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Re: I guess it’s a stupid questions…

From: Ivan Herman <ivan@w3.org>
Date: Sat, 13 Nov 2004 09:41:37 +0100
Message-ID: <4195C8C1.8060504@w3.org>
To: Petko Petkov <ppetkov@linuxmail.org>
Cc: www-rdf-interest@w3.org
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

Received on Saturday, 13 November 2004 08:41:44 UTC

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