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Grammer support for querying property values that are XML structu res?

From: Stephan, Eric G <Eric.Stephan@pnl.gov>
Date: Thu, 15 Jun 2000 10:41:14 -0700
To: www-webdav-dasl@w3.org
Message-id: <9E9DBE33F0E9D211AC5F0008C7A4E1F4653BE1@PNLMSE10.pnl.gov>
My basic question is:  Will (does) the DASL protocol define a grammer be used to
query and return parts of a property value if that value is an XML structure?  

It seems to me that the DASL basic grammer is geared to query simple
unstructured property values (e.g. strings, numbers, possibly dates), but not
structured values such as an XML structure.  To support this (if my impressions
are correctabout the basic grammer) a separate grammer needs to be created to
allow me to do this.

Please let me know if I have overlooked something and my impressions are
incorrect.  If I am correct I'd like to hear from you on how to deal with XML
structured values in queries, grammers that are being explored, leaving the
problem to the client etc.

Below I have included an example of the problems we hope DASL can solve for us.

Thanks,

Eric Stephan
Sr. Research Scientist
Battelle - Pacific Northwest National Laboratory
P.O. Box 999, MS K1-96
Richland, WA  99352
Phone:    509-375-6977
Fax:        509-375-6631
Email:     eric.stephan@pnl.gov


Here is our problem using DAV today:

Given the non-hierarchical view of properties on a given document/collection we
are taking advantage of storing structured values in XML as shown below:

<DAV:prop>
  <bogus:foo-model>
    <name>calculation</name>
    <version>1.0</version>
    <foo-author>
      <name>Math Ematics</name>
      <email>mailto:mathematics@bogus.com</email>
    </foo-author>
  </bogus:foo-model>
</DAV:prop>


Some problems that a XML value query grammer could help solve:
	1) How do you query a property value stored in an XML structure that
contains an XML element whose value is equal, not, equal, like, >, < etc..
	Two examples come to mind:
		-Find collections/documents with the bogus:foo-model value whose
value contains <name> = "calculation" AND <version> not equal to 0.0.
		-Determine which bogus:foo-model <version> is greater than 0.0

	2)  How do you return only part of the property value in the result of
the query?  
		Example:  Return the foo-model name and foo-model foo-model
foo-author name

What I want the format my my query result property value to look like when it is
returned from DAV:
  	 <bogus:foo-model>
     		<name/>
     		<foo-author>
       			<name/>
		</foo-author>
   	</bogus:foo-model>
Received on Thursday, 15 June 2000 13:42:05 GMT

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