Agora: Living with XML and Relational
Ioana Manolescu, Daniela Florescu, Donald Kossmann, Florian Xhumari, Dan Olteanu · 2000
Introduction There has been a significant body of research in the last fifteen years dedicated to integration of data from various repositories, exhibiting heterogeneous formats, and sometimes access restrictions; for a survey of such systems see, for example, [12]. The main technical issues to be addressed in a mediation system are: how to semantically unify heterogeneous data formats and schemas, and how to use query processing capabilities of participant data sites and that of the mediator in order to answer a particular query. Systems like the Information Manifold, and Garlic from IBM have chosen the relational and respectively the object-oriented model as the integration model. Given the popularity of XML as a data description format, more and more DBMS manufacturers have added to their systems the capability to export relational or object-oriented data to an XML format; other data formats (flat data files, regular HTML, PowerPoint presentations, annotated text) are also