Incorporating fuzzy inference into database triggers
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by Tarik Bouaziz and Antoni Wolski 

Technical Report TTE1-2-96, VTT Information Technology, Espoo, Finland, 
November 1996, 18 pp.

Abstract

Triggers (active rules) bring domain-specific reactive behavior to
databases. Traditional Event-Condition-Action triggers use only crisp
concepts. In this paper, fuzzy triggers are proposed whereby
approximate reasoning may be integrated with a traditional crisp
database. The new approach paves the way for the intuitive expression 
of application semantics of imprecise nature in database-bound
applications. Several levels of applying fuzzy concepts to triggers
are proposed. Fuzzy propositions may be incorporated, as elementary 
predicates, in Boolean trigger conditions. A significant improvement 
of the condition expression power is achieved by encapsulating a set 
of fuzzy rules into a Boolean-valued function called the rule set 
function. Subsequently, actions are expressed also in fuzzy terms, 
in a trigger model. Examples are provided to illustrate how fuzzy 
triggers can be applied to a real-life drive control system 
in an industrial installation.