What characterizes a federated database?

A federated database is characterized by the integration of multiple databases, allowing them to be queried as a single entity. This architecture enables users to access data residing in different databases across various locations without needing to physically consolidate all the data into one standalone database.

By leveraging a federated approach, organizations can maintain independent databases for various applications or departments while still providing a unified, coherent way for users to execute queries across these disparate sources. This enhances data accessibility and usability, promoting a more flexible and scalable data management environment.

The other choices do not accurately describe a federated database's nature. For instance, stating that only one database is accessible contradicts the fundamental premise of a federation, which focuses on linking multiple databases. Mentioning reliance on cloud storage suggests a limitation that does not apply because federated databases can be deployed on various infrastructures, including on-premises systems. Lastly, the assertion that it does not allow data sharing conflicts with the core feature of a federated database, which is designed precisely to facilitate shared access to multiple data sources.