Extending ER/EER concepts towards fuzzy conceptual data modeling

Entity relational (ER) and enhanced ER (EER) models play an important role in conceptual data modeling. This paper presents fuzzy extensions to several major ER/EER concepts so that uncertainty and imprecision in data and semantics can be represented and dealt with at a conceptual level. First, fuzzy extensions to basic ER/EER concepts such as superclass/subclass, generalization/specialization, and shared subclass/category are discussed. Next, the attribute inheritance is investigated in a fuzzy context, including multiple inheritance, selective inheritance, and the inheritance for derived attributes. Finally, certain constraints on relationships are explored in terms of the inheritance constraint, the participation constraint, and the cardinality constraint.