A Validatable Legacy Database Migration Using ORM

This paper describes a method used in a real-life case of a legacy database migration. The difficulty of the case lies in the fact that the legacy application to be replaced has to remain fully available during the migration process while at the same time data from the old system is to be integrated within the new system. The target database schema was fixed beforehand, hence complicating and limiting our choices in constructing a possible target schema. The conceptual approach of the Object-Role Modeling (ORM) method helped us to better understand the semantics of the source and target system and enabled us to abstract from implementation choices in both the source and the target schemas. We discuss how our method could help in executing other legacy data migration projects. © 2012 Springer-Verlag.