Repeat Exercise 3.2.1 for the following schemas and sets of FD’s:

Exercise 3.2.1

Consider a relation with schema R(A,B,C ,D ) and FD’s A B → C , C → D , and D → A.

a) What are all the nontrivial FD’s that follow from the given FD’s? You should restrict yourself to FD’s with single attributes on the right side.

b) What are all the keys of R?

c) What are all the super keys for R that are not keys?