Automated mapping of conceptual schemas to relational schemas

Many CASE tools for information systems engineering can input a conceptual data model of an application and map this to a logical data model for implementation. Typically this involves mapping an ER (Entity-Relationship) conceptual schema to a relational database schema. Since the graphic notation of ER, or the mapping algorithm itself, fails to capture many constraints and derivation rules, these additional features must be coded up manually. Object-Role Modelling (ORM) provides a simpler and richer notation, enabling most of these additional features to be catered for in the mapping. The most well known version of ORM is NIAM, and a number of CASE tools now support this method. Recently, an extended ORM language called FORML has been developed which is even more expressive, and a complete mapping algorithm has been developed and automated. This paper provides an overview of the mapping algorithm and the use of role-graphs for automation