Transaction Management in Database Systems: Master the ACID Properties

Question 1

Which ACID property guarantees that transactions do not modify data that is being modified by other concurrent transactions?

Accepted Answer

Isolation

Answer

Atomicity

Answer

Consistency

Answer

Durability

Question 2

Which type of concurrency control mechanism relies on the assumption that conflicts are infrequent and uses optimistic locking to handle conflicts?

Accepted Answer

Optimistic concurrency control

Answer

Pessimistic concurrency control

Answer

Timestamp ordering

Answer

Lock-based concurrency control

Question 3

Which recovery technique uses a mechanism that periodically saves a snapshot of the database's state to enable transaction rollback in the event of a system failure?

Accepted Answer

Checkpointing

Answer

Write-ahead logging

Answer

Shadow paging

Answer

Transaction rollback

Question 4

What is the primary function of a redo log in transaction management?

Accepted Answer

To record all updates made by committed transactions

Answer

To restore lost data in case of a system failure

Answer

To enforce data integrity constraints

Answer

To improve query performance

Question 5

Which of the following is a potential drawback of using optimistic concurrency control?

Accepted Answer

Increased data conflicts

Answer

Reduced concurrency

Answer

Decreased performance for read-only transactions

Answer

Increased system overhead

Question 6

What is the primary objective of a serializable transaction?

Accepted Answer

To ensure that the execution of a transaction appears isolated from other concurrent transactions

Answer

To guarantee that the database is always in a consistent state

Answer

To maximize concurrency among multiple transactions

Answer

To prevent deadlocks

Question 7

What is the fundamental difference between logical and physical logs in transaction management?

Accepted Answer

Logical logs record changes made to data, while physical logs record changes made to disk blocks

Answer

Physical logs record changes made to data, while logical logs record changes made to disk blocks

Answer

Logical logs are used for recovery, while physical logs are used for auditing

Answer

Physical logs are used for recovery, while logical logs are used for auditing

Question 8

Which concurrency control mechanism ensures that transactions execute one at a time in a serial order?

Accepted Answer

Two-phase locking

Answer

Locking

Answer

Timestamping

Answer

Optimistic concurrency control

Question 9

What is the primary purpose of a recovery log in a database system?

Accepted Answer

To provide a backup in case of system failure

Answer

To store all database changes permanently

Answer

To record all committed transactions

Answer

To optimize query performance

Question 10

Which of the following is an example of a deadlock scenario in a database system?

Accepted Answer

Two transactions waiting for each other to release locks

Answer

A transaction waiting for a lock held by another transaction

Answer

Multiple transactions trying to access the same data item concurrently

Answer

A transaction waiting for a resource that is not available

Question 11

What is the key difference between hard recovery and soft recovery in a database system?

Accepted Answer

Hard recovery restores the database to a known state before the failure, while soft recovery restores the database to the most recent committed state

Answer

Soft recovery restores the database to a known state before the failure, while hard recovery restores the database to the most recent committed state

Answer

Hard recovery is faster than soft recovery

Answer

Soft recovery is more reliable than hard recovery

Question 12

What is the primary responsibility of a transaction coordinator in a distributed database system?

Accepted Answer

Managing the execution of transactions across multiple sites

Answer

Ensuring that transactions are atomic and isolated

Answer

Providing deadlock detection and resolution

Answer

Optimizing query performance

Question 13

Which characteristic ensures that a transaction is an indivisible unit of work that must either succeed or fail atomically?

Accepted Answer

Atomicity

Answer

Consistency

Answer

Isolation

Answer

Durability

Question 14

What is the primary responsibility of the lock manager in a database management system?

Accepted Answer

Preventing concurrent transactions from accessing the same data simultaneously

Answer

Ensuring that all transactions execute in a strict sequential order

Answer

Recovering data in the event of a system failure

Answer

Maintaining the integrity of the database structure

Question 15

What is the key distinction between a savepoint and a checkpoint in database transactions?

Accepted Answer

A savepoint is a temporary rollback point, whereas a checkpoint is a permanent one.

Answer

A checkpoint is a temporary rollback point, whereas a savepoint is a permanent one.

Answer

Savepoints and checkpoints serve identical purposes and can be used interchangeably.

Answer

Checkpoints are used for database recovery, while savepoints are exclusively for concurrency control.

Question 16

What is the primary objective of the two-phase commit (2PC) protocol?

Accepted Answer

Ensuring that all participants in a distributed transaction agree to either commit or abort the transaction collectively

Answer

Preventing deadlocks in multi-user database environments

Answer

Recovering data in the event of a system failure

Answer

Maintaining the integrity of the database structure

Question 17

What is the purpose of a database shadow page?

Accepted Answer

To store a duplicate copy of a data page that can be used for recovery in the event of a failure

Answer

To reduce the number of disk input/output operations by caching frequently accessed data

Answer

To enhance query performance by storing precomputed results

Answer

To preserve the integrity of the database structure

Question 18

What is the primary purpose of a lock manager in a database system?

Accepted Answer

To grant and revoke locks to transactions to ensure data consistency

Answer

To manage user authorization and authentication

Answer

To maintain data integrity

Answer

To optimize query response time

Question 19

Which of the following recovery techniques involves restoring a database to its state before a failure occurred?

Accepted Answer

Backward recovery

Answer

Forward recovery

Answer

Differential recovery

Answer

Incremental recovery

Question 20

What is the primary goal of transaction isolation?

Accepted Answer

To ensure that concurrent transactions do not interfere with each other

Answer

To prevent data corruption

Answer

To improve query performance

Answer

To reduce the risk of deadlocks

Question 21

Which of the following is a potential benefit of pessimistic concurrency control?

Accepted Answer

Improved data consistency

Answer

Reduced probability of deadlocks

Answer

Increased performance for short transactions

Answer

Simplified implementation

Question 22

What is the purpose of a commit log in a database system?

Accepted Answer

To record all database modifications made by transactions

Answer

To store the current state of the database

Answer

To manage user accounts and permissions

Answer

To optimize query performance

Question 23

What is the purpose of a transaction timestamp?

Accepted Answer

To determine the order of transactions

Answer

To identify the transaction

Answer

To detect and resolve deadlocks

Answer

To maintain data integrity

Question 24

What is the primary goal of database normalization?

Accepted Answer

To reduce data redundancy

Answer

To improve data consistency

Answer

To enhance query performance

Answer

To facilitate data analysis

Question 25

Which of the following is **not** a property of ACID transactions?

Accepted Answer

Isolation

Answer

Atomicity

Answer

Consistency

Answer

Durability

Question 26

What is the primary purpose of a **log** in transaction management?

Accepted Answer

To record all actions performed by transactions.

Answer

To store temporary data during transaction execution.

Answer

To ensure that transactions are executed in the correct order.

Answer

To prevent data loss in case of system failures.

Question 27

Which of the following recovery techniques is used to restore a database to a consistent state after a system failure by applying **only** the changes made since the last backup?

Accepted Answer

Incremental recovery

Answer

Differential recovery

Answer

Full recovery

Answer

Partial recovery

Question 28

Which of the following is **not** a type of concurrency conflict?

Accepted Answer

Read-read

Answer

Read-write

Answer

Write-read

Answer

Write-write

Question 29

In timestamp-based concurrency control, what is the primary function of timestamps?

Accepted Answer

Uniquely identifying each transaction

Answer

Tracking the duration of each transaction

Answer

Detecting and resolving deadlocks

Question 30

In database systems, which approach is ineffective for resolving deadlocks?

Accepted Answer

Ignoring the issue

Answer

Timestamp ordering

Answer

Wait-die protocol

Answer

Wound-wait protocol

Question 31

Which statement accurately describes the impact of transaction isolation levels on database performance and data integrity?

Accepted Answer

Lower isolation levels prioritize performance but may jeopardize data integrity

Answer

Higher isolation levels enhance performance but weaken data integrity

Answer

Isolation levels have no effect on performance or data integrity

Question 32

Which of the following properties is NOT a part of the ACID model?

Accepted Answer

Parallelism

Answer

Atomicity

Answer

Consistency

Answer

Isolation

Question 33

What is the primary function of a lock manager in a database system?

Accepted Answer

To prevent concurrent transactions from accessing the same data simultaneously.

Answer

To record the changes made by each transaction.

Answer

To ensure that all transactions are executed in a consistent order.

Answer

To recover data in case of a system failure.

Question 34

What is the primary objective of a commit protocol?

Accepted Answer

To ensure that all changes made by a transaction are permanently recorded in the database.

Answer

To prevent concurrent transactions from accessing the same data simultaneously.

Answer

To recover data in case of a system failure.

Answer

To improve the performance of transaction processing.

Question 35

In transaction management systems, particularly in environments prone to concurrent access, which method is commonly used to detect deadlocks?

Accepted Answer

Wait-for graph

Answer

Timestamp ordering

Answer

Wound-wait algorithm

Answer

Optimistic concurrency control

Question 36

Which of the following is NOT an ACID property of transactions?

Accepted Answer

Redundancy

Answer

Atomicity

Answer

Consistency

Answer

Isolation

Question 37

What is the primary purpose of using locks in a database system?

Accepted Answer

To prevent concurrent access to data and maintain data integrity

Answer

To ensure that data is consistent across all transactions

Answer

To recover data in the event of a failure

Answer

To optimize query performance and reduce latency

Question 38

Which recovery technique is commonly used to restore the database to a consistent state after a system failure?

Accepted Answer

Write-ahead logging

Answer

Shadow paging

Answer

RAID

Answer

Checkpointing

Question 39

What is the key difference between a hard lock and a soft lock in a database system?

Accepted Answer

A hard lock prevents all access to data, while a soft lock allows read-only access.

Answer

A soft lock prevents all access to data, while a hard lock allows read-only access.

Answer

There is no difference between a hard lock and a soft lock.

Answer

A hard lock is used for short-term transactions, while a soft lock is used for long-term transactions.

Question 40

Which of the following is a primary benefit of using transactions in a database system?

Accepted Answer

Ensuring data integrity and consistency

Answer

Improving concurrency and reducing data conflicts

Answer

Simplifying database design and reducing complexity

Answer

Increasing database performance and reducing response times

Question 41

What is the main purpose of using a timestamp in a concurrency control mechanism?

Accepted Answer

To order transactions chronologically and prevent conflicts

Answer

To prevent deadlocks and ensure fairness

Answer

To ensure data consistency and recoverability

Answer

To optimize query performance and reduce latency

Question 42

What is the primary purpose of using distributed transactions in a database system?

Accepted Answer

To manage transactions across multiple databases and ensure data consistency

Answer

To improve the overall performance and scalability of the database system

Answer

To simplify the design and implementation of database applications

Answer

To increase the security and reliability of the database system

Question 43

What is the primary role of a lock manager in a database system?

Accepted Answer

To coordinate and control concurrent access to shared database resources, preventing conflicts and ensuring data integrity.

Answer

To store and manage transaction logs for recovery purposes.

Answer

To identify and resolve deadlocks that may occur during concurrent transactions.

Question 44

What is the main function of a transaction log in a database system?

Accepted Answer

To provide a sequential record of all changes made to the database during a transaction, enabling recovery and ensuring data integrity in case of failures.

Answer

To serve as a backup copy of the database, allowing restoration in case of data loss.

Answer

To capture the complete state of the database at specific points in time, facilitating historical analysis.

Question 45

Which advantage is inherent to optimistic concurrency control in database systems?

Accepted Answer

Elimination of locking mechanisms, potentially enhancing system performance by reducing lock contention.

Answer

Simplified implementation and management compared to other concurrency control methods.

Answer

Guaranteed prevention of conflicts between concurrent transactions.

Question 46

What is deadlock in the context of database transactions?

Accepted Answer

A state where two or more transactions are indefinitely waiting for each other to release acquired locks, resulting in a system impasse.

Answer

An error that occurs when a transaction is unable to commit successfully.

Answer

A condition where a transaction has obtained all necessary locks and can proceed without conflicts.

Question 47

What is a key disadvantage of using pessimistic concurrency control in database systems?

Accepted Answer

Increased potential for lock contention, which can lead to performance degradation and reduced system throughput.

Answer

Unsuitability for certain database workloads and applications.

Answer

Complexity in implementation and management compared to optimistic concurrency control.

Question 48

What is the fundamental difference between a hard commit and a soft commit in a database system?

Accepted Answer

A hard commit ensures permanent storage of transaction changes to non-volatile memory, while a soft commit does not guarantee immediate persistence, potentially leaving data vulnerable to loss in case of system failures.

Answer

A hard commit is a faster operation compared to a soft commit.

Question 49

What is a primary benefit of utilizing a database system that supports transactions?

Accepted Answer

Preservation of database consistency and integrity, ensuring that data remains accurate and reliable despite concurrent access and modifications.

Answer

Enabling simultaneous access to the database by multiple users without data conflicts.

Answer

Enhancement of data retrieval performance through optimized indexing and query processing.

Question 50

What is the primary purpose of transaction isolation levels in a database system?

Accepted Answer

To define the degree of visibility of uncommitted changes made by one transaction to other concurrent transactions, ensuring data consistency and preventing anomalies.

Answer

To eliminate the possibility of deadlocks occurring during concurrent transactions.