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DBMS Objective Questions and Answers - Set 3
This DBMS quiz contains carefully curated objective questions with correct answers and clear explanations. It is designed for computer science students, backend developers, and interview preparation, focusing on database design, SQL internals, transactions, indexing, and performance tuning. This is part 3 of the series.
Practice DBMS MCQs with Detailed Explanations
Answer at least 12 questions to submit and verify answers.
31 Which recovery technique uses shadow paging? High
Correct answer:
No-UNDO/REDO
Shadow paging avoids logging by maintaining shadow copies of pages.
32 Which join requires both inputs to be sorted? Medium
Correct answer:
Sort merge join
Sort merge join operates on sorted relations.
33 Which isolation level prevents phantom reads? High
Correct answer:
Serializable
Serializable isolation fully prevents phantom reads.
34 Which SQL constraint enforces domain integrity? Medium
Correct answer:
CHECK
CHECK enforces valid domain values.
35 Which dependency is required for lossless decomposition? High
Correct answer:
Functional dependency
Lossless decomposition relies on functional dependencies.
36 Which problem occurs in Read Committed isolation? Medium
Correct answer:
Non-repeatable read
Read Committed allows non-repeatable reads.
37 Which file organization is best for sequential access? Medium
Correct answer:
Sequential
Sequential organization is optimized for ordered access.
38 Which SQL feature improves performance of repeated queries? Medium
Correct answer:
Index
Indexes reduce search space and speed up query execution.
39 Which concurrency issue does strict 2PL avoid? High
Correct answer:
Cascading rollback
Strict 2PL prevents cascading rollback by holding locks until commit.
40 Which SQL statement permanently removes a table? Easy
Correct answer:
DROP
DROP removes the table structure and data permanently.
41 Which index supports equality search efficiently? Medium
Correct answer:
Hash index
Hash indexes are optimal for equality-based lookups.
42 Which transaction property ensures all-or-nothing execution? Medium
Correct answer:
Atomicity
Atomicity ensures complete execution or rollback.
43 Which join avoids sorting but requires memory? High
Correct answer:
Hash join
Hash join avoids sorting but relies on sufficient memory.
44 Which SQL keyword removes duplicate rows? Medium
Correct answer:
DISTINCT
DISTINCT eliminates duplicate rows from the result set.
45 Which database component manages metadata? Medium
Correct answer:
Data dictionary
The data dictionary stores metadata about database objects.