An approach to functional dependencies in fuzzy databases

This paper deals with the so-called fuzzy databases which contain imprecise information. More precisely, it deals with the extension of the notion of a functional dependency when data involved in this type of property are possibly imprecise. The idea is to consider a specific kind of fuzzy functional dependency, which is a very natural extension of a usual functional dependency. In this context, the presence of a functional dependency may cause some data replication and the interest of a decomposition is studied from several points of view: information preservation (or schema equivalence), impact on the procedure for maintaining the validity of the functional dependency when updates are performed, and expression of queries on the initial relation and on the relations issued from the decomposition.