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Functional Dependency Closer

Let a relation R (ABCD) and functional dependency FD’s {A → B, B → C}

In a function dependency, how many attribute/attributes possible on left-hand side.

Now we calculate each attribute closer and functional dependency:

1. Where we exclude A, B, and C and calculate FD for attribute ɸ

So, the number FD for attribute ɸ is 1.

2. Only A

Again at RHS, we get three options to make FDs.

Total number of FDs possbile

Question:

A relation R(A, B) and Functional Dependencies F = {A → B, B → A}.  How many Functional Dependencies are possible?

Solution:

Relation R(A, B) and given F ={A → B, B → A}