If a 1:M relationship is optional on the 1 side and mandatory on the M side, which of the following is true?
A) The resulting foreign key can have null (empty) values
B) The resulting foreign key cannot have null (empty) values
C) The resulting foreign key must have null (empty) values
D) No foreign key is created as a result of mapping such a relationship
A
You might also like to view...
A real estate broker, acting as agent for a landlord, has the following instructions: Instruction I. Collect a larger deposit from single men than from single women or couples; Instruction II. Advertise only by encouraging existing tenants who are predominantly white to solicit prospective tenants from among their friends. Which of these instructions would be prohibited by the Federal Fair Housing Act:
A: I only; B: II only; C: Both; D: Neither.
_________ involves counting the number of occurrences of a specific event type over an interval of time.
A) ?Rule-based detection ? ? B) ?Resource usage C) ?Threshold detection ? ? D) ?Profile-based system