Re: RDF2RDB 0.5

Hello Paola,

if you do not want to lose information, the relational data model I use is 
quite straightforward and coming up with something different would be difficult
for me.

Of course, things look different if you take the purpose of the RDB user into
account and multiple possibilities open. If you look at the relationals dumps
of timbls FOAF file generated by the tool
(http://www.netestate.de/De/Loesungen/RDF2RDB), you will see that a plethora
of tables is created with the same information often repeated in several
tables. From the view of a RDB user, the semantic web can be quite "messy".

The user will have to pick the tables that are interesting for him and maybe
even bring them into another form. But at least he can do this exploration and
restructuring of the information with the tools he knows best and does not
have to learn much about technologies that may be completely new to him
beforehand.

Regards,

Michael Brunnbauer

On Sun, Aug 05, 2012 at 03:52:59PM +0100, Paola Di Maio wrote:
> could be very useful!
> 
> (anything that avoids the use of sparql must be useful)
> </joke>
> 
>  however, suspect that there is a modelling challenge
> and possibly some software already exists that does that
> 
> modelling challenge:
> 
> to create relational databases,  it is necessary to model data
> ie to define  what to put in columns , in raws, the granularity, and a
> bunch of other stuff, including normalisation (check codds relational
> principles)
> 
> this is conceptual work that only an intelligent and trained human can
> do (that I know of) and even so, its hardly 'right' or 'wrong' rather
> a function of purpose (variable, not standardizable)
> 
> RDF, from what I know, is typically unstructured data
> (unless it has been RDFIZED form data previously modelled and
> extracted from DBs, but I assume this is not the kind of RDF that you
> are targeting here)
> 
>  what you propose, as I understand it, could be useful if you can get
> the system to model/represent rdf unstructred into
> meaningful/structured relational data
> 
> If however you could come up with a web service that enables a user to
> create structured data models from unstructured ones, then I think
> that would be groundbreaking work and I d love to see something
> (unless its already available and I am not aware of it then please point)
> 
> cheers
> 
> PDM
> 
> 
> 
> 
> 
> On Sun, Aug 5, 2012 at 2:03 AM, Michael Brunnbauer <brunni@netestate.de> wrote:
> >
> > hi all
> >
> > to support the proliferation of RDF, I have begun work on a tool to convert
> > RDF data into relational databases. It is intended for people who want to use
> > data available only as RDF but do not have the patience to install a triple
> > store and learn SPARQL. I know there are tools that present a SQL view
> > over a triple store but installing such an environment also is quite
> > challenging.
> >
> > There has been work on real "converters" in the past, especially the paper from
> > Wajee Teswanich and Suphamit Chittayasothorn:
> >
> >  http://hcotuk.etu.edu.tr/semanticweb/A%20Transformation%20from%20RDF%20Documents%20and%20Schemas%20to%20Relational%20Databases.pdf
> >
> > My tool works much like the one described in this paper (has it ever been
> > implemented ?), with important differences:
> >
> > -It supports incremental runs (adding more RDF data to a database later)
> >
> > -It supports entailment (rdfs:subClassOf, rdfs:subPropertyOf, rdfs:domain,
> >  rdfs:range, owl:equivalentClass, owl:equivalentProperty,
> >  owl:FunctionalProperty)
> >
> > The software is written in Python and uses the RDFLib Python library. It works
> > with local and remote files. You can find more information and download it at
> >
> >  http://www.netestate.de/De/Loesungen/RDF2RDB
> >
> > There also example database dumps for
> >
> >  http://www.w3.org/People/Berners-Lee/card.rdf
> >
> > and
> >
> >  http://www.w3.org/People/Berners-Lee/card.rdf
> >  +
> >  http://xmlns.com/foaf/spec/index.rdf
> >
> > there.
> >
> > Don't rant about the invalid skolem URIs - you can set the skolem URI prefix
> > to something valid in the configuration :-)
> >
> > So far this has just been fun and I would like to have some feedback on the
> > usefulness before I spend more time on it.
> >
> > Regards,
> >
> > Michael Brunnbauer
> >
> > --
> > ++  Michael Brunnbauer
> > ++  netEstate GmbH
> > ++  Geisenhausener Straße 11a
> > ++  81379 München
> > ++  Tel +49 89 32 19 77 80
> > ++  Fax +49 89 32 19 77 89
> > ++  E-Mail brunni@netestate.de
> > ++  http://www.netestate.de/
> > ++
> > ++  Sitz: München, HRB Nr.142452 (Handelsregister B München)
> > ++  USt-IdNr. DE221033342
> > ++  Geschäftsführer: Michael Brunnbauer, Franz Brunnbauer
> > ++  Prokurist: Dipl. Kfm. (Univ.) Markus Hendel
> >

-- 
++  Michael Brunnbauer
++  netEstate GmbH
++  Geisenhausener Straße 11a
++  81379 München
++  Tel +49 89 32 19 77 80
++  Fax +49 89 32 19 77 89 
++  E-Mail brunni@netestate.de
++  http://www.netestate.de/
++
++  Sitz: München, HRB Nr.142452 (Handelsregister B München)
++  USt-IdNr. DE221033342
++  Geschäftsführer: Michael Brunnbauer, Franz Brunnbauer
++  Prokurist: Dipl. Kfm. (Univ.) Markus Hendel

Received on Monday, 6 August 2012 06:44:22 UTC