Composite event support in an active database

An intelligent or active database system is able to provide support to engineering applications, which require both data and rules to be managed. CLOSE is an active database, which integrates an object-oriented database, ObjectStore with an expert system, CLIPS. Engineering applications require a broad range of composite events, which are combinations of primitive events such as time events, method events and absolute events. This paper focuses on the design and implementation of composite events. Detection of these composite events is supported by a Rule Manager. The data structures used and the mechanism for composite event detection is described. Example applications are also presented in order to highlight the usefulness of composite events.