Replication is the process of copying and maintaining database objects in multiple databases that make up a distributed database system. Replication can improve the performance and protect the availability of applications because alternate data access options exist. For example, an application might normally access a local database rather than a remote server to minimize network traffic and achieve maximum performance. Furthermore, the application can continue to function if the local server experiences a failure, but other servers with replicated data remain accessible.
Oracle supports two different forms of replication: basic and advanced replication:
1- Basic Replication
With basic replication, data replicas provide read-only access to the table data that originates from a primary (master) site. Applications can query data from local data replicas to avoid network access regardless of network availability. However, applications throughout the system must access data at the primary site when updates are necessary.
2- Advanced (Symmetric) Replication
The Oracle advanced replication features extend the capabilities of basic read-only replication by allowing applications to update table replicas throughout a replicated database system. With advanced replication, data replicas anywhere in the system can provide both read and update access to a table's data. Participating Oracle database servers automatically work to converge the data of all table replicas, and ensure global transaction consistency and data integrity.
Oracle supports two different forms of replication: basic and advanced replication:
1- Basic Replication
With basic replication, data replicas provide read-only access to the table data that originates from a primary (master) site. Applications can query data from local data replicas to avoid network access regardless of network availability. However, applications throughout the system must access data at the primary site when updates are necessary.
2- Advanced (Symmetric) Replication
The Oracle advanced replication features extend the capabilities of basic read-only replication by allowing applications to update table replicas throughout a replicated database system. With advanced replication, data replicas anywhere in the system can provide both read and update access to a table's data. Participating Oracle database servers automatically work to converge the data of all table replicas, and ensure global transaction consistency and data integrity.