For the following relation schema and sets of FD\'s R(a,b,c,d) with Fd\'s a->b,

Question

For the following relation schema and sets of FD's


R(a,b,c,d) with Fd's a->b, b->c , c->d , and d->a
A) indicate all the BCNF violationd. Do not forget to consider Fd's that are not in the given set, but follow from them. However it is necessary to give violations that have more than one attribute on the right side.
B) Decompse the relations, as necessary , into collections of relations that are in BCNF
For the following relation schema and sets of FD's


R(a,b,c,d) with Fd's a->b, b->c , c->d , and d->a
A) indicate all the BCNF violationd. Do not forget to consider Fd's that are not in the given set, but follow from them. However it is necessary to give violations that have more than one attribute on the right side.
B) Decompse the relations, as necessary , into collections of relations that are in BCNF
For the following relation schema and sets of FD's


R(a,b,c,d) with Fd's a->b, b->c , c->d , and d->a
A) indicate all the BCNF violationd. Do not forget to consider Fd's that are not in the given set, but follow from them. However it is necessary to give violations that have more than one attribute on the right side.
B) Decompse the relations, as necessary , into collections of relations that are in BCNF

Explanation / Answer

1.   A->ABCD, B->ABCD, C->ABCD, D->ABCD
Thus, candidate keys are A,B,C,D
Since all are candidate keys, there is NO BCNF Nor 3NF violations. No decomposition necessary.

2.   AB->ABCD.
Thus, AB is candidate key.
B->C, B-D both violate BCNF

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