New database war shapes up "Database companies have been tackling the idea of the "federated," or virtual, database for years, although many attempts have failed because of the poor performance of distributed queries, said Philip Russom, an analyst with Giga Information Group. System complexity and the lack of a universal data language such as Extensible Markup Language (XML) also sidetracked earlier efforts... IBM's Xperanto, which builds on XML, a standard for data exchange, is based on the concept of federated data management. Instead of creating a single, larger database --a model, in part, espoused by rival Oracle--a federated scheme creates a virtual database linked to all the relevant data. In this model, data sources are queried from their native locations and database management servers consolidate the results and make them available to users."
Their method not only allows processing of XQuery on this data but also to convert XQuery into SQL if required. Querying XML Views of Relational Data. In the RDF word this idea is similar to Intellidimension's data services. Much like our full text models or querying RSS feeds.