A heterogeneous distributed database is which of the following?

Solution (By Examveda Team)

A heterogeneous distributed database refers to a distributed database system where different Database Management Systems (DBMS) are used at different locations or nodes, and data are not necessarily distributed across all nodes.

Option A: The same DBMS is used at each location and data are not distributed across all nodes.
This scenario describes a homogeneous distributed database where the same type of DBMS software is used at each location, but the data may not be distributed across all nodes. In a homogeneous environment, data may still be centralized or distributed selectively based on the system's design and requirements.

Option B: The same DBMS is used at each location and data are distributed across all nodes.
This scenario also describes a homogeneous distributed database where the same DBMS software is used at each location, and data are distributed across all nodes. In such a setup, each node stores a portion of the distributed data, and the DBMS coordinates data access and management across the distributed environment.

Option C: A different DBMS is used at each location and data are not distributed across all nodes.
This option represents a heterogeneous distributed database where different DBMS software is used at different locations or nodes. In a heterogeneous environment, each node may have its own DBMS, which could be from different vendors or versions. However, data are not necessarily distributed across all nodes; they may be centralized or distributed selectively based on the system's architecture.

Option D: A different DBMS is used at each location and data are distributed across all nodes.
This scenario combines aspects of both homogeneous and heterogeneous distributed databases. It describes a heterogeneous environment where different DBMS software is used at each location, and data are distributed across all nodes. This configuration can introduce additional complexity due to the need for interoperability and data integration between disparate DBMS platforms.

Therefore, in the context of a heterogeneous distributed database, the correct option is A different DBMS is used at each location and data are not distributed across all nodes (Option C).