Logical Composite Events - General Event Matching in ECA-Rules

Active database systems are designed to monitor database activities. An active system will react to events, taking necessary action as defined by given rules. The traditional approach uses event-condition-action rules (ECA-rules). One variation is to use logical events and EA-rules. Each of these approaches can be shown to have modelling and/or maintenance problems. This report investigates the semantic problems in ECA-rules and demonstrates a solution in an object-oriented environment by introducing logical events into the ECA-rules paradigm. This new approach extends the ECA formalism with logical events into an event-condition-condition-action (EC-CA) model.

The thesis outlines the semantic benefits of EC-CA as well as impacts on efficiency. It defines logical events based upon primitive and composite events and a form of logical primitive event condition on the event-context for efficiency. The thesis reports on an integration of the feature into the prototype system ACOOD (version 2). It also identifies some issues of event matching. Implementation issues are analysed, as well as their impact on the proposals.