Classes' diagrams

Associations are relations and also particular classes having source & target elements.

Associations

Associations have:

• A name (optional)
• Roles for each extremity (optional)
• Multiplicity/cardinality that restrict the number min..max of links (default is 1..1)

Associations can also:

• Have navigability to restrict the messages' flow (eg. only from Group to Element in the figure)
• Be composition or aggregation to stipulate, for instance, that the elements of a group must be destructed when this one is deleted.