Which statement regarding NOT ENFORCED unique constraints is true?
A.
NOT ENFORCED unique constraints enforce uniqueness only for primary key columns.
B.
The query optimizer will consider a NOT ENFORCED unique constraint when selecting the
optimal data access plan.
C.
Storage requirements for NOT ENFORCED unique constraints are identical to storage
requirements for a unique index.
D.
When attempting to insert data that does not conform to the NOT ENFORCED unique
constraint, an error will be returned and the record will not be inserted.