the association between two instances like Branch and Customer.
Example cardinality associations:
Each branch can have 0 to multiple customers (*).
Each Bank can have multiple Branches
Each Account can be associated with multiple customers
rolenames
labels for the cardinality constraints or as attributes of the
type furthest away from where they are written. For example, holder
can be thought of as an attribute of Account, constrained to hold
between 1 and 2 values of type Customer.
Associations Inherieted -single and multiple inheritance