W3C home > Mailing lists > Public > w3c-rdfcore-wg@w3.org > November 2001

Re: Issue rdfms-abouteach

From: Dave Beckett <dave.beckett@bristol.ac.uk>
Date: Fri, 16 Nov 2001 11:43:05 +0000
To: Patrick.Stickler@nokia.com
cc: w3c-rdfcore-wg@w3.org
Message-ID: <19972.1005910985@tatooine.ilrt.bris.ac.uk>
>>>Patrick.Stickler@nokia.com said:
> It is a useful syntactic convenience for folks who
> write their RDF/XML instances by hand.

I'm rather skeptical at how much that happens :)

For writing by hand, there are, ahem, non-XML syntaxes that are better.

> One can
> put a bunch of resources in a bag and then make
> an aboutEach statement. It also IMO can help make
> an RDF instance more readable with regards to
> common classifications of resources. E.g.
> <rdf:Bag rdf:ID="guys">
>    <rdf:li rdf:resource="#Bob"/>
>    <rdf:li rdf:resource="#John"/>
>    <rdf:li rdf:resource="#Joe"/>
>    <rdf:li rdf:resource="#Harry"/>
>    <rdf:li rdf:resource="#Frank"/>
>    <rdf:li rdf:resource="#Phil"/>
> </rdf:Bag>
> <rdf:Bag rdf:ID="gals">
>    <rdf:li rdf:resource="#Mary"/>
>    <rdf:li rdf:resource="#Elain"/>
>    <rdf:li rdf:resource="#Jane"/>
>    <rdf:li rdf:resource="#Betty"/>
>    <rdf:li rdf:resource="#Elizabeth"/>
>    <rdf:li rdf:resource="#Judeth"/>
> </rdf:Bag>
> <rdf:Description rdf:aboutEach="#guys">
>    <rdf:type rdf:resource="x:Male"/>
> </rdf:Description>
> <rdf:Description rdf:aboutEach="#gals">
>    <rdf:type rdf:resource="x:Female"/>
> </rdf:Description>

Can now be written as

 <rdf:Bag rdf:ID="guys">
    <rdf:li rdf:type="http://example.org/property/Male" rdf:resource="#Bob"/>
    <rdf:li rdf:type="http://example.org/property/Male" rdf:resource="#John"/>
    <rdf:li rdf:type="http://example.org/property/Male" rdf:resource="#Joe"/>
    <rdf:li rdf:type="http://example.org/property/Male" rdf:resource="#Harry"/>
    <rdf:li rdf:type="http://example.org/property/Male" rdf:resource="#Frank"/>
    <rdf:li rdf:type="http://example.org/property/Male" rdf:resource="#Phil"/>
 <rdf:Bag rdf:ID="gals">
    <rdf:li rdf:type="http://example.org/property/Female" rdf:resource="#Mary"/>
    <rdf:li rdf:type="http://example.org/property/Female" rdf:resource="#Elain"/>
    <rdf:li rdf:type="http://example.org/property/Female" rdf:resource="#Jane"/>
    <rdf:li rdf:type="http://example.org/property/Female" rdf:resource="#Betty"/>
    <rdf:li rdf:type="http://example.org/property/Female" rdf:resource="#Elizabeth"/>
    <rdf:li rdf:type="http://example.org/property/Female" rdf:resource="#Judeth"/>

> This is also very useful for asserting "local"
> classifications of resources for third-party
> knowledge where you cannot touch the original
> schemas.

It is a syntax-in-this-document thing; aboutEach over concepts in
other documents is I think, not allowed, since we decided in June
that the aboutEach distributed over top level nodes in the same
RDF/XML document.

  Ora Lassila has stated in a response that it was the intention of
  the working group that rdf:aboutEach attributes should be permitted
  only on top level description elements.
  Resolution: On 29th June 2001, the WG decided that rdf:aboutEach
  attributes are not allowed on an rdf:Description (or typed node)
  element which is the object of a statement.

  -- http://www.w3.org/2000/03/rdf-tracking/#rdfms-aboutEach-on-object

> I know of one standards group which is in the
> process of finalizing the decision to migrate
> to RDF and is planning on using aboutEach a good
> deal, though I'm not at liberty (yet) to say who 
> that is.
> *Please* leave it alone.

I would rather convince them to use something better rather than
intend to use this mechanism which is poorly implemented - mostly due
to its bad interactions with bagID, and its many corner cases.

> > -----Original Message-----


Received on Friday, 16 November 2001 06:43:08 UTC

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