Generating active rules from high-level specifications

Abstract

Rules have been proposed as a mechanism for providing active behaviour in databases; some of the most popular uses being the support of integrity constraints, the maintenance of materialised views and security enforcement. However, the difficulty of defining rules discourages end users from taking full advantage of their functionality. What is required is a mechanism for the automatic translation of high-level specifications of behaviour into equivalent sets of rules. In addition to making rules easier and safer to use, such a facility makes the specification of behaviour explicit — rather than having it embedded within rule code — and allows it to be used by other parts of the database management system. For example, if constraints are specified declaratively, they can be used for other purposes such as semantic query optimisation. This paper describes how rules can be generated automatically from declarative specifications of integrity constraints and the operational semantics of relationships. This is borne out by an implementation in ADAM, an object-oriented database written in Prolog.