Incorporating Fuzzy Inference into Database Triggers

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 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. Espoo, November 1996