Distributed database management system

A distributed database management system ('DDBMS') is a software system that permits the management of a distributed database and makes the distribution transparent to the users. A distributed database is a collection of multiple, logically interrelated databases distributed over a computer network. Sometimes "distributed database system" is used to refer jointly to the distributed database and the distributed DBMS.A distributed database system consists of loosely coupled sites that share no physical component.Database systems that run on each site are independent of each other.

Overview

Distributed database management systems is a software for managing databases stored on multiple computers in a network. A distributed database is a set of databases stored on multiple computers that typically appears to applications on a single database. Consequently, an application can simultaneously access and modify the data in several databases in a network.A DDBMS mainly classified into two types Homogeneous DDBMS Heterogeneous DDBMS

Characteristics

All sites are interconnected. Fragments can be replicated. Logically related shared data can be collected. Data at each and every site is controlled by the DBMS. Each DDBMS takes part in at least one global application.

Functionality

Security Keeping track of data Replicated data management System catalog management Distributed transaction management Distributed query processing Distributed database recovery

Homogeneous DDBMS

All sites have identical software and are aware of each other and agree to cooperate in processing user requests. Each site surrenders part of its autonomy in terms of right to change schema or software. Homogeneous DDBMS appears to user as a single system.

See also

• Heterogeneous Database System

References

• M. T. Özsu and P. Valduriez, Principles of Distributed Database Systems (2nd edition), Prentice-Hall, 1999. ISBN 0-13-659707-6.