A Candidate Key of a Relation That Is Not Chosen

question 35

Multiple Choice

A candidate key of a relation that is not chosen to be the primary key ____.

• A) is called a foreign key
• B) is called an alternate key
• C) is called a relationship key
• D) does not have to have unique values
• E) does not have to be wholly contained within the relation

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Definitions:

Canalization

The tendency for a trait that is biologically programmed to be restricted to only a few outcomes.

Range of Reaction

A theory suggesting that genetic potential sets certain limits on the expression of traits, but the environment determines where within those limits an individual will fall.

Epigenesis

The process through which the genotype interacts with the environment to guide development, affecting gene expression without altering the DNA sequence.

Passive Correlation

A statistical relationship between two variables where changes in one variable occur alongside but are not directly caused by changes in the other.