Softening the object-oriented database model: imprecision, uncertainty, and fuzzy types

Object-oriented databases have proved to be a good alternative to the relational ones of Codd when dealing with applications characterized by their complexity and dynamism. A big part of the effort of researchers in the field of object-oriented databases (OODB) has been focused on the study of the addition of vagueness to this database model. There are different levels where vagueness can arise: uncertain and imprecise attribute values, fuzzy extents in classes, vague relationships between classes (including inheritance), and soft type definitions. We summarize our proposal in this area, showing how these different sources of vagueness can be managed over a traditional OODB system. We explain the new structures to be considered in order to incorporate vagueness and we use the Unified Modeling Language (UML) to make the conceptual representation of this structures clear because of its direct translation to an object-oriented model.