Design of active rule applications: Issues and approaches

The use of objects and rules in modern database systems is the main focus of the IDEA Esprit Project. In particular, it inspires the IDEA Methodology, a comprehensive and systematic approach to the design of database applications which use both deductive and active rules. The IDEA Methodology reconciles deductive and active rules by assigning them the role of expressing knowledge about the application domain, either with a purely declarative style, or with a more procedural style. Although active rules are inherently procedural, in many cases they can be automatically or semi-automatically generated from declarative specifications. This paper is focused on active rules, the main research interest of the Politecnico in the IDEA project. We concentrate on active rule analysis, design, and prototyping as developed in the context of the IDEA Methodology. Given that active rules are quite complex to understand and manage, we present several abstractions and techniques which enable their safe specification, in particular with respect to collective desired properties (such as termination). We also informally introduce the notion of modularization, that enables the partitioning of complex rule sets into modules which exhibit nice interaction properties. Research presented in this paper is supported by Esprit project P6333 IDEA, and by ENEL contract VDS 1/94: Integrity Constraint Management