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Re: RDF/XML/Internet Collisons, Process (was Moving on)

From: Dan Brickley <danbri@w3.org>
Date: Wed, 31 May 2000 17:45:28 -0400 (EDT)
To: xml-uri@w3.org
Message-ID: <Pine.LNX.4.20.0005311712340.23807-100000@tux.w3.org>


On Wed, 31 May 2000, Simon St.Laurent wrote:

> Okay, so the RDF WG decided to use XML...
> 
> [Also, the RDF spec doesn't make a strong commitment to XML.  From the
> Introduction:
> RDF>It is also important to understand that this 
> RDF>XML syntax is only one possible syntax for 
> RDF>RDF and that alternate ways to represent 
> RDF>the same RDF data model may emerge. 
> ]

Just wanted to respond to this aside for now; hopefully reply to the rest
later. The RDF model & syntax specification says this for good reason: by
making a clear distinction between the underlying RDF data model and the
initial RDF-in-XML syntax we make room for new ways of interpreting
various kinds of XML as RDF. Far from being a half-hearted commitment to
XML, I read this as anticipating a number of developments that couldn't be
specified in the RDF spec. For example, consider the mapping of Xlink
typed links into RDF, the use of XSLT or annotated schemas to extract RDF
models from 'mainstream' XML, or RDF interpretations of other compatible
graph-serialisation syntaxes (eg. SOAP). RDF also had a charter to provide
a metadata model that provides a common system across the wide variety of
pre-XML syntaxes, files formats etc in use on the Web (eg. PNG, MP3 etc),
not to mention the various other places data can live (eg. LDAP, RDBMS
etc). So separating the abstract model from our default XML syntax was
something of a necessity. 

RDF implementors tend to take XML's ubiquity for granted -- the attitude
seems to be "well, obviously everyone is going to use XML for everything
ever, that's wonderful, but what happens after that then...?". 
For example, I can learn the same fragment of information from any of the
RDF-mappable data sources I listed above, sometimes in XML,
sometimes not. The syntaxes may vary but the RDF representation can remain
constant. This turns out to be a rather useful feature.

IMHO, RDF's contribution to the XML picture seems to be as a
(partial) strategy for dealing with the enormous success of XML, by
providing a common data interpretation strategy de-coupled from any
particular XML syntax. When the RDF M&S spec takes care to
distinguish RDF's data model from one particular syntax, it is 
not through lack of enthusiasm for XML, but because this layering is 
a practical way of coping with the heterogeneity of the Web (pre- and
post- XML).

Dan


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Received on Wednesday, 31 May 2000 17:45:30 UTC

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