The ORM Foundation

Abstract. A conceptual schema of an information system specifies the fact structures of interest as well as related business rules that are either constraints or derivation rules. Constraints restrict the possible or permitted states or state transitions, while derivation rules enable some facts to be derived from others. Graphical languages are commonly used to specify conceptual schemas, but often need to be supplemented by more expressive textual languages to capture additional business rules, as well as conceptual queries that enable conceptual models to be queried directly. This paper describes research to provide a role calculus to underpin textual languages for Object-Role Modeling (ORM), to enable business rules and queries to be formulated in a language intelligible to business users. The role-based nature of this calculus, which exploits the attribute-free nature of ORM, appears to offer significant advantages over other proposed approaches, especially in the area of semantic stability.