Journal of Information Technology

Document Type

Research Article


This paper begins by describing a generally accepted view of the contemporary information systems development process. This process assumes the direct derivation of a prototype from data models which have themselves been derived from a functionally decomposed representation of reality. The data models are constructed using entity-relationship modelling (ERM) and data flow diagram (DFD) techniques. The paper also considers the use of Petri net representations as structured process models of reality. These representations are a means of structuring the functional analysis of observed situations for which an information system design is required. The paper then suggests a refinement to the model just described. It examines the relationship between the ERM and DFD techniques and proposes the use of logical access mapping (LAM) as a method of synthesizing the product of these two data modelling activities. An example is used to illustrate the derivation of ERM and DFD from Petri nets. Also an example of the refined process model is given. ‘Weak links’ in this model are identified and further work towards establishing a method for formally proving data models is proposed.