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Re: Abstract Schemas in XML-Queries

From: Peter Fankhauser <fankp@darmstadt.gmd.de>
Date: Mon, 2 Oct 2000 06:14:01 +0200
To: <www-xml-query-comments@w3.org>
Cc: <levan@oclc.org>, <w3c-xml-query-wg@w3.org>
Message-ID: <KNEAKBHGPLOADKCAOIFNAEDOCBAA.fankp@darmstadt.gmd.de>
Dear Ralph LeVan,

Thank you for your comment in
http://lists.w3.org/Archives/Public/www-xml-query-comments/2000Aug/0023.html

Your use case can be regarded as an instance of Usage Scenario 2.2
in the requirements document at http://www.w3.org/TR/xmlquery-req:
"The XML representation of data sources may be either
physical or virtual; that is, data may be physically encoded in XML,
or an XML representation of the data may be produced." In the scenario
you sketch, the database of records may not be in XML, but the server
may provide a "virtual" XML view on the database. The view will be
represented in the form of XML Schema or a DTD, and the database
can be queried via this view. However, the mapping between the XML view
and the underlying (non-XML) database is not in the realms of XML Query.

A more special case is to perform queries against an XML database
with a particular XML Schema (the "server Schema") through a view
according to another XML Schema (the "client Schema"). XML Query
can in principle form the basis for specifying the mapping between
the "server Schema" and the "client Schema". But XML Query 1.0 will
not define a view definition language. A view definition language may
be considered in future versions of XML Query.

Peter Fankhauser
Received on Monday, 2 October 2000 00:12:14 UTC

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