Suppose we have three relations r(A, B), s(B, C), and t(B, D), with all attributesdeclared as not null. Are there instances of r, s, and t such that the result ofr natural left outer join (s natural left outer join t) has a null value for C but a non-null value for D? Explain why or why not.

Let's suppose, a relation R=(A, B, C, D, E. H) with a set of functional dependencies F: (AE->BC, B ->AD, CD->E, E→CD, A->E) is given. Relation R (A, B, C, D, E, H) is decomposed into R1 (A, B, C, D) and R2 (A, B, E, H). Find out whether the decomposition is lossless or not, and whether it is dependency preserving or not.

For a given relationship set, R = {A, B, C, D, E, F} and FD : A->B, C->D, E->F . Calculate F+ of A, B, C, D, E, F and find the candidate key from this relationship. Do you think this relation is in 2NF form? why or why not?

Answer correctly