Structured Query Language (SQL) procedures, triggers, and functions, which are also known as user-defined functions (UDFs), are the key database features for developing robust and distributed applications. IBM® DB2® for i supported these features for many years, and they are enhanced in IBM i versions 6.1, 7.1, and 7.2. DB2 for i refers to the IBM DB2 family member and relational database management system that is integrated within the IBM Power operating system that is known as IBM i. This IBM Redbooks® publication includes several of the announced features for SQL procedures, triggers, and functions in IBM i versions 6.1, 7.1, and 7.2. This book includes suggestions, guidelines, and practical examples to develop DB2 for i SQL procedures, triggers, and functions effectively. This book covers the following topics: Introduction to the SQL/Persistent Stored Modules (PSM) language, which is used in SQL procedures, triggers, and functions SQL procedures SQL triggers SQL functions This book is for IBM i database engineers and data-centric developers who strive to provide flexible, extensible, agile, and scalable database solutions that meet business requirements in a timely manner. Before you read this book, you need to know about relational database technology and the application development environment on the IBM Power Systems™ with the IBM i operating system.

In 1978 IBM introduced the System/38 as part of its midrange platform hardware base. One of the many outstanding features of this system was the built-in Relational Database Management System (RDMS) support. The system included a utility for defining databases, screens, and reports. This utility used a form named Data Description Specifications (DDS) to define the database physical (PF) and logical (LF) files (base tables, views, and indexes). In 1988, IBM announced the AS/400. The OS/400 operating system also contained a built-in RDMS, however, IBM offered Structured Query Language (SQL) as an alternative to DDS for creating databases. In addition, SQL Data Manipulation Language (DML) statements were made available as an ad hoc query language tool. These statements could also be embedded and compiled within high level language (HLL) programs. SQL Data Definition Language (DDL) has become the industry standard for defining RDMS databases. Many customers are in the process of modernizing their database definition and the database access. This IBM Redbooks publication will help you understand how to reverse engineer a DDS-created database along, and provides you with tips and techniques for modernizing applications to use SQL as the database access method. Additional Resources on DB2 for i Modernization: