Equivalence of Functional Dependencies
For understanding the equivalence of Functional Dependencies Sets (FD sets), the basic idea about Attribute Closuresis given in this article Given a Relation with different FD sets for that relation, we have to find out whether one FD set is a subset of another or both are equal. How do find the relationship between two FD sets? Let FD1 and FD2 be two FD sets for a relation R.
- If all FDs of FD1 can be derived from FDs present in FD2, we can say that FD2 ⊃ FD1.
- If all FDs of FD2 can be derived from FDs present in FD1, we can say that FD1 ⊃ FD2.
- If 1 and 2 both are true, FD1=FD2.
All these three cases can be shown using the Venn diagram: