分布式数据库是用计算机网络将物理上分散的多个数据库单元连接起来组成的一个逻辑上统一的数据库。每个被连接起来的数据库单元称为站点或节点。分布式数据库有一个统一的数据库管理系统来进行管理，称为分布式数据库管理系统。

分布式数据库的基本特点包括：物理分布性、逻辑整体性和站点自治性。从这三个基本特点还可以导出的其它特点有：数据分布透明性、按既定协议达成共识的机制、适当的数据冗余度和事务管理的分布性。

分布式数据库按照各站点中数据库管理系统的数据模型的异同分为异构型分布式数据库和同构型分布式数据库，按照控制系统的类型分为全局控制集中性、全局控制分散型和全局控制可变型。

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.