technologies.

Within DB2 for i, a handful of core object types matter most for day-to-day development. Tables store the actual rows of data — customer records, transaction history, inventory counts, whatever the application is built around. Views provide a stored, virtual result set built on top of one or more tables, letting developers or reports work with a simplified or filtered representation of the underlying data without duplicating it. Indexes exist purely for performance, giving the database engine a faster path to locate specific rows without scanning an entire table.

Journaling is the piece that's easy to overlook until something goes wrong. A journal captures a record of changes made to database data, and that record serves two critical purposes: it supports recovery after a system failure, and it enables commitment control, letting a set of related database changes be treated as a single all-or-nothing unit of work. Most production applications handling financial or transactional data depend on journaling being configured correctly, whether or not the developers working on that application think about it day to day.

For an RPG developer, understanding these fundamentals isn't optional groundwork to skim past — it's the foundation that embedded SQL, cursors, and later lessons on advanced query patterns all build directly on. A developer who understands what a table, view, index, and journal actually are, and why each exists, writes noticeably better SQL than one who's only ever memorized syntax.

This lesson is Lesson 8 of IBM i Platform Foundations in IBM i ILE RPG Mastery, setting up the database fundamentals that the course's embedded SQL lessons rely on.