The XML broker's declarative query language, itself noted as XML document, allows the definition of logical views on the data stored in the warehouse. A query consists of the selection of element types from an integrated DTD and constraints on their content and structural context. The query processor searches the warehouse for document fragments satisfying the constraints and assembles them in an XML result document. In our example scenario queries can be composed interactively using forms. Further research The ability to integrate heterogeneous sources into individual views makes the XML Broker a valuable tool for personal information management.
Further research aims to further reduce the overall expense required to open up new sources.
Combining machine learning methodology and a graphical user interface will enable untrained users to interactively specify the necessary grammars. Our second focus is to actively take part in the normative process for XML query languages.