For this reason, all of the commonly used systems of notation fundamentally are convertible one to another. The major differences among them are aesthetic, although some make distinctions that others do not, and some do not have symbols to represent all situations. The first is syntactic , about the symbols to be used. These conventions are the primary focus of this article. The second defines the organization of model diagrams.
Positional conventions dictate how entities are laid out.
These will be discussed at the end of the article. And finally, there are conventions about how the meaning of a model may be conveyed. Semantic conventions describe standard ways for representing common business situations. These three sets of conventions are, in principle, completely independent of each other. Given any of the syntactic conventions described here, you can follow any of the available positional or semantic conventions.