An algebraic approach to static analysis of active database rules

Abstract

Rules in active database systems can be very difficult to program due to the unstructured and unpredictable nature of rule processing. We provide static analysis techniques for predicting whether a given rule set is guaranteed to terminate and whether rule execution is confluent (guaranteed to have a unique final state). Our methods are based on previous techniques for analyzing rules in active database systems. We improve considerably on the previous techniques by providing analysis criteria that are much less conservative: our methods often determine that a rule set will terminate or is confluent when previous methods could not make this determination. Our improved analysis is based on a "propagation" algorithm, which uses an extended relational algebra to accurately determine when the action of one rule can affect the condition of another, and determine when rule actions commute. We consider both condition-action rules and event-condition-action rules, making our approach widely applicable to relational active database rule languages and to the trigger language in the SQL:1999 standard.

Verification of Business Rules Programs

“…This approach leads to using first-order logic structures as we do. A formalization of production systems with situation calculus is given by [BL07], while [BW94] represents active rules in databases by means of an extended relational algebra.…”

“…Several approaches to the verification of confluence and termination in active databases are reviewed in [BW94]. Among them, [KU94] reduces eventcondition-action rules to conditional term rewriting, and [HH91] restricts the rule language to guarantee confluence.…”

“…Among them, [KU94] reduces eventcondition-action rules to conditional term rewriting, and [HH91] restricts the rule language to guarantee confluence. [BW94] itself proposes an approach based on an extension of the relational algebra. On the other hand, [LL98] focuses on the termination problem in active databases.…”

Design issues for general-purpose adaptive hypermedia systems

“…ECA and CA rules have been studied extensively in the context of active databases [1,2]. ECA rules consist of three "independent" parts: an event, a condition and an action.…”

Output Constraints in Multimedia Database Systems

“…ECA-Rules can activate each other, this can lead to a not terminated situation during the execution of ECA-Rules. Some work has been done dealing with this termination problem [BW00]. Another problem occurs when a set of different ECARules must be executed on a certain event.…”