The UNIQUE Constraint Differs from the PRIMARY KEY Constraint in What

question 4

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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