Problems occurs if we don’t implement proper locking strategy
A. Dirty reads
B. Phantom reads
C. Lost updates
D. Unrepeatable reads
Answer:A
Problems occurs if we don’t implement proper locking strategy
A. Dirty reads B. Phantom reads C. Lost updates D. Unrepeatable reads
Explanation: In a concurrent execution of these transactions, it is intuitively clear that they conflict, but this is a conflict not captured by our simple model. This situation is referred to as the phantom phenomenon, because a conflict may exist on “phantom” data. 6. Which of the following fixed database roles can add or remove user IDs?