A generic model for 3-dimensional conceptual modelling

摘要

This article discusses two highly intertwined issues. Firstly, we discuss the lack of top-down abstraction mechanisms in data modelling techniques; i.e. abstraction techniques that are fully integrated into the modelling technique and methodology and not just a ‘post-modelling process’ add on. Secondly, we are concerned with the integration of object-oriented modelling techniques and traditional data modelling techniques.We start by discussing the pragmatics and motivations behind these issues. Then, a formalisation of (the syntax and semantics of) a data modelling technique is presented that is a generalisation of (E)ER and ORM, and also adheres to the requirements of an object-oriented technique as laid down in the object-oriented manifesto. The result of this exercise is the so-called CDM Kernel. Furthermore, we briefly show how (E)ER, ORM and object-oriented views can be derived from models in the CDM Kernel. This effectively means that the CDM Kernel equates (E)ER, ORM and (some) object-oriented models.Finally, we briefly discuss some practical issues on the use of the facilities offered by the CDM Kernel in terms of modelling practice and tool support. A generalised conceptual modelling kernel will be very beneficial in the context of CASE Tool and in the context of federated database (information) systems.