The PFSQL Query Execution Process

Abstract

Usable implementations of fuzzy relational database systems are very rare considering the long time of research on the subject. The existing solutions are usually either obsolete or related to a speci c application. The research group that authors belong to aims at producing a general system capable of using priority fuzzy logic with databases. The system consists of a fuzzy extension of a relational model, a fuzzy query language PFSQL for this data model, a CASE tool that allows easy creation of fuzzy relational database schemas, and an extension to JDBC driver that incorporates possibilities to use PFSQL queries. In this paper we present details of the implementation of the PFSQL interpreter. We describe a model that we devised and point out decisions we made and tools we used in the implementation process. The result is a working implementation of the rst priority fuzzy logic extension of the SQL language.