Rules Rules are distinct from the interrelations in that they do not increase what
information can be stored, but instead they prevent certain kinds of information
content from being stored, since it is considered illegal or undesirable in the domain.
For many metamodelers, there is a considerable temptation to build many rules to
protect the modelers. Now is not the time for that. Indeed, experience has shown that
the number of rules in a modeling language tends to decrease over time. Modelers ?¬?nd
that the tool prevents them from creating a certain structure, but they have a clear idea
of what that structure would mean. The rule is thus removed from the modeling
language, and handling for that situation is added to the generator, making the DSM
solution simultaneously both simpler and more powerful.
Notation Some notation will be necessary to allowtheDSMteam and modelers to
work sensibly with the developing modeling language. For now, the notation should
concentrate on presenting the most relevant data content of each concept in a sensible
and balanced fashion. The symbols for different concepts should be easily
342 DSM DEFINITION PROCESS
distinguishable, with central concepts or relationships being more visible. With a
good DSM environment, it should be quick and easy to achieve this with simple
variations in shape, line and ?¬?ll colors, and line width.
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