Question 147
Comprehension:
Answer question (146-150) based on the problem statement given below:
An organization needs to maintain database having five attributes A, B, C, D, E.
These attributes are functionally dependent on each other for which functionally dependency set F is given as :
F : { A → BC, D → E, BC → D, A → D }.
Consider a universal relation R(A, B, C, D, E) with functional dependency set F.
Also all attributes are simple and take atomic values only.
Identify primary key of table R with functional dependency set F
Answer : 3. A Answer question (146-150) based on the problem statement given below:
An organization needs to maintain database having five attributes A, B, C, D, E.
These attributes are functionally dependent on each other for which functionally dependency set F is given as :
F : { A → BC, D → E, BC → D, A → D }.
Consider a universal relation R(A, B, C, D, E) with functional dependency set F.
Also all attributes are simple and take atomic values only.
Identify primary key of table R with functional dependency set F
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Since "A" is not in RHS of any FD
So, "A" is the key of relation R.
Now to see whether "A" is the primary key or not of relation “R”.
lets find closure of "A".
A+ = { A, B, C, D, E }.
Hence A is the primary key of relation R
So, option 3 is correct answer