GATE 1997 2.3 For a database relation R(a,b,c,d), whe

GATE 1997
2.3  For a database relation R(a,b,c,d), where the domains of a, b, c, d include only
atomic values, only the following functional dependencies and those that can be
inferred from them hold:
a -->c
b -->d
This relation is
(a) in first normal form but not in second normal form
(b) in second normal form but not in third normal form
(c) in third normal form
(d) None of the above
 

Ans:A

For finding normal form, we should first concentrate on finding key. If you find key of this relation, it is " ab" .Prime attribute { a,b} and non prime attribute {c,d}.

 The relation will be in 2NF if every Non Prime attribute is fully functional dependent on KEY.

Here {c,d } are not fully functionally dependent,rather they are partially dependent.

So this relation is in 1NF but not in 2NF.

Let me know if I am unclear.

2Comment
lonasarkarcs's picture
L S @lonasarkarcs 19 Oct 2014 11:11 am
vivek14's picture
Vivek Vikram Singh @vivek14 20 Oct 2014 10:40 pm

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