| The Entity Relationship model (ER) and its extensions (EER) are popular models for the conceptual design step in the database design process. Under the traditional approach to database design the structure of the database is modeled using the EER model. Dynamic information from the Universe of Discourse (UoD), for example, data changing operations like insert, delete, and update are not represented at this conceptual level. The issues concerning the dynamics (data manipulation) of the information system are addressed only during the implementation stage. Any inconsistencies between the static and dynamic components is not directly assessed until implementation.; We view the representation of dynamic data changing aspects as a necessary component in the conceptual modeling phase. We present a graphical conceptual model based on the EER model and Petri net concepts which allows for the simultaneous modeling and design of structural and behavioral aspects of a database application. |
