Distributed Database Question Bank with Answers 08

Question:

What different kinds of transparencies are handled by distributed, parallel, and federated databases?  

Answer:

Transparencies in distributed database:

• In a distributed database the location of data is designed manually by the DBA. The distribution is specified using conditions to the DDBMS that declaratively specify how to redistribute data in tables. Thus distributed databases do not have schema transparency, since the distributed schema is designed manually.

• In a distributed database queries and updates are specified without need to know the names of the tables in the individual parts of the database. This is called naming transparency.

• In a distributed database, the user need not know how to split a query or an update into different subqueries to the different parts of the database. This is called query and update transparency.

• In summary, distributed databases have query, update, and naming transparency, but no schema transparency. 

Transparencies in parallel database:

• Parallel databases have schema, query, update, and naming transparency. Parallel databases run on clusters, which enables the parallel DMBS to automatically place table fragments. 

Transparencies in federated database:

• Federated databases have query and naming transparency, but limited updating and no schema transparency. Updating the integrated underlying local databases has to be done locally. In the federated database only tables stored in the global conceptual schema can be updated. All participating database have separate schemas.

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List the transparencies shown by distributed database

List the transparencies supported by parallel database

List the transparencies shown by federated database

what are the transparencies supported and declined by distributed, parallel and federated database