Multivalued dependency

In general, a multivalued dependency occurs when a relation R has attributes A, B, and C such that
A determines a set of values for B, A determines a set of values for C, and B and C are independent of each other.
We write this as
A –>> B and A –>> C
The formal definition of multivalued dependency is:
Definition. X –>> Y is a multivalued dependency if

If t1 and t2 are tuples such that t1.X = t2.X, then there are tuples t3 and t4 such that
1. t1.X = t3.X = t4.X 2. t1.Y = t3.Y and t2.Y = t4.Y 3. t1.Z = t4.Z and t2.Z = t3.Z
where Z = R – (X U Y)

9 thoughts on “Multivalued dependency”

Leave a Reply

Your email address will not be published. Required fields are marked *