CIL Part B

Question

Consider the following relation schema R and S along with their tuple sets.

R(A, B) = {   

                      <a1, b1 >, <a2, b1>, <a3, b1>,

                      <a4, b1>, <a1, b2>, <a3, b2>,

                      <a2, b3>, <a3, b3>, <a4, b3>,

                      <a1, b4>, <a2, b4>, <a3, b4>

                 }

S(A) = {a1, a2, a3}

What is the value of T ← R/S, where “/” represents the Relational Algebra “division” operation?

 

A. T(B) = {b1, b2, b4}

B. T(B) = {b1, b3, b4}

C. T(B) = {b1, b4)

D. T(B) = {b1, b3}

Answer 1

Answer is C

 

correct me if i am wrong