A distributed database is a collection of databases which are distributed over different computers of a computer network.

Advantages:

  1. Local Autonomy: permits setting and enforcing local policies regarding the use of local data (suitable for organization that are inherently decentralized).
  2. Improved Performance: The regularly used data is proximate to the users and given the parallelism inherent in distributed systems.
  3. Improved Reliability/Availability: Data replication can be used to obtain higher reliability and availability.
    The autonomous processing capability of the different sites ensures a graceful degradation property.
  4. Incremental Growth: supports a smooth incremental growth with a minimum degree of impact on the already existing sites.
  5. Shareability: allows preexisting sites to share data.
  6. Reduced Communication Overhead: The fact that many applications are local clearly reduces the communication overhead with respect to centralized databases.