Re: RDF vs. relational databases => move to semantic-web@w3.org

Upps, the W3C Postmaster says that www-rdf-interest@w3.org is outdated. So 
let' move the discussion to semantic-web@w3.org.

----- Original Message ----- 
From: "Chris Bizer" <bizer@zedat.fu-berlin.de>
To: "Sören Auer" <auer@informatik.uni-leipzig.de>; 
<semantic_web@googlegroups.com>
Cc: "revi s." <reviswami78@yahoo.com>; <www-rdf-interest@w3.org>
Sent: Tuesday, August 29, 2006 6:43 PM
Subject: Re: RDF vs. relational databases


>
> My to cents.
>
> I completely agree with Sören, that one strength of the RDF data model is 
> its flexibility.
>
> Two things that appear at least equality important to me and that are not 
> provided by the relational model are globally unique identifiers and 
> links.
>
> By using globally unique identifiers, everybody can add information about 
> a resource. By using links, you can refer from your resource to somebody 
> else's resource. Meaning that you can set a link from one database 
> (repository) to another, which clearly isn't possible with classical 
> relational database technology.
>
> Tim's tabulator browser [1] shows nicely how these links can be followed 
> by using URI dereferencing and the good old rdf:seeAlso property. I also 
> like Bastian's work on federated SPARQL queries [2], which shows how 
> globally unique identifiers enable queries over multiple data sources. So 
> the Semantic Web community is getting closer to having the access 
> paradigms of the classical web - browse and search - also work for the 
> Semantic Web.
>
> Thus, I think where the RDF model really starts playing it strengths is 
> data integration and data linkage. We are currently exploring data linkage 
> in the context of D2R Server [3] , a tool for publishing the content of 
> classical relational databases on the Web. D2R Server allows you to query 
> relational databases with SPARQL. Currently, we are extending the server 
> with URI dereferencing features, meaning that you can retrieve RDF 
> representations of the objects in your relational database. This will 
> allow you to set links between different relational databases, allow you 
> to refer from your webpage or blog to an object within a relational 
> database or use a tool like Tabulator to transparently browse from the 
> content of one relational database to the content of another.
>
> So my guess: If RDF is good for something, it is good for data integration 
> and data linkage.
>
> Cheers,
>
> Chris
>
> [1] http://www.w3.org/2005/ajar/About.html
> [2] http://darq.sourceforge.net/
> [3] http://www.wiwiss.fu-berlin.de/suhl/bizer/d2r-server/
>
>
> ----- Original Message ----- 
> From: "Sören Auer" <auer@informatik.uni-leipzig.de>
> To: <semantic_web@googlegroups.com>
> Cc: "revi s." <reviswami78@yahoo.com>; <www-rdf-interest@w3.org>
> Sent: Tuesday, August 29, 2006 4:39 PM
> Subject: Re: RDF vs. relational databases
>
>
>
> From my point of view (next to the distribution aspect) flexibility is
> a crucial difference between the RDF based Semantic Web representation
> techniques and databases:
>
> With databases schema changes are very time consuming operations - the
> whole repository and keys have to be reorganized. Triple stores on the
> contrary don't distinguish between data changes and ontology schema
> changes - both are finally just additions or deletions of triples.
> However, triple stores will probably never be able to compete with
> optimized database schemas with respect to query speed. So if you need
> high speed querying and you don't expect many schema changes use a
> RDBMS, if you want to be very flexible with your schema/ontology use a
> triple store. The RDF paradigm is also a bit more holistic in the sense
> that everything from data, schema to metadata is encoded in triples,
> while databases usually have different encoding techniques for each of
> these.
>
> Regards,
>
> Sören
>
>

Received on Tuesday, 29 August 2006 17:02:37 UTC