Basic Principles and Background
2.2.5 Diagrams as Views
Each particular UML diagram corresponds to one view of a model of a system.
Depending on the type of diagram used, different aspects are either emphasized or
omitted. All the different views combined result in a good model of a system. Most of the
UML diagrams are
graphs (as shown in Figure 2.5), implying that they consist of
elements that are connected through lines:
Figure 2.5 Diagram as graphs
To read diagrams, you have to know what types of elements and lines are allowed and
what they mean. We'll explain this for the diagrams we use in the following chapters.
Even
computer-aided software engineering (CASE) tools treat UML diagrams as
views. They use a
database in which the information about the model is stored. Each
diagram shows—as a view—a part of that information. In this way, the CASE tool helps
to preserve the consistency of each view. If, for example, the name of a class is changed
in a class diagram, the statechart diagram of that class is automatically updated:
Figure 2.6 CASE tool as database
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