Conceptual Entity-Relationship Model: Beneath the Simplicity and Staticity

This paper deals with the issue of conceptual models’ role in capturing semantics and aligning them to serve the remaining development phases of systems design. Specifically, the entity-relationship (ER) model is selected as an example of conceptual representation that serves this purpose in building relational database systems. It is claimed that ER diagrams provide a solid basis for subsequent technical implementation. The ER model appeal relies on its simplicity and its benefit in clarifying the requirements for databases. It is also claimed that the ER model has achieved a good equilibrium between expressive power on one hand and simplicity on the other. Nevertheless, some researchers have observed that this reduction of complexity is accompanied by oversimplification and overlooking dynamism. Accordingly, complaints have risen about the lack of direct compatibility between ER modeling and relational model. Substantial evidence exists showing that designers often provide incomplete, inaccurate, or inconsistent representations of domain features in the ER conceptual models they prepare. This paper is an attempt to explore what is beneath this static ER simplicity and its role as a base for subsequent technical implementation. In this undertaking, we use thinging machines (TMs), where modeling is constructed upon a single notion thimac (thing/machine). Thimac constituents are formed from the makeup of five actions, create, process, release, transfer, and receive—that inject dynamism alongside with structure. The ER’s entities, attributes, and relationship are modeled as thimacs. Accordingly, in this paper, ER examples are remodeled in TM while identifying TM portions that correspond to ER components. The resulting TM model insets actions into entities, attributes and relationships. In this case, relationships are the products of creating linking thimacs plus the logic of constructing them. Based on such static/dynamic TM representation, the modeler can produce any level of simplification, including the original ER model. In conclusion, results indicated that the TM models facilitate multilevel simplicity and viable direct compatibility with the relational database model.