Question

Relationship "has" 2 rules:

Disjoint:
Specifies that the subclasses of the specialization must be disjoint; an entity can be a member of at most one of the subclasses of the specialization. Expressed as d in EER diagram.
Overlapping:
If not disjoint, the specialization is overlapping which means that the same entity may be a member of more than one subclass of the specialization. Expressed as o in EER diagram.
Options:
A. Exclusive, Inclusive
B. Separated, United
C. Singular, Collective
D. Distinct, Shared

Answer 1

In database design, relationships in ER diagrams are classified as Disjoint, meaning exclusive, or Overlapping, meaning inclusive. A Disjoint relationship prohibits an entity from being in more than one subclass, whereas Overlapping allows it.

Step-by-step explanation:

In the context of an Entity-Relationship (ER) diagram within the realm of database design, a relationship has two rules concerning how entities relate to their subclasses in a specialization: Disjoint and Overlapping.

A Disjoint subtype relationship, indicated with a 'd' in Enhanced Entity-Relationship (EER) diagrams, means that an entity can only belong to one subclass; that is, subclasses are exclusive. For instance, in a database handling animal species, a specific animal can either be classified as a mammal or a reptile but not both, illustrating a disjoint relationship between these two subclasses of the animal kingdom.

An Overlapping subtype relationship allows entities to belong to multiple subclasses simultaneously and is indicated with an 'o' in EER diagrams. This is akin to an individual being a member of different organizations at the same time, reflecting that the classifications are inclusive of one another.

Therefore, the correct answer that corresponds to the rules of Disjoint (Exclusive) and Overlapping (Inclusive) is:

A. Exclusive, Inclusive