What is the difference between the four standard transaction isolation levels (READ UNCOMMITTED, READ COMMITTED, REPEATABLE READ, SERIALIZABLE)?
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Incorrect.
The correct answer is B) They progressively reduce concurrency anomalies (dirty reads, non-repeatable reads, phantom reads) at the cost of reduced concurrency, with SERIALIZABLE providing the strongest guarantees and READ UNCOMMITTED the weakest
Correct Answer
They progressively reduce concurrency anomalies (dirty reads, non-repeatable reads, phantom reads) at the cost of reduced concurrency, with SERIALIZABLE providing the strongest guarantees and READ UNCOMMITTED the weakest
Each isolation level addresses progressively more concurrency anomalies: READ UNCOMMITTED allows dirty reads, READ COMMITTED prevents them but allows non-repeatable reads, REPEATABLE READ prevents those but allows phantoms, and SERIALIZABLE prevents all three at the cost of throughput.