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Journals Conferences Reports
Hofstede, A.H.M. ter and Proper, H.A. and Weide, Th.P. van der, Formal definition of a conceptual language for the description and manipulation of information models. Information Systems, Nr: 7, Vol: 18, Pages: 489-523, October, 1993
Conceptual data modelling techniques aim at the representation of data at a high level of abstraction. This implies that conceptual data modelling techniques should not only be capable of naturally representing complex structures, but also the rules (constraints) that must hold for these structures. Contemporary data modelling techniques however, do not provide a language, which on the one hand has a formal semantics and on the other hand leads to natural looking expressions, for formulating these constraints. In this paper such a language is defined for an existing data modelling technique (PSM), which is a generalisation of object-role models (such as ER or NIAM). In this language not only constraints, but also queries and updates can be expressed on a conceptual level.
Hofstede, A.H.M. ter and Weide, Th.P. van der, Expressiveness in conceptual data modelling. Data & Knowledge Engineering, Nr: 1, Vol: 10, Pages: 65-100, February, 1993
Conceptual data modelling techniques aim at the representation of data at a high level of abstraction. The Conceptualisation Principle states that only those aspects are to be represented that deal with the meaning of the Universe of Discourse. Conventional conceptual data modelling techniques, as e.g. ER or NIAM, have to violate the Conceptualisation Principle when dealing with objects with a complex structure. In order to represent these objects conceptually irrelevant choices have to made. It is even worse: sometimes the Universe of Discourse has to be adapted to suit the modelling technique. These objects typically occur in domains as metamodelling, hypermedia and CAD/CAM. In this paper extensions to an existing data modelling technique (NIAM) will be discussed and formally defined, that make it possible to naturally represent objects with complex structures without having to violate the Conceptualisation Principle. These extensions will be motivated from a practical point of view by examples and from a theoretical point of view by a comparison with the expressive power of formal set theory and grammar theory.
Journals Conferences Reports
Burgers, C.A.J. and Proper, H.A. and Weide, Th.P. van der, Organising an Information System as Stratified Hypermedia. Proceedings of the Computing Science in the Netherlands Conference, Edited by: H.A. Wijshoff. Pages: 109-120, November, 1993
In this paper we investigate a relation between modern hypertext approaches and conventional data modelling techniques, such as PSM. This relation provides us with the mechanism of query by navigation, in order to facilitate the query formulation problem.
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Collignon, M.A. and Weide, Th.P. van der, An Information Analysis Method Based on PSM. Proceedings of NIAM-ISDM, Edited by: G.M. Nijssen. September, NIAM-GUIDE, 1993
This paper is a step towards a more formal approach to the information analysis method NIAM. It also provides a formalisation and some extensions to the modelling techniques used in NIAM
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Proper, H.A. and Weide, Th.P. van der, Towards a General Theory for the Evolution of Application Models. Proceedings of the Fourth Australian Database Conference, Edited by: M.E. Orlowska, and M.P. Papazoglou. Advances in Database Research, Pages: 346-362, February, World Scientific, Melbourne, Victoria, Australia, 1993, ISBN 981021331X
In this article we focus on evolving information systems. First a delimitation of the concept of evolution is discussed. The main result is a first attempt to a general theory for such evolution. In this theory, the underlying data model is a parameter, making the theory applicable for a wide range of modelling techniques.
Journals Conferences Reports
Peters, A.Th. and Eekelen, M.C.J.D. van and Plasmeijer, M.J. and Weide, Th.P. van der, A CASE-tool for the development of Information Systems implemented in a pure functional language. Technical report, Computing Science Institute, Nijmegen, The Netherlands, EU, 1993
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Bommel, P. van and Lucasius, C.B. and Weide, Th.P. van der, Genetic Algorithms for Optimal Database Design. Technical report: CSI-R9301, February, Radboud University Nijmegen, 1993
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