Modeling UML Associations - Quiz Explanation
The answers you selected are indicated below, along with text that explains the correct answers.
1.
The multiplicity designation
*
means
Please select the best answer.
A.
Unspecified
B.
Zero or more
C.
Many
D.
Enumerated list
The correct answer is B.
The multiplicity designation
*
means zero or more. A is incorrect because "unspecified" means that no decision has been made. "Many" is sometimes used but is not completely accurate, so C is incorrect. D is incorrect because an enumerated list identifies a set of multiplicity values separated by commas such as 4,7,9.
2.
The multiplicity designation
1..*
means
Please select the best answer.
A.
One or more
B.
Minimum of one, but upper limit is unspecified
C.
Enumerated list starting at one
D.
One or zero
The correct answer is A.
The multiplicity designation
1..*
means one or more. B is incorrect because the asterisk has a specific meaning; that is "unspecified" means that a decision has not been made where
*
means no upper limit. Zero or one would be specified using
0..1
notation, so D is also incorrect.
3.
The minimum requirement for defining an association is
Please select the best answer.
A.
An association name
B.
An association name or roles and multiplicity on at least one end of the association
C.
Multiplicity on each end of the association
D.
An association name or roles and multiplicity on each end of the association
The correct answer is D.
The minimum requirement for defining an association is an association name or roles and multiplicity on each end of the association. You could argue that multiplicity is not required for implementation if you do not plan to navigate in a given direction. However, domain rules typically dictate the multiplicity whether the application uses that navigation path or not. None of the other answers includes all the required elements, so A, B, and C are incorrect.
4.
Constraints
Please select the best answer.
A.
Are used only on use case associations and classes
B.
Are written on the association line
C.
Are enclosed in brackets at the end of the association
D.
Define the role that an object assumes in an association
The correct answer is C.
Constraints are enclosed in brackets at the end of the association. A is incorrect because constraints may be used on many different model elements. B is incorrect because constraints must be enclosed in the constraint brackets. Roles are a different model element than constraints, so D is incorrect.
5.
Roles
Please select the best answer.
A.
Describe a constraint on an object
B.
Describe the function of an object when it participates in the association
C.
Are a replacement for an association name when an appropriate verb expression is difficult to find
D.
Appear in the middle of the association line
The correct answer is B.
Roles describe the function of an object when it participates in the association. Roles are different from constraints so A is incorrect. Roles are an alternative to an association name but they may also be used together with an association name, so C is incorrect. D is incorrect because roles are positioned at the ends of the association next to the class that they describe.
6.
A range of values for multiplicity is defined by
Please select the best answer.
A.
An asterisk
B.
Comma-separated values for minimum and maximum
C.
An asterisk followed by minimum and maximum values
D.
Two values separated by two periods
The correct answer is D.
A range of values for multiplicity is defined by two values separated by two periods
n..
. A is incorrect because the asterisk denotes zero or more. B is incorrect because comma-separated values denote an enumerated list of options. C is incorrect because this combination of values is never used.
UML Distilled
