If OrderNumber serves as the primary key in the ORDER relation and also appears as a nonkey attribute in the INVOICE relation, then OrderNumber is said to be a:
A) foreign key.
B) candidate key.
C) pointer.
D) relationship key.
E) marker.

Question

Quizplus · Accepted Answer

In this scenario, OrderNumber is acting as a link between the ORDER and INVOICE relations. As it is a primary key in the ORDER relation and a nonkey attribute in the INVOICE relation, it is called a foreign key. A foreign key is a field in one relation that uniquely identifies a row of another relation. It creates a relationship between the two relations and ensures data consistency between them. Hence, option A is the correct choice.

If OrderNumber Serves as the Primary Key in the ORDER