UML Weekend Crash Course™ - To Parent Directory

SESSION
10
The Class Diagram: Associations
Session Checklist
✔ Explaining and illustrating the basic notation for all associations
✔ Explaining and illustrating the notations for association classes,
reflexive associations, and qualified associations
Associations between objects are similar to associations between people. In order for
me to work with you, I need to communicate with you. This requires that I have
some way to contact you, such as a phone number or an e-mail address. Further, it is
often necessary to identify why we are associated in order to clarify why we do and do not
participate in certain kinds of communication. For example, if we are associated because
you are a programmer and I am a database administrator, we probably will not discuss
employee benefits as part of our duties.
There would also probably be some limitations placed on our interactions:
We would want to limit the number of participants in the relationship to ensure
efficiency.
We would want to check the qualifications of the participants to ensure we have the
right participants.
We would want to define the roles of the participants so that everyone knows how
to behave.
All these requirements apply equally to objects. The UML provides notations to address
them all. I’ll start with the basics and then add a few twists.