Entity Types Derived by Symbol-Generating Rules

We review the definition of entity types derived by symbolgenerating rules. These types appear frequently in conceptual schemas. However, up to now they have received very little attention in the field of conceptual modeling of information systems. Most conceptual modeling languages, like the UML and ORM, do not allow their formal definition. In this paper, we propose a new method for the definition of entity types derived by symbol-generating rules. Our method is based on the fact that these types can always be expressed as the result of the reification of a derived relationship type. Many languages, like the UML and ORM, allow defining derived relationship types and, at the same time, provide support for reification. Using our method, these languages can directly deal with those derived entity types.