The Entity – Relationship Model (ER) is an abstract model that describes the data in graphic symbols as entities, relationships and attributes. It is used during the conceptual design of a database to display it in a form understandable to all, which will help communication between database designers and users for the successful development thereof. The Extended Entity – Relationship Model (EER) enriches the above model with inheritance relationships between entities such as generalization, specialization and union. The next step is the logical design, namely the implementation of the above model using the chosen Database Management System (DBMS).

Application ER2SQL is an entity – relationship diagram drawing tool that fully covers the symbols and concepts of EER, adopting the Chen notation and (Min, Max) notation. Resulting diagrams are stored in a new, open and well-defined XML standard, in which the objects are described semantically and not as simple shapes. Also, it is capable for the automatic conversion of the above diagram to relational and object-relational schemas by creating SQL-99 and PostgreSQL code respectively, fully automating the process of creating the logical model of the database. Finally, there is the ability to detect possible errors in the design, enhancing the educational component of the application.

Michael Voultsidis (wultz1@gmail.com)