Luigi Portinale and Andrea Verrua, Universita' del Piemonte Orientale, Italy
The use of database technologies for implementing CBR techniques is attracting a lot of attention for several reasons. First, the possibility of using standard DBMS for storing and representing cases significantly reduces the effort needed to develop a CBR system; in fact, data of interest are usually already stored into relational databases and used for different purposes as well. Finally, the use of standard query languages, like SQL, may facilitate the introduction of a casebased system into the real-world, by putting retrieval on the same ground of normal database queries. Unfortunately, SQL is not able to deal with queries like those needed in a CBR system, so different approaches have been tried, in order to build retrieval engines able to exploit, at the lower level, standard SQL. In this paper, we present a proposal where case retrieval is implemented by using a fuzzy version of SQL. In the presented approach a fuzzy notion of similarity is adopted and an extended version of SQL, dealing with fuzzy predicates, is introduced. A case-based system prototype exploiting Fuzzy-SQL as a retrieval engine is then presented.