This manual guides you through the process of planning and executing migrations, upgrades, and downgrades on the Oracle database system. In addition, this manual provides information about compatibility, about upgrading applications to the current release of Oracle, and about important changes in the current release, such as initialization parameter changes and data dictionary changes.Oracle9i Database Migration contains information that describes the features and functionality of the Oracle9i (also known as the standard edition) and the Oracle9i Enterprise Edition products. Oracle9i and the Oracle9i Enterprise Edition have the same basic features. However, several advanced features are available only with the Enterprise Edition, and some of these are optional. For example, to use application failover, you must have the Enterprise Edition with the Oracle9i Real Application Clusters option.