Friday, October 9, 2009

Database Replication - SQL

What is Database Replication?

It is a kind of Data Transformation Services and it is responsible for the process of copying/moving the data among the databases which may be in same or different server.

What are the Types of Replication available in SQL?

Replications are classified into following categories based on process it involved.

* Snapshot replication
* Transactional replication
* Merge replication

Snapshot replication:

It will distribute the data exactly from one database to another. It won’t monitor any changes like updating, deletion etc.., it can be used when data are infrequent. . It is often used for browsing data such as price lists, online catalog, or data for decision support where the current data is not required and data is used as read only.

Transactional replication:

Initially, it will start with snapshot replication, and then whenever data changes happen, it will capture the changes and the changes will be propagated to the subscribers.

Merge replication:

Merge replication is bit different than others, it is a 2 way process. This process distributing the data between publisher and subscriber, it allows the publisher and subscriber to update the data while connected or disconnected, and then merging the updates between the sites when they are connected.

1 comment:

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