Conceptual modeling is one of the most important activities in the modeling phase of information systems development most commonly presented by entity-relationship data model. This paper presents a system for entity-relationship data model semantic evaluation that is based on comparing ontology with data model elements. This approach is based on domain ontology and data model formalization at predicate calculus form that is suitable for reasoning. A set of reasoning rules for ontology to data model mapping was defined. The whole process is empirically verified and confirmed. For this purpose it has been developed a software tool for ontology and data model transformation to predicate logic form and then to a set of Prolog-like clauses. After integration of these sets of clauses and rules, a Prolog-system was used for reasoning in order to quantitatively express the quality of data model with appropriate metric.