Which two statements are true regarding constraints? (Choose two.)
A.
A foreign key cannot contain NULL values.
B.
A column with the UNIQUE constraint can contain NULL.
C.
A constraint is enforced only for the INSERT operation on a table.
D.
A constraint can be disabled even if the constraint column contains data.
E.
All the constraints can be defined at the column level as well as the table level.
E is also correct as per..
Constraints are the rules enforced on data columns on table. These are used to limit the type of data that can go into a table. This ensures the accuracy and reliability of the data in the database.
Constraints could be column level or table level. Column level constraints are applied only to one column, whereas table level constraints are applied to the whole table.
Not E.
NOT NULL constraint can be defined ONLY at the column level.
I choose BD