Database Management

Question

For R=(,B,C,D,E,F,G,H,I,J) and functional dependencies
H,D->A
D->E,F,G
H,D,B->C,J
H->I,J
A->BC
What will be all the candidate keys?
(I am getting DH as the candidate key)

Answer 1

Yes, you are getting the correct answer:
DH -> A,B,C,D,E,F,G,H,I,J

Thus, the relation is in the Second Normal form, because NOT-key attributes are dependent on other NOT-key attributes.

P.S. You have forgotten the A in the brackets ;)

Answer 2

But the relation should be in First Normal Form because H->I,J
and for 2NF,subset of the candidate key should not be determining non-prime attributes.

Answer 3

You are right about the second normal form.
And I'm sorry, but I only know until the 3.normal form.
Can't help you with Boyce-Codd.

Answer 4

Panayot Zhaltov please check once whether I am correct or not.
And also how to convert the relation to BCNF