- From: Sebastian Hammer <quinn@indexdata.dk>
- Date: Sun, 11 Mar 2001 08:55:56 +0100
- To: Robert Waldstein <wald@library.ho.lucent.com>, www-zig@w3.org
At 10:58 09-03-01 -0500, Robert Waldstein wrote: > > The other place where I predict we will soon need to identify XML schemas > > is in the query, where we would like to address specific elements by tag > > path (preferably by using the existing XPath syntax) rather than by USE > > attributes. In a community that defines itself by XML-based data models, > > the tag-paths, after all, are probably the closest thing to abstract > access > > (ignorant question warning) > >Do you need a schema to use XPATH? I had the impression that you could use >XPATH style access to XML data independent of knowing anything about the >DTD/schema/or similar structural concepts. > If this is true you could put XPath strings in as attribute strings - might >want to indicate it is an "XPath string" - in which case might want an OID >saying "XPath", but would that then be sufficient? (ignorant response warning) To be honest, I don't know. If the client only supports one schema (or similar concept), or if they all share a certain level of structure, then yes, the client shouldn't have to say anything. But this seems to me to go against the grain of what Z39.50 is arguably good at - which is to separate local physical representation from shared abstractions. To put it differently, what if the server internally stores documents in a specific schema, but it has crosswalks to any number of other schemas to use for searching or retrieval. It seems to me to be desirable to be able to treat an XPath expression as an abstract thing - one that can be mapped into diffferent sorts of access point spaces. Again, to me it seems that for this to work well, the client should indicate clearly what schema *it* thinks it is addressing, to allow the server to make an intelligent judgment. But you're raising a real issue here... Ideally, I need my query to state BOTH that I am providing an XPATH expression and that I think it fits in with a certain schema. There's no standard way to identify a schema in the XPath expression itself, is there? --Sebastian -- Sebastian Hammer <quinn@indexdata.dk> Index Data ApS Ph.: +45 3341 0100 <http://www.indexdata.dk> Fax: +45 3341 0101
Received on Sunday, 11 March 2001 02:56:06 UTC