Which statement best defines a distributed database in terms of logical unity and physical distribution across networked locations?
-
AA single logical database that is spread to multiple locations and is interconnected by a network
-
BA loose collection of file that is spread to multiple locations and is interconnected by a network
-
CA single logical database that is limited to one location.
-
DA loose collection of file that is limited to one location.
Answer
Correct Answer: A single logical database that is spread to multiple locations and is interconnected by a network
Explanation
Introduction / Context:Distributed databases present a unified logical view of data even when the data is physically partitioned or replicated across multiple sites. This definition distinguishes them from simple file sharing or isolated databases.
Given Data / Assumptions:
- Multiple sites connected via a network.
- Transparency goals (location, fragmentation, replication) typical in distributed DBMS.
- Unified schema or global catalog provides the single logical view.
Concept / Approach:A distributed database is one logical database that spans sites. Users query it as if it were centralized; the DBMS handles routing, fragmentation, and replication behind the scenes.
Step-by-Step Solution:
Check for “single logical” and “multiple locations.”Reject definitions that imply mere files or single-site scope.Choose the option combining logical unity with physical distribution.Verification / Alternative check:Classic distributed DB definitions (for example, Ceri & Pelagatti) emphasize logical integration with physical distribution.
Why Other Options Are Wrong:
- B and D: describe loose file collections, not DBMS-managed databases.
- C: describes a centralized database.
Common Pitfalls:Equating “federated” file access or ETL copies with a distributed DBMS; the latter supplies a global schema and query processing.
Final Answer:A single logical database that is spread to multiple locations and is interconnected by a network