Active databases utilize Event-Condition-Action rules to provide active capability to the underlying system. An event was initially defined to be an instantaneous, atomic occurrence of interest and the time of occurrence of the last event in an event expression was used as the time of occurrence for an entire event expression (detection-based semantics), rather than the interval over which an e...

This paper examines an emerging technology known as active databases. The focus is on issues which need to be considered in their development and the way they have been addressed in currently implemented systems. We examine what deenes active behavior, why it is useful, the semantics of its spec-iication and choices that have to be made when realising it in an actual system. We see that a multi...

This paper proposes an approach to building event services for active database applications. It introduces dimensions to characterize distributed event deenition, detection, production and notiication. The core of our approach is a parametric event service called QUET-ZAL that has three interfaces, each of them implementing the given dimensions as parameters. Therefore, diierent event (detectio...

A benchmark for active database management systems is described. We are particularly interested in performance tests that help to identify performant and inefficient components. Active functionality that is relevant with respect to performance is identified, and a series of tests is designed that measure the efficiency of the performance-critical components. Results obtained from running the be...

The powerful functionality that active mechanisms add to database management systems presents, besides many advantages, a number of problems related to the control of their behavior. This paper deals with one of these problems: the termination of rule execution. We explain the termination aspect and the aim of termination analysis. Then, we present our approach for investigating the termination...

This position paper considers several existing relational database rule languages with a focus on exploring the fundamental di erences between deductive and active databases. We nd that deductive and active databases do not form two discernible classes, but rather they delineate two ends of a spectrum of database rule languages. We claim that this spectrum also corresponds to a notion of abstra...

This paper examines Active Databases and Agent Systems, comparing their purpose, structure, functionality, and implementation. Our presentation is aimed primarily at an audience familiar with active database technology. We show that they draw upon very similar paradigms in their quest to supply reactivity. This presents opportunities for migration of techniques and formalisms between the two elds.

This paper examines Active Databases and Agent Systems, comparing their purpose, structure, functionality, and implementation. Our presentation is aimed primarily at an audience familiar with active database technology. We show that they draw upon very similar paradigms in their quest to supply reactivity. This presents opportunities for migration of techniques and formalisms between the two elds.