Formalised conceptual models as a foundation of information systems development

Abstract

The more application semantics are added to a conceptual model, the greater the portion of the respective application system can be generated automatically. To allow for an automatic generation, additional type-level semantics have to be specified formally, and a large number of object-level semantics have to be derived from tiffs formal model. Form existential dependencies, existence implications, and derivation relationships, all abstraction relationships and non-abstracting derivation relationships between object types can be constructed. Their formalisation leads to three predicates that represent direct dependencies within the conceptual model. By applying three basic production rules to these predicates, the relational closure of all indirect dependencies throughout the model can be derived formally. Based on a formalisation of elementary insert, delete, and update operations, indirect dependencies are used to identify all objects throughout the system that are affected by a data manipulation. Since the set of objects that are affected by a manipulation can be derived formally, it is possible to automatically generate database triggers that implement these object-level semantics. The generation process is presented, and examples from a simplified conceptual model and procedurally extended data model of a production planning system are given. In conceptual modeling, the proposed model extensions represent important invariant properties that are consistently specified together with structural model elements. Not only tables and static integrity constraints can be automatically generated to implement structural model elements, but also data manipulation propagation triggers can be generated to implement invariant properties. Therefore, a tight integration of structural and important behavioral aspects is provided in information system design as well as implementation. Hence, formalised extended conceptual models can be regarded as a foundation of integrated information systems development.