Consider the following two sets of functional dependencies: F = {A-->C, AC-->D,
ID: 3641580 • Letter: C
Question
Consider the following two sets of functional dependencies:F = {A-->C, AC-->D, E-->AD, E-->H}
and
G= { A-->CD, E-->AH} check weather they are equivalent ?
Explanation / Answer
consider the set F. fd AC-> D has left extraneous attribute(D) because of A->C,so it can be written as A->D. Now Combining A->C and A->D into one FD by using union rule of Armstrong axiom ,we get A->CD Similarly for E->AD, D is extraneous because of A->D so It becomes E->A ,using union rule of armstrong axiom we have E->AH Now Our Set F becomes { A->CD,E->AH} Which is similar to the set G.