A
distributed database is a
database in which
storage devices are not all attached to a common processing unit such as the
CPU, and which is controlled by a distributed
database management system (together sometimes called a distributed database system). It may be stored in multiple
computers, located in the same physical location; or may be dispersed over a
network of interconnected computers. Unlike parallel systems, in which the processors are tightly coupled and constitute a single database system, a distributed database system consists of loosely coupled sites that share no physical components.