Question 1

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

Accepted Answer

A) True 
 B)False

Question 2

The following figure shows a:

Accepted Answer

A)   disjoint constraint.
B)   completeness constraint.
C)   supertype/subtype hierarchy.
D)   spindle constraint.E) C) and D)
F) A) and B)

Question 3

In a supertype/subtype hierarchy, subtypes that are lower in the hierarchy inherit attributes from not only their immediate supertype but from all ________ in the hierarchy.

Accepted Answer

A)   subtypes
B)   supertypes
C)   constraints
D)   dimensionsE) B) and C)
F) B) and D)

Question 4

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

Accepted Answer

When we have overlapping subty...

Question 5

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

Accepted Answer

A)   disjoint
B)   overlap
C)   partial specialization
D)   total specializationE) All of the above
F) A) and B)

Question 6

An entity cluster is:

Accepted Answer

A)   a formal method for specifying attributes of related entities.
B)   a set of one or more entity types and associated relationships grouped into a single abstract entity type.
C)   a useful way to present data for a small and fairly simple organization.
D)   a way of developing more granular views of the data model.E) All of the above
F) A) and D)

Question 7

Packaged data models cause projects to take more time to build.

Accepted Answer

A) True 
 B)False  False

Question 8

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

Accepted Answer

A) True 
 B)False

Question 9

Which of the following is a completeness constraint?

Accepted Answer

A)   Total specialization
B)   Partial generalization
C)   Total recall
D)   Partial hybridizationE) C) and D)
F) A) and D)

Question 10

Explain the terms subtype and supertype. Discuss the differences between them.

Accepted Answer

A subtype is an entity which represents ...

Question 11

The following figure is an example of total specialization.

Accepted Answer

A) True 
 B)False  False

Question 12

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

Accepted Answer

A) True 
 B)False  True

Question 13

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

Accepted Answer

A) True 
 B)False

Question 14

Discuss the reasoning behind using supertype/subtype relationships.

Accepted Answer

It is best to use a supertype/subtype hi...

Question 15

The following figure shows an example of:

Accepted Answer

A)   the disjoint rule.
B)   the completeness rule.
C)   the underdog rule.
D)   the overlap rule.E) B) and C)
F) A) and C)

Question 16

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

Accepted Answer

A) True 
 B)False

Question 17

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

Accepted Answer

A)   overlap rule.
B)   disjoint rule.
C)   partial specialization.
D)   full specialization.E) C) and D)
F) B) and D)

Question 18

The process of defining a more general entity type from a set of more specialized entity types is called:

Accepted Answer

A)   generalization.
B)   specialization.
C)   normalization.
D)   extrapolation.E) A) and B)
F) A) and C)

Question 19

A subtype is a generic entity that has a relationship with one or more entities at a lower level.

Accepted Answer

A) True 
 B)False

Question 20

In packaged data models, strong entities always have ________ between them.

Accepted Answer

A)   weak entities
B)   1:1 relationships
C)   1:M relationships
D)   M:N relationshipsE) A) and D)
F) A) and C)

Exam 3: The Enhanced E-R Model

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

Correct AnswerverifiedShow Answer

The following figure shows a:

Correct AnswerverifiedShow Answer

In a supertype/subtype hierarchy, subtypes that are lower in the hierarchy inherit attributes from not only their immediate supertype but from all ________ in the hierarchy.

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedWhen we have overlapping subty...View AnswerShow Answer

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

Correct AnswerverifiedShow Answer

An entity cluster is:

Correct AnswerverifiedShow Answer

Packaged data models cause projects to take more time to build.

Correct AnswerverifiedFalse

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

Correct AnswerverifiedShow Answer

Which of the following is a completeness constraint?

Correct AnswerverifiedShow Answer

Explain the terms subtype and supertype. Discuss the differences between them.

Correct AnswerverifiedA subtype is an entity which represents ...View AnswerShow Answer

The following figure is an example of total specialization.

Correct AnswerverifiedFalse

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

Correct AnswerverifiedTrue

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

Correct AnswerverifiedShow Answer

Discuss the reasoning behind using supertype/subtype relationships.

Correct AnswerverifiedIt is best to use a supertype/subtype hi...View AnswerShow Answer

The following figure shows an example of:

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

The process of defining a more general entity type from a set of more specialized entity types is called:

Correct AnswerverifiedShow Answer

A subtype is a generic entity that has a relationship with one or more entities at a lower level.

Correct AnswerverifiedShow Answer

In packaged data models, strong entities always have ________ between them.

Correct AnswerverifiedShow Answer

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When we have overlapping subty...
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False

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A subtype is an entity which represents ...
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False

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True

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It is best to use a supertype/subtype hi...
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