JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD MCA 2017 DISTRIBUTED DATABASES Previous Question Paper (August - 2017 - R13)

A distributed database system requires the following components: 1) Distributed Database Management System (DDBMS), which is the software that manages the distributed database and makes the distribution transparent to the user. 2) Computer Network, which provides the communication infrastructure connecting various sites. 3) Distributed Database, which is the collection of data logically related but physically distributed across multiple sites. 4) Sites/Nodes, which are the individual computing systems or locations that store fragments of the database and run local DBMS instances.

Parametric queries are pre-compiled queries that accept input parameters at runtime, allowing the same query structure to be reused with different data values, which improves performance and security. In contrast, nested queries (or subqueries) are queries embedded within another SQL query, where the inner query provides results to the outer query. While parametric queries focus on reusability and efficiency, nested queries focus on complex data retrieval by performing multi-step filtering or aggregation in a single statement.