Geoffrey J. Kennedy
Computer and Information Science
University of Otago, Dunedin, New Zealand
A systematic investigation of entity-relationship diagrams results in the identification and characterisation of three elementary data structures into which any diagram can be decomposed. Recognition of these structures is shown to provide a useful analytical and diagnostic tool for data modelling and an example of their application is given. The possibility is discussed of using elementary structure counts as the basis for a metric for system development effort estimation. Such a metric could be applied earlier in the development cycle than others currently in use. Empirical results so far obtained have not been useful, due to difficulties encountered in obtaining reliable effort data.
Keywords: Data modelling, Design Tools and Techniques, Entity-relationship model, Metrics