Users have access to the portion of the database at their location so that they can access the data relevant to their tasks without interfering with the work of others. A centralized distributed database management system (DDBMS) manages the database as if it were all stored on the same computer.
The DDBMS synchronizes all the data periodically and, in cases where multiple users must access the same data, ensures that updates and deletes performed on the data at one location will be automatically reflected in the data stored elsewhere. Distributed database is a database that is under the control of, a central database management system in which storage devices are not all attached to a common CPU.
Distributed database technology is one of the most important developments of the past decades. The maturation of data base management systems - DBMS - technology has coincided with significant developments in distributed computing and parallel processing technologies and the result is the emergence of distributed DBMSs and parallel DBMSs.