any relation which is in 3nf but not in bcnf?
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First you need to learn superkeys, candidate keys, and primary attributes.
However, this rule of thumb helps:
A 3NF table that does not have multiple overlapping candidate keys is guaranteed to be in BCNF.
In other words, if the candidate keys in a 3NF relation are
all atomic, ornon-atomic but non-overlapping,
it is guaranteed that the relation is in BCNF.
The simplest relation which violates BCNF but meets 3NF has the following functional dependencies:
A,B -> C C -> B
In this case, candidate keys are (A,B)and (A,C).
It meets 3NF because
the right-hand-side of all functional dependencies is a primary attribute.
It violates BCNF because
C -> B, but the left-hand-side is not a superkey.
HOPE IT HELPS PLEASE MARK AS THE BRAINLIEST ;)
However, this rule of thumb helps:
A 3NF table that does not have multiple overlapping candidate keys is guaranteed to be in BCNF.
In other words, if the candidate keys in a 3NF relation are
all atomic, ornon-atomic but non-overlapping,
it is guaranteed that the relation is in BCNF.
The simplest relation which violates BCNF but meets 3NF has the following functional dependencies:
A,B -> C C -> B
In this case, candidate keys are (A,B)and (A,C).
It meets 3NF because
the right-hand-side of all functional dependencies is a primary attribute.
It violates BCNF because
C -> B, but the left-hand-side is not a superkey.
HOPE IT HELPS PLEASE MARK AS THE BRAINLIEST ;)
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