Class diagram
Basic class diagram
Four classes showing inheritance, composition and aggregation.
- Category
- Technical
- Diagram type
- Class diagram
- Elements
- 4
- Connectors
- 3
What it is for
Three of the core relationships side by side, so you can see the notation rather than looking it up. Aggregation and composition differ only by diamond fill, and mean different things about lifetime: a Session cannot outlive its User, but a Role exists whether or not any Admin holds it.
More about the class diagram makerWhen it helps
- Learning UML notation
- A design discussion starting point
- Teaching object modelling
