Database Management System MCQs with Answers
Practice important Database Management System MCQs with answers and explanations.
Chapter: 42
Q681:
What is the primary function of a waits-for graph in deadlock detection?
A. To track the progress of transactions
B. To identify deadlock cycles
C. To record the number of transactions
D. To monitor transaction throughput
Correct Answer:
B
Chapter: 42
Q682:
Fill in the blank: In a DBMS, a transaction is seen as a series of _____, which can include reads and writes of database objects.
A. Operations
B. Transactions
C. Commands
D. Actions
Correct Answer:
D
Chapter: 42
Q683:
Fill in the blank: A schedule that guarantees the effect of executing transactions serially is known as a _____ schedule.
A. Serializable
B. Concurrent
C. Parallel
D. Transactional
Correct Answer:
A
Chapter: 43
Q684:
What does the Incremental Log with Deferred Updates approach involve?
A. Immediate updates to database buffers
B. Log file entries for write operations are immediate
C. Deferred updates until commit is executed
D. Immediate log file entries for all operations
Correct Answer:
C
Chapter: 43
Q685:
What is a checkpoint in the context of database recovery?
A. A record of transactions to be redone
B. A record marking the start of a transaction
C. A milestone that guarantees prior commits are reflected in the database
D. A point where database buffers are refreshed
Correct Answer:
A
Chapter: 43
Q686:
What type of log file entry is used in the Incremental Log with Immediate Updates approach?
A. <Tn, X, 33>
B. <Tn, X, old_val, new_val>
C. <Tn, commit>
D. <Tn, begin>
Correct Answer:
B
Chapter: 43
Q687:
When a crash occurs, which transactions are redone according to the deferred update approach?
A. Transactions with begin and commit entries
B. Transactions with begin and abort entries
C. Transactions with only begin entries
D. All transactions regardless of their status
Correct Answer:
A
Chapter: 43
Q688:
In the event of a system crash, how does the recovery manager handle transactions with only a begin entry and no commit or abort?
A. The transactions are redone
B. The transactions are ignored
C. The transactions are committed
D. The transactions are canceled
Correct Answer:
B
Chapter: 43
Q689:
Fill in the blank: The deferred updates approach involves placing an entry in the log file only for a _______ operation.
A. read
B. write
C. delete
D. update
Correct Answer:
B
Chapter: 43
Q690:
What problem occurs when multiple transactions update the same object concurrently without proper control?
A. Lost Update Problem
B. Uncommitted Update Problem
C. Inconsistent Analysis Problem
D. Deadlock Problem
Correct Answer:
A
Chapter: 43
Q691:
How does the Recovery Manager handle transactions with a commit entry but with already applied changes during a crash?
A. The changes are redone
B. The changes are ignored
C. The changes are reversed
D. The changes are merged
Correct Answer:
A
Chapter: 43
Q692:
Which of the following is NOT a problem due to concurrent access?
A. Lost Update Problem
B. Uncommitted Update Problem
C. Inconsistent Analysis Problem
D. No Update Problem
Correct Answer:
D
Chapter: 43
Q693:
What should a log file entry look like in the Immediate Updates approach when a transaction is aborted?
A. <Tn, X, old_val, new_val>
B. <Tn, begin>
C. <Tn, commit>
D. <Tn, X, new_val>
Correct Answer:
A
Chapter: 43
Q694:
In the Lost Update Problem, what value is overwritten by the final write operation?
A. The value written by the first transaction
B. The initial value of the object
C. The value written by the second transaction
D. The final value of the object
Correct Answer:
B
Chapter: 43
Q695:
Fill in the blank: In the Incremental Log with Deferred Updates approach, log entries are made for _______ operations only.
A. read
B. write
C. commit
D. begin
Correct Answer:
B
Chapter: 43
Q696:
How are transactions with a begin and abort entry treated during recovery?
A. They are redone
B. They are ignored
C. They are committed
D. They are reversed
Correct Answer:
B
Chapter: 43
Q697:
Fill in the blank: The primary goal of concurrency control is to maintain the _______ of the database in the face of concurrent access.
A. security
B. consistency
C. integrity
D. availability
Correct Answer:
B
Chapter: 43
Q698:
What action is taken when a transaction with a begin entry and no commit or abort entry is detected during recovery?
A. It is redone
B. It is ignored
C. It is reversed
D. It is committed
Correct Answer:
B
Chapter: 43
Q699:
What is a key characteristic of the Immediate Updates approach compared to Deferred Updates?
A. Immediate update of database buffers
B. Deferred logging of write operations
C. Delayed database updates
D. Immediate log entries for all operations
Correct Answer:
A
Chapter: 44
Q700:
What problem occurs when a transaction updates an object and another transaction reads this updated value before the first transaction is aborted?
A. Uncommitted Update Problem
B. Inconsistent Analysis
C. Deadlock
D. Snapshot Isolation
Correct Answer:
A