Question 1

Within a specialization hierarchy, a supertype can exist only within the context of a subtype.

Accepted Answer

A) True 
 B)False

Question 2

In which two cases are composite primary keys particularly useful?

Accepted Answer

Composite primary keys are particularly ...

Question 3

Differentiate between specialization and generalization.

Accepted Answer

Specialization is the top-down process o...

Question 4

From a data modeling point of view, _____ data refer to data whose values change over time and for which one must keep a history of the data changes.

Accepted Answer

time-variant

Question 5

A _____ key is a real-world, generally accepted identifier used to uniquely identify real-world objects.

Accepted Answer

A)   primary
B)   natural
C)   foreign
D)   surrogateE) A) and D)
F) A) and C)

Question 6

To model time-variant data, one must create a new entity in an M:N relationship with the original entity.

Accepted Answer

A) True 
 B)False

Question 7

Composite keys are useful as identifiers of weak entities, where the weak entity has a strong _____ relationship with the parent entity.

Accepted Answer

The answer of Composite keys are useful as identifiers of...

Question 8

A partial completeness constraint is represented by _____.

Accepted Answer

A)   a dotted line
B)   two dashed lines
C)   a single horizontal line under a circle
D)   a double horizontal line over a circleE) A) and D)
F) A) and B)

Question 9

The property of _____ enables an entity subtype to inherit the attributes and relationships of the supertype.

Accepted Answer

A)   subtype discriminator
B)   inheritance
C)   specialization hierarchy
D)   entity supertypeE) B) and C)
F) None of the above

Question 10

A total completeness constraint is represented by a _____.

Accepted Answer

A)   smaller circle inside a bigger circle
B)   rhombus inside a circle
C)   double horizontal line under a circle
D)   single horizontal line above a circleE) B) and C)
F) A) and D)

Question 11

Which of the following is a specialization hierarchy disjoint constraint scenario in case of partial completeness?

Accepted Answer

A)   Subtype discriminator can be null.
B)   Subtype discriminator cannot be null.
C)   Each supertype occurrence is a member of only one subtype.
D)   Each supertype occurrence is a member of at least one subtype.E) A) and C)
F) B) and C)

Question 12

Overlapping subtypes are subtypes that contain a unique subset of the supertype entity set.

Accepted Answer

A) True 
 B)False  False

Question 13

While using a surrogate key, one must ensure that the candidate key of the entity in question performs properly through the use of the "_____" and "not null" constraints.

Accepted Answer

The answer of While using a surrogate key, one must...

Question 14

The "_____" characteristic of a primary key states that the primary key should not have embedded semantic meaning.

Accepted Answer

A)   unique values
B)   nonintelligent
C)   preferably single-attribute
D)   security-compliantE) B) and C)
F) All of the above B

Question 15

In the context of total completeness, in a(n)  _____, every supertype occurrence is a member of at least one subtype.

Accepted Answer

A)   unique constraint
B)   disjoint constraint
C)   overlapping constraint
D)   foreign key constraintE) B) and D)
F) B) and C)

Question 16

A(n)  _____ is the attribute in the supertype entity that determines to which entity subtype each supertype occurrence is related.

Accepted Answer

A)   subtype discriminator
B)   inheritance discriminator
C)   specialization hierarchy
D)   entity supertypeE) None of the above
F) A) and D)

Question 17

An entity supertype can have disjoint or overlapping entity subtypes.

Accepted Answer

A) True 
 B)False

Question 18

_____ keys work with primary keys to properly implement relationships in the relational model.

Accepted Answer

The answer of _____ keys work with primary keys to...

Question 19

The default comparison condition for the subtype discriminator attribute is the _____ comparison.

Accepted Answer

A)   nonequality
B)   less than
C)   greater than
D)   equalityE) A) and D)
F) All of the above

Question 20

Composite primary keys are particularly useful as identifiers of composite entities, where each primary key combination is allowed _____ in the M:N relationship.

Accepted Answer

The answer of Composite primary keys are particularly useful as...

Exam 5: Advanced Data Modeling

Within a specialization hierarchy, a supertype can exist only within the context of a subtype.

Correct AnswerverifiedShow Answer

In which two cases are composite primary keys particularly useful?

Correct AnswerverifiedComposite primary keys are particularly ...View AnswerShow Answer

Differentiate between specialization and generalization.

Correct AnswerverifiedSpecialization is the top-down process o...View AnswerShow Answer

From a data modeling point of view, _____ data refer to data whose values change over time and for which one must keep a history of the data changes.

Correct Answerverifiedtime-variant

A _____ key is a real-world, generally accepted identifier used to uniquely identify real-world objects.

Correct AnswerverifiedShow Answer

To model time-variant data, one must create a new entity in an M:N relationship with the original entity.

Correct AnswerverifiedShow Answer

Composite keys are useful as identifiers of weak entities, where the weak entity has a strong _____ relationship with the parent entity.

Correct AnswerverifiedShow Answer

A partial completeness constraint is represented by _____.

Correct AnswerverifiedShow Answer

The property of _____ enables an entity subtype to inherit the attributes and relationships of the supertype.

Correct AnswerverifiedShow Answer

A total completeness constraint is represented by a _____.

Correct AnswerverifiedShow Answer

Which of the following is a specialization hierarchy disjoint constraint scenario in case of partial completeness?

Correct AnswerverifiedShow Answer

Overlapping subtypes are subtypes that contain a unique subset of the supertype entity set.

Correct AnswerverifiedFalse

While using a surrogate key, one must ensure that the candidate key of the entity in question performs properly through the use of the "_____" and "not null" constraints.

Correct AnswerverifiedShow Answer

The "_____" characteristic of a primary key states that the primary key should not have embedded semantic meaning.

Correct AnswerverifiedB

In the context of total completeness, in a(n) _____, every supertype occurrence is a member of at least one subtype.

Correct AnswerverifiedShow Answer

A(n) _____ is the attribute in the supertype entity that determines to which entity subtype each supertype occurrence is related.

Correct AnswerverifiedShow Answer

An entity supertype can have disjoint or overlapping entity subtypes.

Correct AnswerverifiedShow Answer

_____ keys work with primary keys to properly implement relationships in the relational model.

Correct AnswerverifiedShow Answer

The default comparison condition for the subtype discriminator attribute is the _____ comparison.

Correct AnswerverifiedShow Answer

Composite primary keys are particularly useful as identifiers of composite entities, where each primary key combination is allowed _____ in the M:N relationship.

Correct AnswerverifiedShow Answer

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Composite primary keys are particularly ...
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Specialization is the top-down process o...
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time-variant

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False

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B

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