What is Functional Dependency?

What is Functional Dependency?
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Answer :

A Functional dependency is denoted by X Y between two sets of attributes X and Y that are  subsets of R specifies a constraint on the possible tuple that can form a relation state r of R. The  constraint is for any two tuples t1 and t2 in r if t1[X] = t2[X] then they have t1[Y] = t2[Y]. This  means the value of X component of a tuple uniquely determines the value of component Y.
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Related questions

A B C is a set of attributes. The functional dependency is as follows AB -> B AC -> C C -> B a) is in 1NF b) is in 2NF c) is in 3NF d) is in BCNF

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Last Answer : a) is in 1NF

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