SQLf Query Functionality on Top of a Regular Relational Database Management System

Abstract

This paper is mainly concerned with the extension of database management systems querying capabilities, so that users may address queries involving preferences and get discriminated answers. The use of flexible (gradual) predicates interpreted in the framework of the fuzzy set theory is advocated for defining a query language, called SQLf. This language enlarges the functionalities offered by SQL and it is considered here from a query processing point of view.