Entity Modelling

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

Examples and applications of the notation of Tutorial One

Before we go ahead and describe the use of entity models in relation to information systems we give some illustrative examples.

Modelling a scenario that might be new to us we have to start with an analysis of the descriptions that we are given and it has been noted in the past that nouns used in the description are candidates for entity types within the model. Our first example shows that the situation might be more subtle and that a single noun may have many entity types vying to be so named.

Entity-relationship modelling can be used to model grammars and we illustrate this here in an example based on a phase structure grammar for simple english sentences. Next we consider some ways of modelling directed graphs and, finally, we reproduce the following
  • the khipu. If we want to understand data modelling and messaging from first principles then we need study the quipu and try and formulate the questions that it asks of us.