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RDF/XML (was Re: Requirements for a possible "RDF 2.0")

From: Jeremy Carroll <jeremy@topquadrant.com>
Date: Fri, 15 Jan 2010 08:34:52 -0800
Message-ID: <4B50992C.2060904@topquadrant.com>
To: Danny Ayers <danny.ayers@gmail.com>
CC: Steve Harris <steve.harris@garlik.com>, Semantic Web <semantic-web@w3.org>

I think there is substantial misunderstanding about what is important in 
an RDF serialization.

A key advantage of RDF/XML and NTriples was that the RDF Core WG put a 
lot of effort into making sure that everyone in the community process 
them in the same way. That matters.

I find that many Jena users care that their RDF/XML is vaguely readable.
A triple oriented form (which is supported by RDF/XML), such as that 
output by the simple writer in Jena, is disliked.
My completely cosmetic work in 2002 or 2003 on RDF/XML output in a more 
readable form, and the various N3/turtle writers is widely liked.

Given this, a triple oriented format like TriX will not succeed.
It is more important that people can glance at an RDF/XML file and get 
some feel for it, than for an XML tool to be able to process it.
To process an RDF file, the correct way is to read it with an RDF tool.

So here is a prioritized list of features:

1) (a) well defined, (b) implemented with interoperability
2) processable with RDF tools
3) generatable by non-RDF tools
4) can be eyeballed by SemWeb developers
5) processable by non RDF tools

RDF/XML and turtle have 1,2,3 and 4

TriX has 1a, 2, 3, and to some extent 5
NTriples has 1,2,3 and 5.

4 is more important than 5

Also note that, in practice, processing RDF with non RDF tools is a 
complete pain, because you have to follow the paths through the data, 
which in DB terms is a self join. So if you have a TriX like format, the 
XSLT to follow a simple s p1 p2 p3 o path is really quite a pain to code 
and probably fairly inefficient with the typical XSLT implementation.

The cost of a new standard syntax is probably upwards of $1M and is not 
worth it.

Jeremy




Danny Ayers wrote:
> 2010/1/15 Jeremy Carroll <jeremy@topquadrant.com>:
>   
>> Steve Harris wrote:
>>     
>>>> * an RDF/XML profile (as above) designed for maximum compatibility
>>>> with XPath/XSLT/XQuery
>>>>         
>>> That would be nice. I often thing that RDF/XML is not a terribly good way
>>> to encode RDF in XML.
>>>       
>> TriX was meant to address that need. I do not believe its take up has been
>> significant.
>> For several years now my view has been that RDF/XML is an obviously flawed
>> system, with no compelling alternative.
>>     
>
> As an aside, do you think that if the W3C had (or would) put it's
> stamp on TriX, even just as a note with examples, it would (have)
> gained more uptake?
>
> There was the clunky 1998/99ish RDF/XML stuff which had eyeballs from
> xml-dev on it, but until relatively recently it seemed like the XML
> world and the RDF world were completely different planets. Now with
> the likes of Jeni & Bob DuCharme jumping on board the RDF raft it
> seems there is real crossover. (Not to mention the OpenLink one store,
> many views approach).
>
> Cheers,
> anny.
>
>   
Received on Friday, 15 January 2010 16:35:45 UTC

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