Exam 3: The Enhanced E-R Model

Which of the following is true of packaged data models?

A ________ addresses whether an instance of a supertype may simultaneously be a member of two or more subtypes.

Packaged data models use an entity type to store union data.

The following figure is an example of the overlap rule.

Because a purchased data model is extensive, you begin by identifying the parts of the data model that apply to your data modeling situation.

The following diagram shows:

Which of the following statements is true about the figure shown below?

The ________ rule specifies that an entity can be a member of only one subtype at a time.

An attribute of the supertype that determines the target subtype(s) is called the:

A subtype can become a supertype if the subtype has other subtypes beneath it.

The total specialization rule states that an entity instance of a supertype is allowed not to belong to any subtype.

Compare and contrast generalization and specialization.

A member of a subtype does NOT necessarily have to be a member of the supertype.

Packaged data models can be developed using proven components.

Discuss how attributes are assigned in a supertype/subtype hierarchy.

Discuss the reasoning behind using supertype/subtype relationships.

The subtype discriminator is a composite attribute when there is a(n):

Packaged data models are meant to be customized.

The following figure shows an example of:

Discuss when one would use total specialization and when one would use partial specialization.