27.6. Derived Elements
A derived element can be determined from others. Attributes and associations are the most common derived elements. When should derived elements be shown?
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Avoid showing derived elements in a diagram, since they add complexity without new information. However, add a derived element when it is prominent in the terminology, and excluding it impairs comprehension. |
For example, a Sale total can be derived from SalesLineItem and ProductSpecification information (see Figure 27.12). In the UML, it is shown with a “/” preceding the element name.
Figure 27.12. Derived attribute.
As another example, a SalesLineItem quantity is actually ...
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