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Comments below:
On Wednesday, January 21, 1998 10:47 PM, Surendra Reddy
[SMTP:SKREDDY@us.oracle.com] wrote:
> Yaron,
>
> Adding properties: documentowner, annotations and documentretention
>
> Document Author/Owner and annotations are most important properties as
one
> defines
> who created the document and one carries review annotations --
>
> I agree with your decision of choosing properties only for proper
> functioning of the protocol.
> At the same time, we should also look at the basic document authoring
> requirements. In a large
> scale corporate document repositories at least one should know who
authored
> the document, all changes
> that has undergone since its first version and when to expire the
document
> from the repository.
> Also, these properties are fundamental for document management. From
this
> stand point of view
> I strongly argue that we should include document owner/author,
annotations
> and expiry/documentretention
> properties.
This is a well known rathole -- actually, it's more like quicksand, having
a surface appearance of solidity which conceals its traplike nature. Why?
Let me give a brief outline of the issues:
1) Unless you have *very* strict criteria on which properties are to be
allowed, it is impossible to develop a good reason why any one given
property shouldn't be included. This creates a log-rolling effect, where
everyone's favorite property is added because there is no good reason not
to add it. So, adding "owner/author" looks easy, but this quickly opens the
door for "publisher", "ISBN", "keywords", "LC number", etc.
2) It is really hard to define the semantics of each item. For example,
the Dublin Core group has developed a simple metadata schema for
bibliographic data for the Internet. Their schema includes items like:
Subject: The topic addressed by the work
Title: The name of the object
Author: The person(s) primarily responsible for the intellectual
content of the object
Publisher: The agent or agency responsible for making the object
available
OtherAgent: The person(s), such as editors and transcribers, who have
made other significant intellectual
contributions to the work
Date: The date of publication
ObjectType: The genre of the object, such as novel, poem, or
dictionary
Form: The data representation of the object, such as Postscript file
or Windows executable file
Identifier: String or number used to uniquely identify the object
Relation: Relationship to other objects
Source: Objects, either print or electronic, from which this object is
derived, if applicable
Language: Language of the intellectual content
Coverage: The spatial locations and temporal durations characteristic
of the object
(This list is from:
http://www.oclc.org:5046/oclc/research/conferences/metadata/dublin_core_
report.html, and is probably a little bit out-of-date.)
This list looks fairly obvious and trivial, yet it represents *thousands*
of person hours of discussion and work.
So, combine the log-rolling effect with the empirical evidence that these
metadata sets take a long time to precisely define, and you start to see
why this issue is a rathole. Of course, even if you do manage to create a
well-defined, stable set of properties, the next hurdle is defining
equivalence across multiple metadata sets -- I'll let the veterans of the
DMA effort describe how fun that was :-)
This issue has been disussed in the past on the mailing list -- Larry
Masinter's "Danger! Here Be Dragons" post is now indelibly etched in my
brain:
http://lists.w3.org/Archives/Public/w3c-dist-auth/1996OctDec/0069.html
Early development of the WebDAV property inclusion criteria can be seen in:
http://lists.w3.org/Archives/Public/w3c-dist-auth/1996OctDec/0078.html
OK, so I've established that this issue is a rathole. But you still have a
need for defining an author property. Here is how I would accomplish this
using the *existing* mechanisms and properties in the -06 WebDAV
specification:
Since WebDAV makes use of the XML namespace mechanism, it is possible to
combine together XML elements from different schema into the same document.
So, if you want an author property, use the existing Dublin Core metadata
set:
1) define a property (using PROPPATCH) for the author. In the Resource
Description Framework working group of the W3C (see
http://www.w3.org/TR/WD-rdf-syntax/ for an out-of-date, but publically
available draft) they have been adopting the convention of using the URL
"http://purl.org/DublinCore/RDFschema" for Dublin Core records. So, using
this URL as the base name of the property:
Property name = http://purl.org/DublinCore/RDFschema/Author
Property value:
<?namespace href="http://purl.org/DublinCore/RDFschema" as="DC"?>
<DC:Author>Herman Melville</DC:Author>
So, you can see that, using the very well defined semantics of the Dublin
Core, you can add an Author property to a WebDAV resource. This is far
better than having WebDAV define an identical property, since the library
science community has far greater credibility than this working group for
defining such a schema.
So, do you still feel we need an author property?
- Jim