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Unit 4: Advanced Class Modelling – I

N-ary association: N-ary association is defined as an association among n classes. Notes
Qualifier: A qualifier is an attribute of an association class that reduces the multiplicity across an
association.

4.7 Review Questions

1. Explain the concept of class attributes and operations with example.
2. What is attribute multiplicity? Discuss with example.
3. Explain the concept of candidate keys for classes.
4. “It is important to record secondary information without obscuring the focus of an
application.” Comment.
5. What is an association end? Illustrate with example.
6. Describe the concept of role names and qualifier.

7. Discuss the concept of n-ary association with example.
8. What is aggregation? How is it different from association? Discuss.
9. What are different types of aggregation? Explain each with suitable examples.

10. What is recursive aggregation? Give suitable example of recursive aggregation.
Answers: Self Assessment

1. Instantiation 2. class operation
3. multiplicity 4. Attributes
5. enumeration 6. association end
7. rolename 8. Navigation

9. qualifier 10. Index
11. degree 12. N-ary
13. Aggregation 14. Fixed
15. recursive

4.8 Further Readings

Books Booch, Grady, (1994), Object-oriented Analysis & Design, Addison Wesley

Laganiere, Robert, (2004), Object-oriented Software Engineering, TMH
Rumbaugh, J., (2007), Object-oriented Modelling and Design with UML, Pearson
Education

Satzinger, (2007), Object-oriented Analysis & Design with the Unified Process, Thomson

Online links http://202.131.97.51/FACULTY/Maitri%20Patel/ooad/
solutions%20of%20excercise%20of%20ooad/oo4.pdf

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