1. In the context of database transactions, what does "commit" refer to?
Explanation: In the context of database transactions, "commit" refers to making the transaction's changes permanent in the database.
Report for correction2. In the context of database transactions, what is a "deadlock"?
Explanation: A deadlock is a situation where two or more transactions are waiting for each other to release locks, causing a standstill.
Report for correction3. In the context of database transactions, what is a "non-repeatable read"?
Explanation: A non-repeatable read occurs when a transaction reads data that has been updated by another transaction before the first transaction is completed, leading to inconsistent results.
Report for correction4. In the context of database transactions, what is a "phantom read"?
Explanation: A phantom read occurs when a transaction reads data that has been deleted by another transaction before the first transaction is completed, leading to unexpected results.
Report for correction5. What does "ACID" stand for in the context of database transactions?
Explanation: ACID stands for Atomicity, Consistency, Isolation, and Durability, which are key properties of database transactions.
Report for correction Atomicity, Consistency, Isolation, Durability
Agile, Concurrency, Integrity, Durability
Availability, Consistency, Isolation, Decisiveness
All, Consistency, Inclusion, Dependency
6. What is a "dirty read" in the context of database transactions?
Explanation: A "dirty read" occurs when a transaction reads data that has not been committed by another transaction, potentially leading to inconsistent results.
Report for correction7. What is the primary purpose of the "COMMIT" statement in database transactions?
Explanation: The "COMMIT" statement in database transactions is used to commit a transaction and make its changes permanent in the database.
Report for correction8. What is the primary purpose of the "ROLLBACK TO SAVEPOINT" statement in database transactions?
Explanation: The "ROLLBACK TO SAVEPOINT" statement in database transactions is used to roll back a transaction to a specific savepoint within the transaction, allowing for partial rollbacks.
Report for correction9. What is the primary purpose of the "ROLLBACK" statement in database transactions?
Explanation: The "ROLLBACK" statement in database transactions is used to undo a transaction and revert any changes made during the transaction.
Report for correction10. What is the primary purpose of the "SAVEPOINT" statement in database transactions?
Explanation: The "SAVEPOINT" statement in database transactions is used to create a point within a transaction to which you can later roll back, allowing for partial rollbacks.
Report for correction11. Which isolation level allows for repeatable reads but still prevents dirty reads and non-repeatable reads?
Explanation: The Repeatable Read isolation level allows for repeatable reads, preventing dirty reads and non-repeatable reads.
Report for correction12. Which isolation level allows for the highest degree of isolation, preventing dirty reads, non-repeatable reads, and phantom reads?
Explanation: The Serializable isolation level provides the highest degree of isolation, preventing dirty reads, non-repeatable reads, and phantom reads, but it may lead to more contention.
Report for correction13. Which isolation level ensures that a transaction can read only committed data and prevents dirty reads?
Explanation: The Read Committed isolation level ensures that a transaction can read only committed data, preventing dirty reads.
Report for correction14. Which isolation level provides the highest level of data consistency but may lead to more contention and potential performance issues?
Explanation: The Serializable isolation level provides the highest level of data consistency but may lead to more contention and potential performance issues due to locking.
Report for correction15. Which level of isolation ensures that a transaction can read uncommitted data from other transactions?
Explanation: The Read Uncommitted isolation level allows a transaction to read uncommitted data from other transactions, offering the lowest level of isolation.
Report for correction16. Which property of ACID ensures that a transaction brings the database from one consistent state to another?
Explanation: Consistency ensures that a transaction brings the database from one consistent state to another, maintaining data integrity.
Report for correction17. Which property of ACID ensures that a transaction is either fully completed or fully rolled back in case of failure?
Explanation: Atomicity ensures that a transaction is either fully completed or fully rolled back in case of failure, maintaining data integrity.
Report for correction18. Which property of ACID ensures that a transaction is treated as a single, indivisible unit of work?
Explanation: Atomicity ensures that a transaction is treated as a single, indivisible unit of work, and it is either fully completed or fully rolled back in case of failure.
Report for correction19. Which property of ACID ensures that a transaction, once committed, cannot be undone or rolled back?
Explanation: Durability ensures that a transaction, once committed, cannot be undone or rolled back, and its changes are permanent.
Report for correction20. Which property of ACID ensures that concurrent transactions do not interfere with each other and appear to be executed serially?
Explanation: Isolation ensures that concurrent transactions do not interfere with each other and appear to be executed serially, preventing data inconsistencies.
Report for correction21. Which property of ACID ensures that once a transaction is committed, it is not lost even in the event of a system crash?
Explanation: Durability ensures that once a transaction is committed, it is not lost even in the event of a system crash or failure.
Report for correction22. Which property of ACID ensures that once a transaction is committed, its changes are permanent, even in the event of a system failure?
Explanation: Durability ensures that once a transaction is committed, its changes are permanent and survive system failures.
Report for correction23. Which property of ACID ensures that transactions are executed in a specific order, as they are received by the database?
Explanation: Durability ensures that transactions are executed in a specific order, as they are received by the database, to maintain data integrity.
Report for correction24. Which SQL statement is used to explicitly roll back a transaction in many relational databases?
Explanation: The "ROLLBACK" statement in many relational databases is used to explicitly roll back a transaction, undoing its changes.
Report for correction25. Which SQL statement is used to explicitly start a transaction in many relational databases?
Explanation: In many relational databases, the SQL statements "BEGIN" or "START TRANSACTION" are used to explicitly start a transaction.
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