Event-condition-action rules; Reactive rules; Triggers
An ECA rule has three parts: an event, a condition, and an action. The semantics of an ECA rule are when the event has been detected, evaluate the condition, and if the condition is satisfied, execute the action.
ECA rules are used within active databases for supporting reactive behavior and were first proposed in the HiPAC project .
The semantics of an ECA rule is straightforward: when an event is detected, evaluate the condition, and if the condition is true, then execute the action. There are a number of reasons why the reactive behavior is abstracted to three different parts :
First of all, events, conditions, and actions have different roles. An event specifies when to trigger a rule, a condition specifies what to check, and an action specifies what to execute in response to the event. Thus, the semantics of an ECA rule is clean and avoids ad hoc mixing of events,...
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