UML can be used to model a business, prior to automating it with computers. The same basic UML syntax is used, however, a number of new symbols are added, in order to make the diagrams more relevant to the business process world. A commonly-used set of these symbols is available in current versions of Rational Rose.
The most commonly used UML extensions for web applications were developed by Jim Conallen. You can access his own website to learn more about them by following the link. These symbols are also available in current versions of Rational Rose.
UML is designed to be extended in this way. Extensions to the syntax are created by adding 'stereotypes' to a model element. The stereotype creates a new model element from an existing one with an extended, user-defined meaning. User defined symbols, which replace the original UML symbol for the model element, can then be assigned to the stereotype. UML itself uses this mechanism, so it is important to know what stereotypes are predefined in UML in order not to clash with them when creating new ones.
Stereotypes allow the UML syntax to be used to model anything.
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