Consider the relation R(A, B, C, D, E) with FDs C rightarrow AD, DE rightarrow B
ID: 3777922 • Letter: C
Question
Consider the relation R(A, B, C, D, E) with FDs C rightarrow AD, DE rightarrow B, A rightarrow E, and B rightarrow C. List all the keys of R. Indicate which FDs are BCNF violations. Decompose R, if necessary, into relations that are in BCNF. You can choose any BCNF violations you want to do the decomposition. Show your work. Is the result of your decomposition dependency-preserving? In other words, is the set of FDs that hold in the individual relations in your decomposition equivalent to the original set of FDs in R? Explain your answer. If your decomposition is not dependency-preserving, re-decompose R into 3NF. Show your work.Explanation / Answer
Multipple questions : Answering 1st.
Solution :
(C)+: CADEB (SuperKey)
(B)+: BCADE (SuperKey)
(DE)+: DEBCA (SuperKey)
(DA)+: DAEBC (SuperKey)
Any combination of attributes that includes those is a superkey.
From above , the minimal super keys are C, D, DE and AD.
Hence, the keys are C, D, DE and AD.