M E T U

DEPARTMENT OF COMPUTER ENGINEERING

 

C.Eng 352 - Database Management Systems

Prof. Dr. Adnan Yazıcı

Asst. Prof. Dr. Ahmet Coşar

Asst. Semra Doğandağ

Date given       : Dec 12, 2003

Date due         : Dec 22, 2003 (A302, before 17:00)

 

HOMEWORK NO 3

 

1. Given the following history

H = R1(x)R2(y)R3(x)W1(x)W3(y)W2(x)

 

a) Decide whether history H is view serializable or not. Show your work.

 

b) Decide whether history H is conflict-serializable or not. Show all conflicting operations.

 

2. Given the following history

 

R1(A)R4(A)R2(B)W1(A)W2(B)R4(B)R2(C)W2(C)R3(C)R4(C)R1(B)W3(C)W1(B)

 

a) Show whether this execution is conflict-serializable or not.

       

b) Show how a Strict Two-Phase Locking will execute this history. Draw the "Wait-for Graph" to indicate the transactions waiting for others and update it as necessary during execution.

 

c) Show how a Strict Timestamp Ordering will execute this history. Show all the details.