Chapter 1. Introduction

The DB2 Universal Database (DB2 UDB) refers to a family of database products:

• DB2 for Linux, UNIX, and Windows (distributed platforms, also referred to as DB2 LUW)

• DB2 for iSeries

• DB2 for z/OS (also referred to as DB2 zSeries)

Although each of these products have their own code base (which has been highly optimized for its intended hardware), application development and SQL support is fairly consistent across the platforms. All of these database products also support the DB2 SQL Procedural Language (SQL PL) but to varying degrees.

In the first edition of this book, we focused only on distributed platforms and have received very positive feedback on the approach we took to teach the SQL PL language. In this second edition, we expand our focus to include the rest of the DB2 family.

You can appreciate the difficulties of discussing a language in the context of three different development environments. Each platform has unique optimizations, and calling out the subtle (but important) differences can make it difficult to keep the discussion concise. We've worked hard to make this text an easy and enjoyable read. To that end, the approach we take is to describe each SQL PL feature as supported on DB2 for Linux, UNIX, and Windows platforms, and highlight the differences that may exist on the other platforms.

Before we begin, let's set up an SQL PL development environment.