Which two statements are true regarding constraints? (Choose two.)
A.
A foreign key cannot contain NULL values.
B.
The column with a UNIQUE constraint can store NULLS .
C.
A constraint is enforced only for an INSERT operation on a table.
D.
You can have more than one column in a table as part of a primary key.
A column can be Unique and Null
B&D
D.
A constraint can be disabled even if the constraint column contains data. -Correct
E.
All the constraints can be defined at the column level as well as the table level. – False, Not Null can’t is only a column level constraint