Exam 3: The Enhanced E-R Model

One of the major challenges in data modeling is to recognize and clearly represent entities that are almost the same.

The following figure is an example of:

Subtypes should be used when:

The property by which subtype entities possess the values of all attributes of a supertype is called:

Data models of an existing database are harder for data modelers to read.

In the figure below, which of the following apply to both OUTPATIENTs and RESIDENT_PATIENTs?

Why are packaged data models gaining popularity?

Using a packaged data model, projects take less time and cost because:

The subtype discriminator in the figure below is:

An entity cluster is:

The most important challenge of customizing a purchased data model is:

Describe how subtype discriminators are used when we have overlapping subtypes.

In the figure below, to which of the following entities are the entities "CAR" and "TRUCK" generalized?

An entity cluster should focus on some area of interest to some community of users, developers or managers.

A(n) ________ constraint is a type of constraint that addresses whether an instance of a supertype must also be an instance of at least one subtype.

Mapping existing data to new data in a packaged data model is useful for developing migration plans.

A generic or template data model that can be reused as a starting point for a data modeling project is called a(n):

Supertype/subtype relationships should be used when the instances of a subtype participate in no relationships which are unique to that subtype.

In the figure shown below, a rental unit can be both an apartment and a house but must be at least one.

The ________ rule specifies that each entity instance of the supertype must be a member of some subtype in the relationship.