Data Replication is the process of storing data in more than one site or node. It is useful in improving the availability of data. It is simply copying data from a database from one server to another server so that all the users can share the same data without any inconsistency. There are three types of data replication.They are:1.Snapshot Replication 2.Transactional Replication 3.Merge Replication 1.Snapshot Replication :Snapshot replication simply takes a "snapshot" of the data on one server and moves that data to another server 2.Transactional Replication:Transactional replication involves copying data from the publisher to the subscriber(s) once and then delivering transactions to the subscriber(s) as they occur on the publisher. 3.Merge Replication:Merge replication combines data from multiple sources into a single central database. Much like transactional replication, merge replication uses initial synchronization by taking the snapshot of data on the publisher and moving it to subscribers.
Ans: To improve the availability of data, data may be replicated at multiple sites by copying the data in multiple places.there are three basic ideas no replication, full replication and partial replication.