A relation is in third normal form (3NF)if and only if it is in 2NF and ________.
A)all non-key attributes are determined by the entire primary key
B)there are no non-key attributes determined by another non-key attribute
C)every attribute is a candidate key
D)every candidate key is a determinant

Question

Quizplus · Accepted Answer

To be in 3NF, a relation must first be in 2NF, which means that all non-key attributes must depend on the entire primary key, and partial dependencies must be eliminated. In addition, in 3NF, there should be no transitive dependencies, which means that no non-key attribute should be determined by another non-key attribute. Option A is incorrect because not all non-key attributes need to be determined by the entire primary key. Option C is incorrect because if every attribute is a candidate key, then the relation is likely to be in BCNF rather than 3NF. Option D is incorrect because not every candidate key needs to be a determinant in 3NF.

A Relation Is in Third Normal Form (3NF)if and Only