Subject: Object Oriented Modeling and Design

Difficulty: Medium

Marks: 4 Marks

Multiplicity: -

Multiplicity specifies the number of instances of one class that mayrelate to a single instance of an associated class.

The UML specifies multiplicity with following notations:

• ”1” exactly one
• “1…*” One or more
• “3-5” three to five
• “0..1” zero to one
• “2,4,18” two, four or eighteen
• “*” denotes “many”.

Example:

Qualified association: Qualified association specifies relation between two object classes and a qualifier. The qualifier is a special attribute that reduces the effective multiplicity of an association. The qualifier distinguishes among the set of objects at the many end of an association. A qualifier is drawn as a small box on the end of the association line near the class it qualifies.

Notation:

Example: