Database.... Mark each question True or False and explain why you made your choi

Question

Database.... Mark each question True or False and explain why you made your choice.

. A deletion anomaly occurs when deleting one entity results is deleting facts about another entity.

· A relation is in first normal form if all of its non-key attributes are dependent on part of the key.

· A relation can be in third normal form without being in second normal form.

· A relation is in Boyce-Codd normal form if every determinant is a candidate key.

· If attribute A determines B, but B does not determine A, the relationship among their data values is one-to-one.

· In a 1: N relationship, we can navigate from either relation to the other.

· A form is a screen display used only to present data to the user.

Explanation / Answer

(i) false, because deletion anomaly occurs by the deletion of facts about an entity automatically deletes the fact of another entity. (ii) flase, because first normal form can not be decided by partial dependency, i.e. non key attribute depending on part of candidate key. A relation is in first normal form if each attribute of a relation holds atomic value, i.e. a attribute can not hold multiple values. (iii) false, by the definition of third normal form a relation must be in second normal form, and every non-key attribute is non-transitively dependent on the primary key (iv) true, By definition of Boyce-Codd Normal Form(BCNF), a relation is in BCNF, if and only if every determinant is a candidate key.

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