Design and implementation of an object-oriented rule management system for active database services

Abstract

As the information management paradigm shifts from the data management to the knowledge management, the next-generation database applications will require auto-everything technology which minimizes users`` (or applications``) intervention in the course of decision-making. One of the most potential approaches is to use active rule facilities for representing and processing knowledges specified either implicitly or explicitly within applications as well as databases. By defining and managing the rules separately from the data, a new concept of high-level data independence, i.e., knowledge independence can be achieved, by which both application and database management become relieved from the burden of frequent database changes due to the changes in application strategies and database constraints. Active rule management and processing facility on top of the traditional database management functions provide database with advanced decision-making services, making the passive database systems active. Active rules defined in an active database system specify that certain actions are to be executed automatically whenever certain events occur and specified conditions are met. There is a wide spectrum of aspects in designing and implementing rule definition and execution models in active database systems. $\It{Rule definition model}$ describes what can be specified in active rules. A good system will require a rule language that is expressive enough to describe complex events and rules and is easy to learn. $\It{Rule execution model}$ describes how the active system behaves once a set of rules are defined. In this model, the system requires a solid mechanism for detecting events, scheduling triggered rules, evaluating conditions, and executing actions. In active rule systems, user transactions and rule transactions should be integrated since rules have to be executed in the same context as the user transaction. Also, implementation of various Event-Condition-Action(E...