An EER Prototyping Environment and its Implemetation in a Datalog Language

In this paper we present an approach to represent schema information, application data and integrity constraints as a datalog program. The schema information is supplied as an enhanced entity relationship (EER) model which is transformed by a one-to-one mapping into a set of ground facts. The application data corresponding to the schema is represented by ground facts as well by using a single predicate named observation. In order to check whether the application data conforms to the given schema, a set of integrity rules is defined which expresses the dependencies (mostly functional and inclusion dependencies) implied by the EER model. In order to check whether the application EER model is a valid EER model a meta EER model is defined. Any application EER diagram appears as an instance of the meta EER diagram which can be specified using the same application data representation as above. This way a single set of the integrity rules can be used to check the conformance between the application data and the application EER diagram, the meta EER diagram and the application EER diagram. Since the representation of the meta EER diagram is an instance of the meta EER diagram, the validity of the meta EER diagram is checked as well. The resulting logic program is composed of the application data, the application schema, the meta schema, a general set of constraints plus optionally additional application specific constraints and deduction rules.