4. Identify relationship types between object types
Object types are connected to each other through a number of relationship types
- Relationship (instances) can not exist independently!
Relationships can be distinguished by their:
- Semantics
- sometimes difficult, e.g. association vs. aggregation in UML
- Properties
- defined similarly than with object types
- Notational differences
Relationship types are defined as components:
- Their connection to object types (and role types) are specified later