Book Image

IBM DB2 9.7 Advanced Application Developer Cookbook

Book Image

IBM DB2 9.7 Advanced Application Developer Cookbook

Overview of this book

With lots of new features, DB2 9.7 delivers one the best relational database systems in the market. DB2 pureXML optimizes Web 2.0 and SOA applications. DB2 LUW database software offers industry leading performance, scale, and reliability on your choice of platform on various Linux distributions, leading Unix Systems like AIX, HP-UX and Solaris and MS Windows platforms. This DB2 9.7 Advanced Application Developer Cookbook will provide an in-depth quick reference during any application's design and development. This practical cookbook focuses on advanced application development areas that include performance tips and the most useful DB2 features that help in designing high quality applications. This book dives deep into tips and tricks for optimized application performance. With this book you will learn how to use various DB2 features in database applications in an interactive way.
Table of Contents (15 chapters)
IBM DB2 9.7 Advanced Application Developer Cookbook
Credits
About the Authors
About the Reviewers
www.PacktPub.com
Preface

Creating a sequence object


Many applications require sequential numbers to be generated for key values such as the item number, invoices, and so on. Sequences offer a very good solution to such applications. Sequences are database objects that allow a user to generate key values automatically. Because these values are generated within the database, there is no chance of the duplicate values being present. DB2 keeps track of the values being generated and knows the next values, so even in the case of a crash or a failure, the new values are correct. It also gives better performance as compared to other approaches of generating the values manually. In this recipe, we will see how sequences can be created and used, and we will also see how it is different from an identity column. In this recipe, we will see how to create sequence objects.

Getting ready

The key aspect to consider before creating a sequence is the sequence behavior. DB2 automatically increments the sequence value based on the...