Consider the relation T1(A, B, C, D, E) with the dependencies {EB → C, D → E, EA → B} and T2(A, B, C, D) with the dependencies {C → A, A → B, A → D}. Which of the following is TRUE?

Explanation

T1: A and D never appear on a right side; (AD)⁺ = {A, D, E, B, C}, so AD is the only key and the prime attributes are A, D. D → E is a partial dependency (so T1 is not even in 2NF), and EB → C has a non-superkey LHS and a non-prime RHS, so T1 is not in 3NF. T2: the key is C; A → B and A → D are transitive dependencies, so T2 is not in 3NF either. Hence 'T1 is not in 3NF' is true.