GATE 2023 Databases Rank Booster Quiz 42

An account A has amount Rs 500 and another account B has amount Rs 200. A transaction occurs between them and after the transaction, the amount in A becomes Rs 300 and the amount in B becomes Rs 400. Which property of transaction is proved in this scenario?

Non-serial schedules are not always?

Consider the following schedule:

S: r₁(A), r₂(A), r₁(A), commit₁, w₃(A), commit₂, r₃(A), commit₃

Which of the following is true?

Consider a simple check pointing protocol and the following set of operations in the log.
(Start, T₄); (Start, T₁); (Write, T₁, a, 2, 3); (Write, T₄, b, 1, 2) (commit, T₁); (Start, T₃) (check point); (Write, T₃, C, 4, 7) (commit, T₄)
If crash happens now and the system tries to recover using both undo and redo operations, what are the contents of the undo list and redo list

Consider a schedule

S1. R1(x)W2(x)W1(x)W1(x) abort2 commit1

Given schedule is

Consider the following transaction involving two bank accounts x and y:

Read (x);

X = x – 50

Write (x);

Read (y);

y = y + 50;

write (y);

Which of the following constraints fail if transaction is fail just after write (x); operation?