Answer the following: --> If X and Y are subsets of attributes of relation R, th

Question

Answer the following:

--> If X and Y are subsets of attributes of relation R, then we say that set Y is functionally dependent

on set X if:

for each X value there is only one Y value

for each Y value there is only one X value

no two X values have the same Y value

when two rows have the same Y value they also have the same X value

--> Which of the following is not one of the major objectives of normalization?

removing redundancy

improving eciency

removing anomalies

increasing model exibility

--> A constraint between two or more attributes in which a nonkey attribute is determined by a portion

of the key is called a

partial functional dependency

partial attribute dependency

transitive dependency

partial transitive dependency

Explanation / Answer

DEFINATION : Functional dependency is a relationship that exists when one attribute uniquely determines another attribute. If R is a relation with attributes X and Y, a functional dependency between the attributes is represented as X->Y, which specifies Y is functionally dependent on X. The attributes of a table is said to be dependent on each other when an attribute of a table uniquely identifies another attribute of the same table.

1.improving model flexbiliy.we can safely assume that all other objectives are more important than this.

2.partial functional dependency.

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.