R(A, B, C, D, E)

All attributes contain only atomic values.

FD1: A ? BC

FD2: CD ? E

FD3: B ? D

FD4: A ? E

(a) Compute A+, the attribute closure of attribute A.

(b) List the candidate keys of R.

(c) Whats the highest normal form that R satisfies and why?

(d) If R is not already at least in 3NF, then normalize R into 3NF and show the resulting relation(s) and their candidate keys. Your decomposition should be both join-lossless and dependency-preserving. If R is already in 3NF, just list the candidate keys of R.

(e) Is your answer to (d) also in BCNF? Why or why not?