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Also, don't list as an attribute what you also draw as an aggregation. If you denote
by aggregation the fact that a
Car
has
Tire
objects, don't add an attribute
tires
.
Attributes and Methods in a Class Diagram
542
543
A
DVANCED
T
OPIC
12.2: Multiplicities
Some designers like to write multiplicities at the end(s) of an aggregation
relationship to denote how many objects are aggregated. The notations for the
most common multiplicities are:
ȗ
any number (zero or more):
*
ȗ
one or more:
1..*
ȗ
zero or one:
0..1
ȗ
exactly one:
1
The figure below shows that a customer has one or more bank accounts.
An Aggregation Relationship with Multiplicities
