Distributed Database Question Bank with Answers 01

Distributed  and parallel database questions and answers for University exams

Question:

What is a distributed database? What is it not? If all sites use a DBMS from the same vendor, what do we call it?

Answer:

Distributed Database System (DDBS)

A DDBS is made of several sites, each with a DBMS. Each site has one or more users so that each site can access data from any other site: each site can generate queries and acts a provider of data for other sites. A desirable feature is that each site maintains local autonomy without any reliance on a central site. So site A should be able to complete a database operation (assuming it has the necessary data) even if site B is down. 

What is not a DDBS?

A distributed database is NOT just a loose collection of database files that are spread at different locations and accessed from a specific DBMS.

Homogeneous DDBS

When all sites use a DBMS from the same vendor it is a homogeneous DDBS.  That means, all sites have identical database management system software, are aware of one another, and agree to cooperate in processing users’ requests

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