Question

Assume that attributes with the same name in different relations represent the same domain and that the primary key attributes in each relation are underlined. Answer the following questions given the relational schema below:

R(A,D)
S(A,B,C,D)
T(C,D,A,H)

1. List all potential foreign keys in the three relations. (1 mark)
2. List all superkeys of S. (1 mark)
3. List all candidate keys of T. (1 mark)
4. What is the degree and cardinality of S? (1 mark)
5. If the cardinality of T is N, what is the cardinality of π_C,H(T)? (1 mark)

Answer 1