Oracle Essentials: Oracle9i, Oracle8i and Oracle8, Second Edition

Data Movement Features

Moving data from one Oracle database to another is often a requirement when using distributed databases, or when a user wants to implement multiple copies of the same database in multiple locations to reduce network traffic or increase data availability. You can export data and data dictionaries (metadata) from one database and import them into another. Oracle also offers many other advanced features in this category, including replication, transportable tablespaces, and Advanced Queuing.

This section describes the technology used to move data from one Oracle database to another automatically.

Basic Replication

You can use basic replication to move recently added and updated data from an Oracle “master” database to databases on which duplicate sets of data reside. In basic replication, only the single master is updated. You can manage replication through the Oracle Enterprise Manager (OEM prior to Oracle9i, EM in Oracle9i).

Advanced Replication

You can use advanced replication in multimaster systems in which any of the databases involved can be updated and conflict-resolution features are needed to resolve inconsistencies in the data. Because there is more than one master database, the same data may be updated on multiple systems at the same time. Conflict resolution is necessary to determine the “true” version of the data. Oracle’s advanced replication includes a number of conflict-resolution scenarios and also allows programmers to write their own. We cover ...