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RE: use of attribute to qualify property value

From: Chris Kaler (Exchange) <ckaler@Exchange.Microsoft.com>
Date: Thu, 20 May 1999 09:57:40 -0700
Message-ID: <FD7A762E588AD211A7BC00805FFEA54B01C297E5@HYDRANT>
To: "'jamsden@us.ibm.com'" <jamsden@us.ibm.com>, ietf-dav-versioning@w3.org, w3c-dist-auth@w3.org
The reason we had this was because there are different "types" of histories
that are available and different ways to "view" the history.  We modeled
this (in this draft) as a property, and rather than having "n*m" properties,
we used a qualifier.

I, personally, don't think that modeling history as a resource is viable
since there are several different ways that I want to view the history.
History information should be an XML "report".  I also don't share Yaron's
distaste for attributes.  I guess I'm a little suprised by the statement "It
seems weird to me that the value one gets back is affected by the
attribute".  What you get back is a function of the XML tag you request.
Attributes are qualifiers on the tag, right?  Seems logical to me :-) :-)


-----Original Message-----
From: jamsden@us.ibm.com [mailto:jamsden@us.ibm.com]
Sent: Thursday, May 20, 1999 5:03 AM
To: ietf-dav-versioning@w3.org; w3c-dist-auth@w3.org
Subject: Re: use of attribute to qualify property value

The history of a versioned resource doesn't seem like a resource to me, it
more like information, meta-data, about another resource of set of related
resources. This is a generated report, not a resource. Making it a resource
would likely result in redundant data in many server implementations, and
interfer with the user's namespace.

I don't share Yaron's view on the use of XML properties. They have some
advantages and disadvantages over content model, and DAV should not
any particular policy. It should be up to the client and data modeler to
See xml-dev for lots of discussion on using attributes vs. content.

"Geoffrey M. Clemm" <gclemm@tantalum.atria.com> on 05/19/99 05:03:35 AM

To:   ietf-dav-versioning@w3.org, w3c-dist-auth@w3.org
cc:    (bcc: Jim Amsden/Raleigh/IBM)

Subject:  Re: use of attribute to qualify property value

I believe the problem that led to the use of property attributes was
the attempt to model the "history" of a versioned resource as a
property.  If instead we model it as a resource (i.e. a "history resource"
that contains a collection of revisions), then we can just use
headers (like the Depth header) to modify the PROPFIND call that
is applied to this collection.


   From: Yaron Goland <yarong@microsoft.com>
   Cc: w3c-dist-auth@w3.org
   Date: Mon, 17 May 1999 17:46:57 -0700
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   As explained in detail in
   attributes are a bad idea.

   The use of attributes invariably indicates an ill considered data

   In this case they are used to avoid dealing with the issues of properties
   properties. Let us not avoid these hard problems but grabble them head


   > -----Original Message-----
   > From: Jim Davis [mailto:jdavis@coursenet.com]
   > Sent: Mon, May 17, 1999 4:35 PM
   > To: ietf-dav-versioning@w3.org
   > Cc: w3c-dist-auth@w3.org
   > Subject: use of attribute to qualify property value
   > In at least two places, the DeltaV draft protocol (Kaler et
   > al, Jan 20,
   > 1999) uses an attribute value to qualify the value of the
   > property returned
   > in a PROPFIND.  (The two places I've noticed are 5.2
   > defaulthistory, which
   > uses the limit attribute and 5.4 directlineage, which uses the scope
   > attribute).
   > This is a little funny, for two reasons
   > 1. As far as I know, WebDAV has never settled whether XML
   > attributes are
   > part of a property value (with the exception of the xml:lang
   > attribute). A
   > client can certainly store a property whose value includes
   > attributes, but
   > it's not clear that the server MUST preserve the attributes.
   > (Please don't
   > argue with me about whether it should or should not, all I am
   > saying is
   > that, to the best of my knowledge, it's an unsettled controversy)
   > 2. It seems weird to me that the value one gets back is
   > affected by the
   > attribute.  It's not like I expect proxies to be caching the values of
   > PROPFIND, but I would like some guidance as a client writer
   > about when two
   > properties can meaningfully be compared.  Clearly, in this
   > case, they can't
   > if the attributes differ.  Would you propose that, in
   > general, a property
   > can only be compared if all attributes are exactly the same?
   > This isn't
   > unreasonable, but I would like this settled for WebDAV in
   > general, and not
   > by accidental precedent in DeltaV
   > best regards
   > Jim
   > ps I'm new to DeltaV, apologies if this has already come up
Received on Thursday, 20 May 1999 12:57:44 UTC

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