Fuzzy Aggregations and Fuzzy Specializations in Eindhoven Fuzzy EER Model

Abstract

Some approaches about fuzzy ER/EER model have been published recently. Few of these works study how to relax constraints and other aspects expressed in the model. In this chapter our aim is to relax some semantic aspects which have not been studied in previous works and to extend the EER model with fuzzy capabilities. We use fuzzy quantifiers and fuzzy degrees which have been widely studied in the context of fuzzy sets and fuzzy query systems for databases. We will also examine the representation of these new features in an EER model and their practical repercussions. The studied extensions are: fuzzy aggregations and fuzzy aspects on specializations, such as fuzzy degrees, fuzzy completeness constraint, fuzzy cardinality constraint on overlapping specializations, fuzzy disjointed or overlapping constraints, fuzzy attribute defined specializations, fuzzy constraints in union types or categories and fuzzy constraints in shared subclasses (or intersection types). All these fuzzy extensions have a new meaning and offer greater expressiveness in conceptual design.