What is the importance of association multiplicity in class diagrams?
associations, class-diagram, multiplicity
Solution
They allow the designer a quick visual way of communication that would be difficult without multiplicities. You would have to use notes or other space-eating annotations in the diagram.
In a UML diagram I want to have multiplicities for all other associations other than one-on-one.
Why?
- One-on-one is the visual cue you get from a simple association. It's sort of the default.
- Multiplicities contain domain knowledge (car->wheel is usually a 1 -> 4 association. The association without the multiplicity looks like a car has one wheel.
- A designer can "deserialize" the things he thinks are granted because everybody in the domain probably knows them, but the developer probably does not know!
Problem
What is the importance of association multiplicity in class diagrams? Why and when should we indicate them? Thanks.