4.2) (5 points) Assume we have two relations R(a,b) and S(b,c). All three attributes (a, b,...

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4.2) (5 points) Assume we have two relations R(a,b) and S(b,c). All three attributes (a, b, and c) are integer attributes. Assume that Relation R contains the following tuples: (1,2), (2,3), (4,7) and (3,4). Assume that Relation S contains the following tuples (2,2), (2,3), (4,6) and (7,5). a) (1 Points) Give an example of an attribute (or a combination of attributes) that cannot be a primary key for relation S, why? b) (1 Points) How many tuples are in the result of the Cartesian Product between R and S? c) (1 Points) How many tuples are in the result of Natural Join between R and S? d) (2 Points) Show the output of the following query SELECT a FROM R,S = WHERE Rb Sb and S.c>2 4.2) (5 points) Assume we have two relations R(a,b) and S(b,c). All three attributes (a, b, and c) are integer attributes. Assume that Relation R contains the following tuples: (1,2), (2,3), (4,7) and (3,4). Assume that Relation S contains the following tuples (2,2), (2,3), (4,6) and (7,5). a) (1 Points) Give an example of an attribute (or a combination of attributes) that cannot be a primary key for relation S, why? b) (1 Points) How many tuples are in the result of the Cartesian Product between R and S? c) (1 Points) How many tuples are in the result of Natural Join between R and S? d) (2 Points) Show the output of the following query SELECT a FROM R,S = WHERE Rb Sb and S.c>2