Which constraint prevents duplicate values in a database column?
Options
A.
DEFAULT Constraint
B.
UNIQUE Constraint
C.
CHECK Constraint
D.
More than one of the above
E.
None of the above
Correct Answer (Detailed Explanation is Below)
B.
UNIQUE Constraint
Detailed Explanation
Explanation: The UNIQUE constraint ensures that duplicate values are not allowed in a column or combination of columns. NULL handling may vary by DBMS.