A distributed database is stored in multiple physical locations and distributed at various sites of an organization. The sites are connected with the help of communication links, so the user can access the distributed data easily. There are two kinds of distributed database—homogeneous and heterogeneous. In a homogenous distributed database, the physical locations have the same hardware and run in the same OS and database applications. However, in the heterogeneous distributed database, the hardware, OS, or database applications can be found in a different location.