Fact-based modelling; ORM method; Paired transactions; REA ontology

Paired transactions or paired transfers have their origin in accountancy systems. Resource-Event-Agent (REA) ontology uses paired transactions as a basic building block for business process modelling. A business process (REA model) is composed of two kinds of paired transactions which stand for provide (give) and receive (take) transactions (transfers). The REA core pattern which comes from double-booking entry, constitutes the basic structure from which the REA model is further extended. The REA model was previously depicted by ER diagrams, and later by UML class diagrams. However, neither of these diagrams were designed to capture conceptual models which are more precise and comprehensible for domain experts, and easy to modify. ORM (Object Role Modeling) is a Fact-Based Modeling methodology that represents an approach to conceptual modelling that fulfils the requirements. The article presents fact-based models of paired transactions corresponding to the REA core pattern and REA exchange model. These models were created and verified by NORMA (Natural ORM Architect) and provide both semantic stability and semantic relevance, which is necessary for further incorporating the REA modeling approach into fact-based modeling methodologies of business processes.