The questions can come in any order, so make sure you are selecting right option for all questions.
1.
Consider the following transactions T1, T2, and T3, with operations Read(X) and Write(X), where X is a data item:
T1: Read(X), Write(X)
T2: Write(X)
T3: Read(X), Write(X)
In the given scenario, which schedule is an example of an irrecoverable schedule?
(c) T2, T1, T3
2. What is a "conflict" in the context of conflict serializability?
(c) A situation where two transactions access the same data item, and at least one of them performs a write
3.
Consider the following transactions T4, T5, and T6, with operations Read(Y) and Write(Y), where Y is a data item:
T4: Write(Y)
T5: Read(Y), Write(Y)
T6: Read(Y), Write(Y)
In the given scenario, which schedule is an example of a recoverable schedule?
(a) T4, T5, T6
4.
Consider the following transactions T4, T5, and T6, with operations Read(Y) and Write(Y), where Y is a data item:
T4: Write(Y)
T5: Read(Y), Write(Y)
T6: Read(Y), Write(Y)
If transaction T5 fails after its Write(Y) operation, which of the following schedules ensures recoverability?
(a) T4, T5, T6
5. Which of the following is a characteristic of a non-serial schedule?
(b) Transactions are executed concurrently or interleaved
6. In the context of database schedules, what is a "serial schedule"?
(b) A schedule where transactions are executed sequentially, one after the other
7.
Consider the following transactions T1, T2, and T3, with operations Read(X) and Write(X), where X is a data item:
T1: Read(X), Write(X)
T2: Write(X)
T3: Read(X), Write(X)
If transaction T2 fails after its Write(X) operation, which of the following schedules ensures recoverability?
(b) T1, T3, T2
8. What does "serializability" in the context of database transactions refer to?
(b) Ensuring that the final result of concurrent transaction execution is equivalent to some serial execution
9.
Consider the following transactions T1, T2, and T3, with operations Read(X) and Write(X), where X is a data item:
T1: Read(X), Write(X)
T2: Write(X)
T3: Read(X), Write(X)
In the given scenario, which schedule is an example of a recoverable schedule?
(b) T1, T3, T2