The concept of a trigger is central to any active database. upon the cocurrence of a trigger event, the trigger is '' fired '', i.e, the trigger action is executed. we describe a model and a language for speciying basic and composite trigger events in the context of an object-oriented database. the specified events can be detected efficiently using finite automata.
we integrate our model with O++, the database programming language for the ode object database being developed at AT&AT bell labs. we propose a new event-action model, which folds into the event specification the condition part of the well-known event-condidition-action model and avoids the multiple coupling modes between the event, condition, and action trigger components.
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