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how to address RDF fragment

From: Hidetaka Ohto <ohto@w3.org>
Date: Wed, 19 Apr 2000 11:48:20 -0400
Message-ID: <005c01bfaa16$b09f5e20$aa001d12@w3.org>
To: <www-rdf-comments@w3.org>
Cc: <reagle@w3.org>, "Ralph R. Swick" <swick@w3.org>

Dear www-rdf-comments subscribers:

My name is Taka.
I am working on CC/PP WG which plans to use RDF 
for describing device capabilities.
Let me ask questions about how to address RDF fragment.

I would like to know how a RDF resource which is created
in a document should be annotated by another RDF description
which is in another document.

Q1: For example, is it possible to do that?
(As far as I know, there is no DTD(or XML Schema?) for RDF.
Therefore it seems to me that we could not resolve a URI
fragment ID using the knowledge of attribute types in DTD(ID), 
and need to use RDF specific resolution rules. 
However I do not know what it is.)

http://aaa/a.rdf 
-------------
<rdf:RDF xmlns:rdf="http://http://www.w3.org/1999/02/22-rdf-syntax-ns#"
  xmlns="http://xxx/xxx">
  <rdf:Description ID="a">
    <p1>v1</p1>
  </rdf:Description>
</rdf:RDF>

http://bbb/b.rdf
-------------
<rdf:RDF xmlns:rdf="http://http://www.w3.org/1999/02/22-rdf-syntax-ns#"
  xmlns="http://xxx/xxx">
<rdf:Description about="http://aaa/a.rdf#a">
  <p2>v2</p2>
</rdf:Description>
</rdf:RDF>

Q2: Can "bagID" and "ID" within one document have the same value(URI)?
(As far as I know, there is no restrictions in the RDF M&S spec but I guess
the answer is No.)

For example, 
<rdf:RDF xmlns:rdf="http://http://www.w3.org/1999/02/22-rdf-syntax-ns#"
  xmlns="http://xxx/xxx">
  <rdf:Description ID="a">
    <p1>v1</p1>
  </rdf:Description>
  <rdf:Description bagID="a">
    <p2>v2</p2>
  </rdf:Description>
</rdf:RDF>

Q3: When a RDF description is embedded in an XML application document using
name space, how should the RDF resource described by the RDF description be
annotated by another RDF description which is in another document?

For example,
(assuming the type of attribute "ccpp:ID" is ID in DTD.)

http://aaa/a.xml
---------------
<ccpp:Profile ccpp:ID="a" xmlns:ccpp="http://ccpp/ccpp" >
  <rdf:RDF xmlns:rdf="http://http://www.w3.org/1999/02/22-rdf-syntax-ns#"
    xmlns=http://xxx/xxx>
    <rdf:Description ID="a">
      <p1>v1</p1>
    </rdf:Description>
  </rdf:RDF>
</ccpp:Profile>

http://bbb/b.rdf
-------------
<rdf:RDF xmlns:rdf="http://http://www.w3.org/1999/02/22-rdf-syntax-ns#"
  xmlns="http://xxx/xxx">
<rdf:Description about=http://aaa/a.xml#a>  
      <!-- ? what is it addressing? I guess the answer is "ccpp:Profile" tag -->
      <!-- when I want to address the RDF resource "a" in a.xml, how to do that? -->
      <!-- I guess the answer is the RDF description in a.xml needs to have ccpp:ID? -->
  <p2>v2</p2>
</rdf:Description>
</rdf:RDF>

Q4: It seems to me that it would be nice if I had "xml:id".
I vaguely remember there was a discussion whether we should
have "xml:id" or not in somewhere...
Could you let me know what is wrong with "xml:id"?

Best Regards,
-- Taka
-----------------------------------------
 Hidetaka "Taka" Ohto
   Panasonic Technologies Inc
   Visiting Engineer at the W3C
      ohto@w3.org
      Fax +1-617-258 5999, Phone +1-617-258-0982
      MIT/LCS, 545 Tech. Sq. Cambridge MA 02139 USA
Received on Wednesday, 19 April 2000 11:45:38 GMT

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