Re: [office-metadata] "Logical/abstract" vs. "physical" representation

["Bruce D'Arcus" <bdarcus@gmail.com>]

Michael,

I think we need to separate the question of document URI (the  
rdf:about value for the document per se) from formal XML base URI. I  
am saying we need the former, and that it needs to be unique and stable.

On Mar 5, 2007, at 11:33 AM, Michael Brauer - Sun Germany - ham02 -  
Hamburg wrote:

>> The point is, for the metadata system, they are *always* required  
>> if we want things to work reliably.
>
> I'm not sure about this. If I simply safe a document on my hard  
> drive, why do I need a different base IRI in this case then the one  
> the document gets because it is located somewhere on my hard drive?  
> All statements I make in this document using relative IRIs are in  
> the first place statements about certain ODF objects in exactly  
> that document.

A URI is an identifier; nothing more. It allows us to refer to  
resources; in this case documents and document fragments. If those  
URI are not persistant and globally unique, they are not very useful.

Example 1:

I have a field in my document with the xml:id value of "123."

The document file path is "file:///foo.odf".

A triple for that field thus might be:

<file:///foo.odf#123> dc:description "blah" .

The RDF/XML thus looks like:

<rdf:Description rdf:about="file:///foo.odf#123">
   <dc:description>blah</dc:description>
</rdf:Description>

If you move the file, the statements are invalid.

Example 2:

I want to represent the relations between different documents. I want  
to say file x.odf is a draft of file y.odf.

Triples, if there is no stable full URI:

<file:///y.odf> dcterms:isVersionOf <file:///x.odf> .

Again, what happens if the document moves? What happens if it moves  
to a desktop where a user has the exact same file name and path, but  
it is actually a different file?

Example 3:

Rob wants to enable his use case of external annotation of files.  
Same problem as above.

> And if I make a document accessible on a web server, why is another  
> base IRI required than the HTTP URI the document gets anyway. If  
> this is sufficient for the HTML case, why isn't it sufficient for  
> the ODF case?
>
> We have also to consider that a base IRI is applied to all realtive  
> IRIs. That is, it may actually break non-metadata IRI. So, this  
> feature has to be used with care.

As I said, we need a document URI. I'm saying it would be very bad  
practice to simply leave this an optional designation and for  
everyone to rely on file paths.

Whether those are used as formal xml:base values or not seems to me a  
separate matter.

Bruce