Explanation: A Table is in 4NF if and only if, for every one of its non-trivial multivalued dependencies X \twoheadrightarrow Y, X is a superkey—that is, X is either a candidate key or a superset thereof. 6. If a multivalued dependency holds and is not implied by the corresponding functional dependency, it usually arises from one of the following sources.
A. A many-to-many relationship set
B. A multivalued attribute of an entity set
C. A one-to-many relationship set
D. Both a and b
Answer:A
Explanation: A Table is in 4NF if and only if, for every one of its non-trivial multivalued dependencies X \twoheadrightarrow Y, X is a superkey—that is, X is either a candidate key or a superset thereof. 6. If a multivalued dependency holds and is not implied by the corresponding functional dependency, it usually arises from one of the following sources.
A. A many-to-many relationship set B. A multivalued attribute of an entity set C. A one-to-many relationship set D. Both a and b
Explanation: For a many-to-many relationship set each related entity set has its own schema and there is an additional schema for the relationship set. For a multivalued attribute, a separate schema is created consisting of that attribute and the primary key of the entity set. 7. Which of the following has each related entity set has its own schema and there is an additional schema for the relationship set?