W3C home > Mailing lists > Public > www-webdav-dasl@w3.org > July to September 1999

RE: JW10: QSD usage

From: Niket Patwardhan <niket@verity.com>
Date: Mon, 09 Aug 1999 17:03:51 -0700
Message-Id: <199908100002.raa25745@verity.com>
To: Jim Davis <jrd3@alum.mit.edu>, Jim Whitehead <ejw@ics.uci.edu>, "Babich, Alan" <ABabich@filenet.com>, "'DASL'" <www-webdav-dasl@w3.org>
I think the key is what you mean by "succeed". The SQL model is to flag
problems (such as column names that don't exist) as an error, causing the
whole query to fail. The usual text retrieval philosophy is to avoid
returning errors, by treating that portion of the query as either true,
false or don't care. Given that type of philosophy, things would always
succeed, but would return more or less documents depending on the server.

As a data point, the Dublin Core work has determined some items that should
definitely be in, so it might be useful to pick up those.

(As an introduction)
Niket Patwardhan
Director, Standards & Technology
Verity, Inc.

At 01:27 PM 8/9/99 -0700, Jim Davis wrote:
>At 02:46 PM 7/20/99 -0700, Jim Whitehead wrote:
>
>>I've been thinking about this aspect of QSD, and I have some concerns.
>>Perhaps I'm misunderstanding, but it appears we're creating a situation
>>where a client A can submit a DASL query to server X and have it succeed,
>>and submit the same query to server Y and have it not succeed because server
>>Y doesn't index the same properties as server X.  Is this correct?
>
>It's probably correct but to be precise it depends what you mean by
>"succeed" and "index". 
>
>But the underlying problem is not one DASL can address.  As I see it, the
>issue is that there are only a few standard property names in WebDAV.  Thus
>while one might query against the DAV:getcontenttype or DAV:gencontentsize
>and expect this to work on all servers, there is no way to search against
>more interesting fields such as author, title, publisher, cost, etc.
>(Well, the DAV:getdisplayname property might be the title).
>
>Eventually the Dublin Core work might produce a standard set of DAV
>properties to encode DC values, but not yet.
>
>Given this lack of standardization, QSD is the next best thing.  At least
>it provides a way to discover the set of searchable properties.  This
>allows a UI to put up a list of the available properties.
>
>So DASL, as written, does not allow a robot to do interesting queries (e.g.
>against author) on an arbitrary server (because the robot has no way to
>know what property if any holds the author name).  But it does allow a
>human to do it (assuming you can guess from the property name or associated
>meta-property info).
>
>Does this addess your concern?
> 
Received on Monday, 9 August 1999 20:03:04 GMT

This archive was generated by hypermail 2.2.0+W3C-0.50 : Sunday, 22 March 2009 03:38:04 GMT