Difference between canonical cover and minimal cover

Question

I know how to calculate a minimal cover-- ensure each functional dependency only has one attribute on the RHS, remove extraneous/redundant LHS attributes by calculating the closure of each, examining all FD's, seeing if any can be removed (again by calculating a closure).

Is 'canonical' cover just another word for the same thing?

Answer 1

A canonical cover is "allowed" to have more than one attribute on the right hand side. A minimal cover cannot. As an example, the canonical cover may be "A -> BC" where the minimal cover would be "A -> B, A -> C". That is the only difference.

Answer 2

These are the same.

The goal in calculating the canonical is to provide a minimum, in matters of redundancy.

Canonical