A distributed database is a database in which parts of the database are stored in multiple physical locations and processing is distributed among several database nodes. A centralized distributed database management system (DDBMS) integrates the data logically so that it can be managed as if it were all stored in the same location. The DDBMS synchronizes all data periodically and ensures that updates and deletions made to the data in one location will be automatically reflected in the data stored elsewhere.
Distributed databases can be homogeneous or heterogeneous. In a homeogenously distributed database system, all physical locations have the same underlying hardware and run the same operating systems and database applications. In a heterogeneous distributed database, hardware, operating systems, or database applications may be different in each of the locations.
A distributed database is a database in which the storage devices are not all connected to a common processor. It can be stored on several computers, located in the same physical location; Or they can be dispersed over a network of interconnected computers. Unlike parallel systems, where processors are tightly coupled and constitute a single database system, a distributed database system consists of loosely coupled sites that do not share physical components.
System administrators can distribute data collections (for example, in a database) to multiple physical locations. A distributed database can reside on organized network servers or on decentralized independent computers on the Internet, on corporate intranets or extranets, or on other organizational networks. Because distributed databases store data across multiple computers, distributed databases can improve performance on end-user workstations by allowing transactions to be processed on many machines, rather than limited to one.