RE: Identity of URIRefs / Resources

Hi James,

I looked at < <http://taguri.org> http://taguri.org> and found your example: tag:hawke.org,2001-06-05:Taiko

May I ask for an example RDF/XML code snippet showing how you would use such tags?

>From a data modelling point of view it's not a very good method, because if the relationship between you and Taiko would no longer exist (e.g. you sell him) then Taiko would need another tag. That is not very helpful in case you want to gather the lifecycle information about Taiko. I can see why you came up with this solution, because it is a matter of descriptive identification, i.e. an identification by means of one or more properties. Filling out a form for entering the USA does the same: name, first name, date of birth, place of birth, nationality, gender, etc, until one can be reasonably certain that there is only one person that fits the pattern.

But that is besides the point, because my question to you is: what is wrong with a fragment identifier described, amongst others, in the RDF Primer? So something like  <http://www.hawke.org/index.html#Taiko-2005-06-05> http://www.hawke.org/index.html#Taiko-2005-06-05? What are the advantages of using your tagging method over that of using fragment identifiers? Or am I missing something?

Regards, Hans

=========================================================================

-----Original Message-----
From: semantic-web-request@w3.org [ <mailto:semantic-web-request@w3.org> mailto:semantic-web-request@w3.org] On Behalf Of James Cerra
Sent: zondag 5 juni 2005 4:52
To: semantic-web@w3.org; reto@gmuer.ch
Subject: Re: Identity of URIRefs / Resources


Reto,

Very nice and interesting CMS.  I have a similar idea; although, it isn't a server side app.  What does WYMIWYG stand for?  What You Make Is What You Get?

> If I understand  <http://www.w3.org/TR/rdf-concepts/#dfn-URI-reference> http://www.w3.org/TR/rdf-concepts/#dfn-URI-reference
> correctly, the following graph contains two statements :
> <snip>

Yes.  Even if they were the same URIs, though, there would _still be two statements_!  They would just be duplicates, but that is allowed in RDF's data model.

> Does it make sense that "Two RDF URI references are equal if and only
> if they compare as equal, character by character, as Unicode
> strings.",

Yes. That is correct.

> wouldn't it cause less problems to say "Two RDF URI references are
> equal if and only if the resolve to the same URI".

The problem is that two RDF URI references don't have to "resolve" to anything!
 They could point to a resource that is not network retrievable, for example.
For this reason, I think the tag URI scheme is a good idea for most URIs.  See < <http://taguri.org> http://taguri.org> for more info on that scheme.

> I'm asking because I'm implementing and RDF based CMS [1] where GET
> and MGET requests are answered according of the properties the
> requested resource has in the model and I have no way to find out
> whether the user requested  <http://gmuer.ch/%C3%BC> http://gmuer.ch/%C3%BC or  <http://example.org/??> http://example.org/��.

Take a look at the SPARQL protocol, which provides a standard way of using HTTP to get RDF information.  See < <http://www.w3.org/TR/rdf-sparql-protocol/> http://www.w3.org/TR/rdf-sparql-protocol/> for more information.



--
Jimmy Cerra
 <https://nemo.dev.java.net> https://nemo.dev.java.net


               
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