If order number serves as the primary key in the ORDER relation and also appears as a nonprimary key attribute in the INVOICE relation,then order number is said to be a:
A)foreign key
B)candidate key
C)pointer
D)relationship key

Question

Quizplus · Accepted Answer

If an attribute in one relation serves as the primary key and appears as a non-primary key attribute in another relation, then it is known as a foreign key. In this case, order number acts as the primary key in the ORDER relation and appears as a non-primary key attribute in the INVOICE relation, which means that it uniquely identifies an order in the ORDER relation and helps establish a relationship between the two relations. Thus, the correct answer is A) foreign key.

If Order Number Serves as the Primary Key in the ORDER