Let $R(A,B,C,D)$ be a relation whose schema satisfies the set of functional dependencies

$ACD$

$CD$

$DB$

$(12$ points$)$ Find all subsets of the schema of $R$ and compute closures for all non$-$empty

subsets of R$.$

$(12$ points$)$ Identify all non$-$trivial functional dependencies and list all keys.

$(7$ points$)$ List all BCNF violations.

$(25$ points$)$ Decompose R$,$ as necessary into collections of relations that are in BCNF$.$