Event condition action (ECA) is a short-cut for referring to the structure of active rules in event driven architecture and active database systems. Such a rule traditionally consisted of three parts: * The event part specifies the signal that triggers the invocation of the rule * The condition part is a logical test that, if satisfied or evaluates to true, causes the action to be carried out * The action part consists of updates or invocations on the local data ECA rules can also be used in rule engines that use variants of the Rete algorithm for rule processing.