On the Versatility of Fuzzy Setsfor Modeling Flexible Queries

The idea of introducing preferences into queries is gaining more and more attention in the database community. After some initial works in the 1970s and 1980s, such as nearest neighbors (Friedman, Baskett, & Shustek, 1975), Deduce2 (Chang, 1982), Preferences (Lacroix & Lavency, 1987), Ares (Ichikawa & Hirakawa, 1986), and Vague (Motro, 1988), a new stream of work, including top-k queries (Bruno, Chaudhuri, & Gravano, 2002), PreferenceSQL (Kie�ling&Köstler,2002),Skyline (B�rzs�nyi, Kossmann, & Stocker, 2001), and the synthesis in Chomicki (2003), is based on the use of preferences inside user queries. Undoubtedly, this contributes to make queries (and database systems) more flexible, but it must be noticed that most (not to say all) of these approaches or systems do not call on fuzzy sets. We believe that the main advantage for founding flexible queries on fuzzy sets lies in the generality of the approach, which allows notably the combination of preferences AbstrAct