Which statements are true regarding constraints? Select one or more: Af i k t t i NULL l A foreign key cannot contain NULL values. A constraint is enforced only for the INSERT operation on a table. A columns with the UNIQUE constraint can contain NULL values. A constraint can be disabled even if the constraint column contains data.
Answer options
A
A columns with the UNIQUE constraint can contain NULL values. A constraint can be disabled even if the constraint column contains dat
B
, A columns with the UNIQUE constraint can contain NULL values.
Correct answer: A columns with the UNIQUE constraint can contain NULL values. A constraint can be disabled even if the constraint column contains dat
Explanation
Quick AnswerThe correct answer is A columns with the UNIQUE constraint can contain NULL values. A constraint can be disabled even if the constraint column contains dat because it directly addresses the core logic of Database Management.
UNIQUE columns can contain NULL; constraints can be disabled while data exists.