Entity Modelling

www.entitymodelling.org - entity modelling introduced from first principles - relational database design theory and practice - dependent type theory

Entity Modelling — An Introductory Perspective

According to Jonathan Culler1, Saussure, founding modern linguistics in the early part of the 20th century, addressed a question regarding systematically coming to terms with a complex world with a reply that included the view that

you cannot hope to attain an absolute or God-like view of things but must choose a perspective ... within this perspective objects are defined by their relations with one another rather than by essences of some kind.
This summary perfectly frames entity modelling — entity modelling takes this view to the extreme. The nub of this chapter is that entity modelling is a new spin on an ancient discipline. The subject is technical but metaphysics and the concept of concept lurk in the background and give perspective.

An entity model may simply handwave a set of concepts or it may be more detailed; sufficiently and appropriately detailed entity models, we call them physical entity models, are pretty much the same thing as Information System's data models and hence data modelling, at least as written of here, is a special case of entity modelling. We try to approach it from first principles and sometimes, take heed, this requires terminological deviation from the norm.

In this chapter we start out by making the case that an entity model provides

and that because entity modelling is a practical discipline used in engineering systems and yet is concerned with all manner of describable things it involves a Entity models cover specific areas, chosen perspectives, in the words of Culler, which in other contexts might be described as and within these perspectives the main focus of an entity model is on the
  • types of things— the deliberation of which is of course a concern with a long history.
The view of entity modelling which we present reveals a specific recurring pattern in conceptual thought which we describe in the section and in which we can recognise the philosophical concept of which is functionally reincarnated, so to speak, in the table DUAL familar to Oracle programmers. We borrow from the language of Gilbert Ryle, to argue that entity modelling is an aid to logical analysis and assists avoidance of Finally, we present some thoughts about the foundations of data modelling in and some historical notes in a section on

1 Culler, J.D.. Saussure. Fontana modern masters, Fontana Press, 1985.