In the similarity relation based fuzzy database approach, query results are allowed to contain not only data that exactly satisfy the search conditions but also data that are similar to these data. For this reason, the attribute domains have to be equipped with a similarity relation. (A similarity relation is a fuzzy binary relation whose membership function expresses the similarity degree between the pairs of the domain elements.)
Published in Chapter:
An Overview of Fuzzy Approaches to Flexible Database Querying
Slawomir Zadrozny (Polish Academy of Sciences, Poland), Guy de Tré (Ghent University, Belgium), Rita de Caluwe (Ghent University, Belgium), and Janusz Kacprzyk (Polish Academy of Sciences, Poland)
Copyright: © 2008
|Pages: 21
DOI: 10.4018/978-1-59904-853-6.ch002
Abstract
In reality, a lot of information is available only in an imperfect form. This might be due to imprecision, vagueness, uncertainty, incompleteness, or ambiguities. Traditional database systems can only adequately cope with perfect data. Among others, fuzzy set theory has been applied to deal with imperfections of data in a more natural way and to enhance the accessibility of databases. In this chapter, we give an overview of main trends in the research on flexible querying techniques that are based on fuzzy set theory. Both querying techniques for traditional databases as well as querying techniques for fuzzy databases are described. The discussion comprises both the relational and the object-oriented database modeling approaches.