Högskolan i Skövde

Current prototype Active Object-Oriented database systems introduce powerful event and rule specification languages. We contend that this is not in general done in a uniform and integral manner. We present a modified design for an ACtive Object-Oriented DBMS (ACOOD) currently under development at the University of Skovde. The design emphasises the key concepts being investigated, namely Events and Rules as 1st Class (ER1C). It is important because it addresses the key issue of inheritance, something not prominent in current prototype systems with a fully developed event specification system. Key features in the design are that it has a unifying concept of primitive event and of behaviour, and achieves uniformity and power with respect to inheritance. It further relates this to event specification languages for composite events, guaranteeing orthogonality of features. The paper emphasises modeling concepts, and the design is therefore of relevance to all active, object-oriented database systems. It seeks to explore the wider implications and underpinnings of current active O-O suggestions rather than enriching event and/or rule specification languages.