The ____ constraint is similar to the PRIMARY KEY constraint because both enforce unique values;the difference is that it allows null values in the column or columns that are named in the constraint.
A) CHECK
B) FOREIGN KEY
C) UNIQUE
D) NOT NULL

Question

Quizplus · Accepted Answer

The UNIQUE constraint enforces unique values in a column or group of columns, similar to the PRIMARY KEY constraint. The difference is that it allows NULL values in the column(s) that are named in the constraint. The CHECK constraint is used to ensure that values in a column meet a certain condition, the FOREIGN KEY constraint is used to ensure referential integrity between tables, and the NOT NULL constraint is used to ensure that a column cannot have NULL values.

The ____ Constraint Is Similar to the PRIMARY KEY Constraint