This chapter provides an overview of the major steps required to migrate a pre-version 8 database to version 8.
These migration procedures transform an existing pre-version 8 database system (including associated applications) into a version 8 database system. Version 8 is compatible with all earlier Oracle versions and releases. Therefore, databases transformed using the migration procedures described in this book can work in the same manner as in earlier versions and, optionally, can leverage new version 8 functionality.
Several preparatory steps are required before you migrate the current production database. After migrating a database, you should perform several additional test steps to test the migration. Other procedures enable you to add new version 8 functionality to existing pre-version 8 applications.
The following topics are covered in this chapter:
The following terms are used throughout this document:
Migration is the process of transforming an installed version of an Oracle database into a later version. For example, transforming a version 7 database into version 8 is migrating the database system.
Upgrading is the process of transforming an installed version of an Oracle database from an installed release into a later release of the same version. For example, transforming release 8.0.3 into release 8.0.4 is upgrading.
Downgrading is the process of transforming an installed version of an Oracle database from a later release back into an earlier release. For example, transforming an Oracle database from release 8.0.4 back into release 8.0.3 is downgrading, and transforming an Oracle database from version 8 back into version 7 is downgrading.
Chapter 8, "Upgrading and Downgrading" for information about upgrading or downgrading.
The source database is the database to be migrated to version 8; typically, the source database uses an older version of Oracle software. The target database is the database into which you are migrating the source database; typically, the target database uses new version 8 software.
Before you perform a database migration, you should understand the major steps in the migration process. These major steps apply to all operating systems, with the possible exception of a few platform-specific details identified in your Installation Guide.
Careful planning and use of version 8 tools can ease the process of migrating a database to version 8. The Migration Utility is the easiest way to migrate an entire database, while Export/Import and SQL copy utilities enable piecemeal migration of parts of a database.
The migration process includes the following major steps:
The following sections contain a brief outline of these steps. The purpose of these descriptions is to familiarize you with the major steps in the migration process. For detailed instructions, refer to the appropriate sections later in this book.
Chapter 2, "Preparing to Migrate", provides detailed information about Steps 1 through 3.
Oracle8 Replication, Appendix B, "Migration and Compatibility", if you are migrating a pre-version 8 database system that has Advanced Replication installed.
Typically, the database administrator (DBA) is responsible for ensuring the success of the migration process. The DBA is usually involved in each step of the process, except for steps that involve testing applications on the migrated database.
The specific DBA duties typically include:
Users should not have access to the migrated version 8 database until after all applications have been tested and operate properly.
The application developer is responsible for ensuring that applications designed for the pre-migration version 7 database work correctly with the migrated version 8 database. Application developers often test applications against the migrated version 8 database and decide which available new features of version 8 should be used.
Before migrating the version 7 production database, the DBA or application developer should install a version 8 test database. Then, the application developer tests and modifies the applications, if necessary, until they work with their original (or enhanced version 8) functionality.
The following references provide information about identifying differences in the migrated version 8 database that could affect particular applications. Application developers can use these differences to guide modifications to existing applications.
Version 8 provides features that aid in upgrading existing applications to version 8: