SQLF - A RELATIONAL DATABASE LANGUAGE FOR FUZZY QUERYING

An important issue in extending database management systems functionalities is to allow the expression of imprecise queries to make these systems able to satisfy user needs more closely. This paper deals with imprecise querying of regular relational databases. The basic idea is to extend an existing query language, namely SQL. In this context, two important points must be considered. The one concerns the integration in the extended language of many propositions that have been made elsewhere, in particular those concerning fuzzy aggregation operators. The second point is to know whether the equivalences which are valid in SQL still hold in the extended language. Both these topics are investigated in this paper.