Condition using fuzzy values and/or fuzzy comparators, whose truth is fuzzy. The fuzzy values may be fuzzy attributes or fuzzy constants, like linguistic labels or “approximately 8” (expressed by #8 in FSQL). Fuzzy comparators express fuzzy relations between two values, for example, “approximately equal,” “fuzzy greater than,” “much greater than,” and so on. The expression of preferences may be considered another kind of fuzzy condition. The fulfillment of one fuzzy condition is usually a value in the interval [0,1] giving a fuzzy fulfillment degree for each fuzzy condition.
Published in Chapter:
FSQL and SQLf: Towards a Standard in Fuzzy Databases
Angélica Urrutia (Universidad Católica del Maule, Chile), Leonid Tineo (Universidad Simón Bolivar, Venezuela), and Claudia Gonzalez (Universidad Simón Bolivar, Venezuela)
Copyright: © 2008
|Pages: 29
DOI: 10.4018/978-1-59904-853-6.ch011
Abstract
Actually, FSQL and SQLf are the main fuzzy logic based proposed extensions to SQL. It would be very interesting to integrate them with a standard for fuzzy databases. The issue is what to take from one or other proposal. In this chapter, we analyze FSQL and SQLf making a comparison in several ways: approach direction, fuzzy components, system architecture, satisfaction degree, evaluation mechanisms, and experimental performance. We observe that there are powerful and interesting features in both proposals that could be mixed in a unified language for fuzzy relational databases.