Exam 3: The Enhanced E-R Model

Explain why the E-R model needed to be expanded into the enhanced E-R model.

Generalization is a top-down process.

The third step in the data modeling process with a packaged data model is:

Contrast the overlap rule to the disjoint rule.

Entity clustering is a methodology for grouping one or more entity types and associated relationships into a single abstract entity type.

When subtypes are overlapping, an additional field must be added to the supertype to act as a discriminator.

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

The ________ rule states that an entity instance can simultaneously be a member of two (or more) subtypes.

In packaged data models, all subtype/supertype relationships follow the ________ and ________ rules.

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

In the figure below, a student:

Adapting a packaged data model from your DBMS vendor makes it difficult for the application to work with other applications from the same vendor.

In the figure shown below, there could be an instance of a rental unit that is neither an apartment nor a house.

In the figure below, which of the following is a subtype of patient?

The ________ rule specifies that an entity instance of a supertype is allowed not to belong to any subtype.

How is the data modeling process different when starting with a purchased solution?

All of the following are steps to using a packaged data model EXCEPT:

You will never need to map data in current databases to data in a packaged data model.

The following figure is an example of total specialization.

In the figure shown below, a rental unit has to be either a house or an apartment.