Question

Which of the following can be addressed by enforcing a referential integrity constraint?

(a) All phone numbers must include the area code

(b) Certain fields are required (such as the email address, or phone number) before the record is accepted

(c) Information on the customer must be known before anything can be sold to that customer

(d) Then entering an order quantity, the user must input a number and not some text (i.e., 12 rather than ‘a dozen’)

I have been asked this question by my school principal while I was bunking the class.

Origin of the question is Constraints topic in chapter Database Systems Design and Implementation of Database Management

Answer 1

Correct option is (c) Information on the customer must be known before anything can be sold to that customer

To explain: None.