ER MODEL AND BUSINESS RULES QUIZ

Use of a supertype/subtype relationship is necessary when which of the following exists?

An instance of a subtype participates in a relationship that is unique to that subtype.

An instance of a subtype participates in a relationship that is the same as the other subtypes.

Attributes apply to all of the instances of an entity type.

No attributes apply to any of the instances of an entity type.

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A subtype discriminator of the supertype is an attribute whose values determine the target subtype(s).

True

False

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An action assertion must include which of the following?

Corresponding object

Action

All of these

Anchor object

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Which one of the following symbols is not used in an ERD?

Diamond

Rectangle

Circle

Oval

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A supertype/subtype hierarchy has which of the following features?

Subtypes at the higher lever in the hierarchy inherit attributes only from their immediate subtype.

Attributes are assigned at the lowest logical level.

Attributes are assigned at the highest logical level.

Subtypes at the lower lever in the hierarchy inherit attributes only from their immediate supertype.

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It is appropriate to use a supertype/subtype relationship when there are attributes that apply to some of the instances of an entity type.

True

False

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An ERD that has had the entities clustered will display more entities.

True

False

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A supertype is an entity type that shares common attributes or relationships distinct from other subgroupings.

False

True

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When an entity instance may be a member of multiple subtypes or it does not have to be a member of a subtype, it is which of the following?

Disjoint with total specialization

Disjoint with partial specialization

Overlap with total specialization

Overlap with partial specialization

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There is cardinality on an EER between the supertype and subtype.

True

False

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