International Journal of Computer Science and Mobile Computing (IJCSMC)
In distributed database the data is physically stored on two or more computer systems, so DDBMS allow to manages or organize the whole database as a single collection of data as result the individuals able to access data from any of the database system because the replication of the data among all the systems in the network. A distributed database may be partitioned and replicated in addition to being distributed across multiple sites. All of is not visible to the users. In this sense, the distributed database technology extends the concept of data independence, which is a middle conception of database management, to situation where data are distributed and replicated over a number of machines connected by a network.