About Materialized View Replication

Replication is the process of sharing database objects and data at multiple databases. To maintain replicated database objects and data at multiple databases, a change to one of these database objects at a database is shared with the other databases. In this way, the database objects and data are kept synchronized at all of the databases in the replication environment.

In many environments, such as field sales, databases are not connected to the network for periods of time. In these environments, replicas must synchronize data on demand, or at regularly scheduled intervals, such as nightly. These databases can synchronize with other databases that share the same data when they are reconnected to the network.

To address these needs, Oracle Database offers a replication type called materialized view replication. A materialized view contains a complete or partial copy of a table from a single point in time. Materialized views can be either read-only or updatable:

• Read-only materialized views provide read-only access to the table copy. Using read-only materialized views, applications and users can access local copies of tables that reside at remote locations. Read-only materialized views provide local access to data and reduce the resources required at any single location by allowing queries on the same data at multiple locations. For example, read-only materialized views are typically used for reporting purposes.

• Updatable materialized views provide read/write access to the table copy. Using updatable materialized views, applications and users can change both the table and the copy of the table, and these changes can be synchronized at a point in time. For example, updatable materialized views are typically used to periodically disseminate a product catalog to regional offices and to enable the sales force to place orders from customer sites.

Because of their support for easy mass deployment and disconnected computing, both read-only and updatable materialized views are especially suited to mobile computing applications.

The following topics provide more information about materialized view replication:

• About Master Sites, Master Tables, and Materialized View Sites

• About Materialized View Refresh

• About Refresh Groups