The UNIQUE Constraint Differs from the PRIMARY KEY Constraint in What

question 47

Multiple Choice

The UNIQUE constraint differs from the PRIMARY KEY constraint in what way?

• A) The UNIQUE constraint does not allow NULL values.
• B) The UNIQUE constraint can be created at either the column level or the table level.
• C) The UNIQUE constraint allows NULL values.
• D) The UNIQUE constraint ensures that a specific condition is True before a data value is added to a table.

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Definitions:

Confirmation Bias

A bias towards identifying, comprehending, selecting, and reminiscing information that supports and validates one's existing beliefs or assumptions.

Self-Fulfilling Prophecy

A prediction that directly or indirectly causes itself to become true.

Cognitive Functionality

The intellectual processes by which an individual understands, reasons, thinks, and remembers information.

Self-Fulfilling Prophecy

A belief or expectation that directly or indirectly causes itself to become true, due to positive feedback between belief and behavior.