What would have to appear in the data model in order for every entity instance i

Question

What would have to appear in the data model in order for every entity instance in a supertype PRODUCT entity to be associated with an entity instance in the subtype CD entity?

a. A single subtype discriminator would need to be present in the supertype PRODUCT that is set to “CD”

b. A discriminator attribute for the CD entity would need to be present in the supertype PRODUCT entity that is set to “I” or “ TRUE”

c. The total completeness constraint would need to be set on the subtype CD entity only.

d. None of these

Explanation / Answer

Q1) What would have to appear in the data model in order for every entity instance in a supertype PRODUCT entity to be associated with an entity instance in the subtype CD entity

d. None of these [Reason - In Data Model for Order we need to have discriminator for ProductID, since every instance of CD Entity is also of type Product only, its a subtype of PRODUCT, which is a super type.]

Please let me know in case of any clarifications required. Thanks!

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