5. Consider the following relation schema S(A, B, C, D, E) and a set of functional dependencies:

AB-C

CD-E

1 Keep in mind, these may not be "true" FDs though, because we will determine them exclusively based on the current

data (i.e., a particular instance of relation) and changing that data can change FDs as well.

DE-B

a) Show that ADE is a candidate key (proof with step-by-step justification).

b) Other candidate keys for this set of FDs are ABD and ACD. Given that, show why this relation is

not in BCNF. Explain.

c) Give a lossless decomposition into BCNF. Do it step by step, illustrating each split, similar to how

we do it in our presentation. List candidate keys for all resulting tables. List all remaining FDs.