An entity-relationship modeling approach to IDEF0 syntax

The development of an entity-relationship (ER) model of the IDEF ₀ methodology for software development is described. It is hypothesized that a given IDEF₀ diagram is actually just a graphic representation of a more fundamental underlying model, which could be represented by any number of diagrams. Thus, two models are defined: the abstract model, which is the underlying fundamental model, and the drawing model which defines one of many possible graphical representations of the abstract model. There is a one-to-many mapping between an abstract model and the infinitely many drawings that could represent it. Each of these models is developed using ER diagrams, and the relationship between the two models is defined. To facilitate the use of these models in developing computer-aided software engineering (CASE) tools, an object-oriented design of these ER models was developed, and packages were coded in Ada to allow the data for IDEF₀ diagrams to be stored and manipulated in memory, as well as stored to and loaded from disk