Oracle7 Server Distributed Systems Volume I: Distributed Data

Replication Transparency

The ability to insure reliable data replication is an extremely important (and potentially complex) factor in a distributed system. Data replication means that any given data object can have several stored representatives at several different sites and that, if each representative is potentially updatable, there must be a mechanism for insuring that all representatives reflect the changes.

Oracle7 provides two mechanisms for accomplishing transparent table replication in a distributed system. The basic replication that comes with the distributed option provides asynchronous table replication through snapshots (changes to an updatable master table are replicated on the read-only or updatable snapshot tables only at timed intervals). Alternatively the advanced replication option allows you to implement synchronous table replication (changes to any table are applied to all replicated copies immediately) through the Oracle Symmetric Replication Facility. In either case, table replication is transparent to users making changes to replicated tables.

See Oracle7 Server Distributed Systems, Volume II for detailed information about all forms of replication.