W3C home > Mailing lists > Public > www-rdf-interest@w3.org > May 2001

RE: relational mapping?

From: Andrew Hill <ahill@openlinksw.com>
Date: Thu, 3 May 2001 12:24:49 -0400
To: "Jan Grant" <Jan.Grant@bristol.ac.uk>, "Seth Russell" <seth@robustai.net>
Cc: "Danny Ayers" <danny@panlanka.net>, "Www-Rdf-Logic" <www-rdf-logic@w3.org>, "RDF-Interest" <www-rdf-interest@w3.org>
Message-ID: <NDBBKFNCBCHANEGAKONKKEEBIFAA.ahill@openlinksw.com>
On a related note, Virtuoso http://www.openlinksw.com/virtuoso/ can produce
XML docs in realtime from local relational tables (within the Virtuoso
database) or remote relational data (including heterogenous joins across
multiple databases).  The DTD or XMLSchema can be automatically generated or
explicitly defined, and there is a built in XSLT processor as well, so you
can transform the XML to whatever format you like.

Let me know if you have any questions.

Hope this helps!

Best regards,
Andrew
--------------------------------------
Andrew Hill - OpenLink Software
Director Technology Evangelism
Universal Data Access Integration
http://www.openlinksw.com


> -----Original Message-----
> From: www-rdf-interest-request@w3.org
> [mailto:www-rdf-interest-request@w3.org]On Behalf Of Jan Grant
> Sent: Thursday, May 03, 2001 12:08 PM
> To: Seth Russell
> Cc: Danny Ayers; Www-Rdf-Logic; RDF-Interest
> Subject: Re: relational mapping?
>
>
> On Thu, 3 May 2001, Seth Russell wrote:
>
> > From: "Jan Grant" <Jan.Grant@bristol.ac.uk>
> >
> > > On Thu, 3 May 2001, Danny Ayers wrote:
> > >
> > > > Has anyone come across a mapping of the relational model to RDF? I'm
> > sure
> > > > there's a pretty direct one possible at a low level (tuple
> to tuple I
> > > > suppose), but it'll save me some thought and a lot of time
> if someone's
> > > > already looked into this. Alternatively, if there's an RDFS
> around that
> > > > contains RDBMS terms (schema, table, column etc) I'd very
> much like to
> > hear
> > > > about it. I'm wanting to operate at this latter level, but
> it would be
> > nice
> > > > to be on firm foundations.
> > >
> > > I've done quite a bit of thinking about it; got some paper notes which
> > > I'm in the (slow) process of typing up. You're right, there's a simple
> > > mechanical mapping of rows in a table to RDF; what you lose by this is
> > > the natural linking of properties.
> > >
> > > For a sufficiently normalised relational schema*, you can generally
> > > produce a mapping
> > > (primary key) -> resource
> > > (other values) -> properties
> > > (foreign key) -> link to resource representing primary key for
> > > foreign table
> > >
> >
> > No doubt you are aware of the list of these recorded at [1], to
> which list I
> > have added the structure diagrammed at [2].
> >
> > [1] http://www-db.stanford.edu/~melnik/rdf/db.html
> > [2] http://robustai.net/mentography/SemStructure.gif
>
> Neat; but these seem to be "storing RDF in RDBMS" as opposed to
> "producing RDF from a (legacy?) RDBMS"
>
> --
> jan grant, ILRT, University of Bristol. http://www.ilrt.bris.ac.uk/
> Tel +44(0)117 9287163 Fax +44 (0)117 9287112 RFC822 jan.grant@bris.ac.uk
> "Sufficiently large"="infinite" for sufficiently large values of
> "sufficiently"
>
>
Received on Thursday, 3 May 2001 12:27:25 GMT

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