Q: Finding the Closure of a functional dependency I am trying to find the Closure of a functional dependency for the following relation schema and I seem to be having some trouble.
Would anyone be able to provide any input?
X is the relational schema for the functional dependencies:
R = (A, B, C, D, E): 
{D→A, BA→C, C→E, E→DB}
Compute X+ (the closure of X)

A: X+ is a set of attributes that may be derived by applying Armstrong's principles. 
X in X+ refers to one or more attributes from our relation R.
So if X=A then
A+ = {A}
If X=C then
C+ = {A,B,C,D,E}
and if X=DA then
DA+ = {A,D}
and so on. I hope you got the idea.
