For a database relation R(A, B, C, D) where the domains of A, B, C and D include only atomic values, only the following functional dependencies and those that can be inferred from them are :

A → C

B → D

The relation R is in _______.

**(A)** First normal form but not in second normal form.

**(B)** Both in first normal form as well as in second normal form.

**(C)** Second normal form but not in third normal form.

**(D)** Both in second normal form as well as in third normal form.

**Answer:** **(A)** **Explanation:** A relation is in first normal form if every attribute in that relation is single valued attribute. It is in 1NF.

{A,B} are prime attribtes and {C,D} are non-prime attribute.

A^{+} = {A,C}

B^{+} = {B,D}

{A,B}^{+} = {A,B,C,D} so AB is the key.

But A^{+} = {A,C}

B^{+} = {B,D} makes it partial dependency.

So, this relation is not in 2NF.

So, option (A) is correct.

Quiz of this Question

Data Structures and Algorithms – Self Paced Course

View Details