14 - Reverse engineering physical schemas to logical models

Abstract

This chapter provides overview on the methodology to reverse engineer an existing database into a logical model. A physical database may be reverse engineered to either an object-role modeling (ORM) model or to a logical model. Reverse engineering to ORM enforces a stricter model that checks rules that are required for reverse engineering to a logical model. If the ORM reverse engineering process fails, the possibility exists related to the reverse engineering for database to a logical model. This process requires an open database connectivity (ODBC) connection that may already exists or can be created from within the reverse engineering wizard. A wizard is helpful to guide the reverse engineering process. If the process succeeds, the result is a logical entity relationship (ER) model corresponding either to the whole of the physical database schema or to that portion of it that is selected to reverse engineer. To reverse engineer an existing database, one should open a new instance of the Database Model Diagram solution and choose Database > Reverse Engineer from its main menu. This opens the Reverse Engineering Wizard. Import ERwin models and older VisioModeler ORM models or logical models can also be imported using the Import/Export option. To do this, one should choose Database > Import/Export from the main menu to select the desired option.