Practice Library
All MCQs
Browse exam-wise, subject-wise, and country-wise MCQs with explanations.
Choose an option to check your answer.
A.
the DBMS manages pages between disk and memory to reduce I/O cost
B.
the DBMS stores all data permanently in CPU registers
C.
the DBMS disables transactions
D.
the DBMS removes indexes from all tables
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Correct Answer: A. the DBMS manages pages between disk and memory to reduce I/O cost
Explanation:
buffer management is used in Advanced DBMS because the DBMS manages pages between disk and memory to reduce I/O cost.
Choose an option to check your answer.
A.
an operation that combines rows from related tables based on a condition
B.
a function used only in PL/SQL loops
C.
an operation that deletes indexes after commit
D.
a file backup operation
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Correct Answer: A. an operation that combines rows from related tables based on a condition
Explanation:
This statement is correct because join operation means that an operation that combines rows from related tables based on a condition.
Choose an option to check your answer.
A.
a method that reads only index leaf entries
B.
a data access method that reads all rows of a table
C.
a method that blocks all transactions
D.
a method that replicates data across sites
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Correct Answer: B. a data access method that reads all rows of a table
Explanation:
The correct answer explains full table scan in the context of Query Processing.
Choose an option to check your answer.
A.
a lock mode for dirty reads
B.
a hardware protocol for disk mirroring
C.
Microsoft SQL Server’s extension of SQL for procedural programming and administration
D.
a document-oriented NoSQL model only
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Correct Answer: C. Microsoft SQL Server’s extension of SQL for procedural programming and administration
Explanation:
T-SQL is used in Advanced DBMS because Microsoft SQL Server’s extension of SQL for procedural programming and administration.
Choose an option to check your answer.
A.
a graph used to encrypt user passwords
B.
a graph used to test conflict serializability by checking cycles
C.
a MongoDB replication topology only
D.
a diagram used only for ER modeling
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Correct Answer: B. a graph used to test conflict serializability by checking cycles
Explanation:
precedence graph is used in Advanced DBMS because a graph used to test conflict serializability by checking cycles.
Choose an option to check your answer.
A.
all transactions execute without locks
B.
a transaction has a growing phase for acquiring locks and a shrinking phase for releasing locks
C.
locks are acquired and released randomly
D.
locks are used only for backup files
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Correct Answer: B. a transaction has a growing phase for acquiring locks and a shrinking phase for releasing locks
Explanation:
This statement is correct because two-phase locking means that a transaction has a growing phase for acquiring locks and a shrinking phase for releasing locks.
Choose an option to check your answer.
A.
the system checks for cycles in a wait-for graph and resolves them
B.
the system removes all constraints
C.
the system stores all logs on paper
D.
the system prevents all reads from happening
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Correct Answer: A. the system checks for cycles in a wait-for graph and resolves them
Explanation:
The correct answer explains deadlock detection in the context of Concurrency Control.
Choose an option to check your answer.
A.
creates a secondary index
B.
blocks all future transactions
C.
reapplies committed updates during recovery to ensure durability
D.
removes every committed transaction
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Correct Answer: C. reapplies committed updates during recovery to ensure durability
Explanation:
redo operation is used in Advanced DBMS because reapplies committed updates during recovery to ensure durability.
Choose an option to check your answer.
A.
a graph used to encrypt user passwords
B.
a graph used to test conflict serializability by checking cycles
C.
a MongoDB replication topology only
D.
a diagram used only for ER modeling
Show Answer
Correct Answer: B. a graph used to test conflict serializability by checking cycles
Explanation:
This statement is correct because precedence graph means that a graph used to test conflict serializability by checking cycles.
Choose an option to check your answer.
A.
shared locks are never used
B.
deadlocks cannot occur under any condition
C.
all locks are released before the first write
D.
exclusive locks are held until the transaction commits or aborts
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Correct Answer: D. exclusive locks are held until the transaction commits or aborts
Explanation:
The correct answer explains strict two-phase locking in the context of Concurrency Control.
Choose an option to check your answer.
A.
the system prevents all reads from happening
B.
the system checks for cycles in a wait-for graph and resolves them
C.
the system stores all logs on paper
D.
the system removes all constraints
Show Answer
Correct Answer: B. the system checks for cycles in a wait-for graph and resolves them
Explanation:
deadlock detection is used in Advanced DBMS because the system checks for cycles in a wait-for graph and resolves them.
Choose an option to check your answer.
A.
reapplies committed updates during recovery to ensure durability
B.
blocks all future transactions
C.
removes every committed transaction
D.
creates a secondary index
Show Answer
Correct Answer: A. reapplies committed updates during recovery to ensure durability
Explanation:
This statement is correct because redo operation means that reapplies committed updates during recovery to ensure durability.
