Assume the schedule S: W4(y) R1(x) R1(w) W1(w) W2(x) C2 W3(w) C3 W4(w) C4 W1(z) C1

Where Rn(x)/Wn(x) indicates transaction Tn reads/writes data item x, and Cn indicates Tn commits.

1.Show the precedence graph of S.

2.Prove S is correct, i.e., serializable.

3.Enumerate all serial schedules that are equivalent to S.