FOR FREE MATERIALS
Functional Dependency Closer
.png)
Let a relation R (ABCD) and functional dependency FD’s {A → B, B → C}
.png)
.png)
In a function dependency, how many attribute/attributes possible on left-hand side.
.png)
Now we calculate each attribute closer and functional dependency:
1. Where we exclude A, B, and C and calculate FD for attribute ɸ
.png)
So, the number FD for attribute ɸ is 1.
2. Only A
.png)
Again at RHS, we get three options to make FDs.
.png)
.png)
.png)
.png)
.png)
.png)
.png)
.png)
.png)
.png)
.png)
.png)
.png)
.png)
.png)
.png)
.png)
.png)
.png)
.png)
.png)
.png)
.png)
.png)
.png)
.png)
.png)
.png)
.png)
.png)
.png)
.png)
Total number of FDs possbile
.png)
.png)
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}
.png)
.png)
.png)
.png)
.png)
.png)
Contributed by
