Fuzzy functional dependency and its application to approximate data querying

Reviews a new definition of fuzzy functional dependency based on conditional probability and its application to approximate data reduction related to the operation of projection in classical relational databases in order to construct fuzzy integrity constraints. We introduce the concept of partial fuzzy functional dependency, which expresses the fact that a given attribute X does not determine Y completely, but in the partial area of X it might determine Y. Finally, we discuss another application of fuzzy functional dependency in constructing fuzzy query relations for data querying and approximate joins of two or more fuzzy query relations in the framework of an extended query system.