Which of the following statements is/are True regarding some advantages that…
2016
Which of the following statements is/are True regarding some advantages that an object oriented DBMS (OODBMS) offers over a relational database ?
I. An OODBMS avoids the “impedance mismatch” problem.
II. An OODBMS avoids the “phantom” problem.
III. An OODBMS provides higher performance concurrency control than most relational databases.
IV. An OODBMS provides faster access to individual data objects once they have been read from disk.
- A.
II and III only
- B.
I and IV only
- C.
I, II, and III only
- D.
I, III and IV only
Attempted by 107 students.
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Correct answer: B
Answer: Statements I and IV are true; Statements II and III are false.
Statement I — An object-oriented DBMS avoids the “impedance mismatch” problem: True. Object databases map programming-language objects directly to stored objects, reducing the need for object-relational mapping and the resulting impedance mismatch.
Statement II — An object-oriented DBMS avoids the “phantom” problem: False. The phantom problem is a concurrency anomaly related to transaction isolation and range queries; it is addressed by transaction and locking protocols rather than by object orientation alone.
Statement III — An object-oriented DBMS provides higher performance concurrency control than most relational databases: False. Concurrency control performance depends on specific implementation and optimizations; relational DBMSs often have highly optimized, mature concurrency mechanisms, so this is not an inherent advantage of object databases.
Statement IV — An object-oriented DBMS provides faster access to individual data objects once they have been read from disk: True. Object databases use object identifiers and pointer-based navigation and can cache object references, which often allows faster direct access to individual objects and avoids expensive relational joins.
Conclusion: The correct selection includes statements I and IV only.