From XML DTDs to Entity-Relationship Schemas

The need for managing large repositories of data coming from XML documents is increasing; in fact, XML is emerging as the standard format for documents exchanged over the internet. At University of Bergamo, recently we developed the ERX Data Management System, to study issues concerning the management of data coming from XML documents; its data model, called ERX (Entity Relationship for XML), being an extension of the classical ER model, allows to deal with concepts coming from XML documents at the conceptual level, and allows to reason about integration of data coming from different XML document classes. This paper focuses on the problem of automatically deriving Entity-Relationship Schemas (ERX Schemas) from DTDs (Document Type Definition). In fact, the derivation of such schemas from DTDs might be a hard work to do by hand, since real DTDs are very complex and large.