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Re: RE: I guess it's a stupid questions.

From: Janne Saarela <janne.saarela@profium.com>
Date: Sat, 13 Nov 2004 11:11:11 +0200
Message-ID: <KMS--1199374644-20248@profium.com>
To: "McNaughton" <mcnaughton@wanadoo.fr>
Cc: info@oilit.com, www-rdf-interest@w3.org

Trying to give you a serious answer:

People with relational algebra background would
see the triples 'universal relation' as any database
schema/single table can be decomposed into (Subject, Predicate, Object) binary relationship.

People with natural language processing background
would see the triples as 'Janne eats an apple' type
of general sentence construct (S, P, O).

As these triples rarely appear alone, there is currently
interest in evolving this 3-tuple formalism into N-tuples where
N > 3. The 4th item could be either a graph name or a
provenance indicator where the triple originates from.

We'll have to be careful not to break RDF specifications
from early this year (2004) by introducing new tuple
items when new uses cases arrive...


> A related (stupid?) query...
> Why has the triple come to have such importance?
> What is magic about the number 3?
> Is it because the Simpsons have 3 fingers on each hand?
> Neil McNaughton
> Editor - Oil IT Journal (www.oilit.com)
> -----Original Message-----
> From: www-rdf-interest-request@w3.org
> [mailto:www-rdf-interest-request@w3.org] On Behalf Of Ivan Herman
> Sent: 13 November 2004 09:42
> To: Petko Petkov
> Cc: www-rdf-interest@w3.org
> Subject: Re: I guess it's a stupid questions.
> Petko,
> first of all, there are no stupid questions here. These things are not
> simple.
> My *personal* take is: do not try to say one is better than the other.
> Nobody says RDF is 
> better than XML (or XML is better than RDF for that matter); they are
> different. It is 
> like comparing apples and oranges. Actually, the basic triple store model of
> RDF is 
> completely independent from XML (in this sense, I think you made a mistake
> saying 'RDFS 
> goes on the top of XML'; that is not true). It just so happens that once you
> have the 
> basic model of RDF (and RDFS) you need a way to express it in a machine
> readable form, and 
> RDF/XML is *one of those* syntaxes. Note that there are lots of people out
> there who do 
> not like RDF/XML at all and use other kinds of 'serializations', like
> turtle, n3... And 
> that is absolutely fine, it is just syntactic sugar.
> What you need is to understand the requirements of your application. If you
> want to 
> express data that has a strong hierarchy then, please, use XML and forget
> about RDF. To 
> take a well known example: the <li> element in XHTML will be rendered
> differently by a 
> browser depending on its level of nesting, ie, its position in the whole
> hierarchy of the 
> XHTML tree. So using XML to express XHTML is the right choice and nobody in
> a proper state 
> of mind should try to reformulate XHTML into RDF...
> On the other hand, if your data is a 'loose' set of elementary
> relationships, that 
> different application might interpret differently for different purposes,
> and that you 
> might want to combine easily with other, similar loose sets of relationships
> at some point 
> in time, then use RDF. That is where the RDF data model is strong and good:
> it does not 
> impose any type of hierarchy and makes merging of different sources of RDF
> very easy.
> I hope this helps.
> Ivan
> Petko Petkov wrote:
> > I guess it's a stupid question, but I still do not understand why RDF is
> better than just XML. I understand that XML is just an approach of describe
> other markup languages and I believe that RDFS goes on the top of XML.
> That's great, but, we are making our lives harder again and again. Simple
> XML tags are much powerful than RDF statements and the triplets can be
> represented in much simpler way using namespaces. 
> > 
> > I have read somewhere that XML and XML Schemas are not good because XSD
> implies specific rules on the document structure. I find this explanation
> rather stupid than complete. XSD have the capabilities to include into a
> particular element different elements that may come from different namespace
> for example. 
> > 
> > I examined Firefox structure to see real RDF examples. Although, Firefox
> is just the best browser in the world, RDFS can be replaced by XML.
> > 
> > Can somebody explain to me?
> > 
> > Thanks
> > 
> -- 
> Ivan Herman
> W3C Communications Team, Head of Offices
> C/o W3C Benelux Office at CWI, Kruislaan 413
> 1098SJ Amsterdam, The Netherlands
> tel: +31-20-5924163; mobile: +31-641044153;
> URL: http://www.w3.org/People/all?pictures=yes#ivan

Janne Saarela <janne.saarela at profium.com>
Profium, Lars Sonckin kaari 12, 02600 Espoo, Finland
Internet: http://www.profium.com
Received on Saturday, 13 November 2004 09:11:19 UTC

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