Explicit Event

Definition

In active databases, an explicit event is explicitly specified in the ECA rule definition.

Key Points

ECA rules were developed as an optimization of condition action rules. The performance of rule evaluation was improved by allowing, or even requiring, explicit definition of when rules should be triggered in the form of events. For example, (ON update_Afollowed_by update_BIF A = 5∧ B = 3 DO action) is a rule specification that is triggered by the explicit event update_Afollowed_by update_B (i.e., a sequence of updates).

Cross-References

• Atomic Event

• Composite Event

• ECA Rules

• Event Detection

• Event Specification

• Implicit Event