Oracle Database 10g Release 2  is available in several editions outlined below:

• Oracle Database 10g Express Edition—a starter database for DBAs and developers. Being completely free of charge, this no-frills edition of Oracle Database supports up to 4 GB of user data and executes on one processor only. Built on the same core code as Oracle Database 10g Release 2, Express Edition provides the same set of integrated programming interfaces available in the other editions of Oracle Database 10g and can be easily upgraded to Standard or Enterprise Edition.
• Oracle Database 10g Standard Edition One—a full-featured Oracle database that is ideal for small- to-medium-sized business environments. Standard Edition One provides the proven performance, ease of use, reliability and security of Oracle Database at a low cost. It can only be licensed on servers supporting up to two CPUs.
• Oracle Database 10g Standard Edition—an ideal choice for medium-sized business environments. Unlike Standard Edition One, Standard Edition supports Real Application Clusters, an Oracle technology that enables the clustering of the Oracle Database, comprising several Oracle instances running on multiple clustered computers so that they operate as a single system. Standard Edition can be licensed on single or clustered servers with up to four processors.
• Oracle Database 10g Enterprise Edition—ideal for enterprises that have to operate on large amounts of information. Enterprise Edition contains all of the components of the Oracle Database, offering enterprise-class performance as well as reliable and secure data management for mission-critical applications.

You can choose the edition of Oracle Database that best suits your needs and budget. As for the examples provided in this book, they should work with any of the above editions, including Oracle Database Express Edition. Unless otherwise noted, all examples provided in this book will work with Oracle Database 10g Release 2, or higher, irrespective of its edition.