Yeah, but what's the performance like when
* the database is on the other side of the country?
* the data is too big to fit in RAM?
We've been burned by simple-minded implementations of RDF that did not
account for such.
> -----Original Message-----
> From: Eric Prud'hommeaux [mailto:eric@stripped]
> Sent: Thursday, April 19, 2007 4:03 PM
> To: Renato Golin
> Cc: Jay Pipes; MySQL Internals
> Subject: Re: semantic storage engine
>
> * Renato Golin <rengolin@stripped> [2007-04-19 22:19+0100]
> > On 19/04/07, Eric Prud'hommeaux <eric@stripped> wrote:
> > >I'm fuzzy on the criteria for a semantic database, but SPASQL is a
> > >project aimed at providing RDF access to conventional
> relational data.
> > >There's a project page [SP], a talk I gave at XTech [SX] and a cvs
> > >repository [SC].
> >
> > Thanks, very enlighting pages!
> >
> > Also read some others after googling for sparql & mysql.
> But I didn't
> > noticed that sparql wouldn't allow us to query on a semantic data
> > structure as well. Sesame (openrdf.org) uses on called
> SeRQL which is
> > a bit different but not far from SQL as well.
>
> If I recall, SeRQL has a few points of expressivity that don't exist
> in SPARQL: existentials, set difference, transitive closures (and
> builtin predicates to avoid transitive closures).
>
> When you say "query on a semantic data structure", do you mean to
> query the relational structure, much like "SHOW COLUMNS FROM"?
> virtuoso may do that out of the box. You could add that to
> SPASQL/MySQL. I'd look to d2rq for a good graph convention for
> expressing structre schema
>
> > >At some point, I'd like to add a triple store for stuff
> that doesn't
> > >fit in the relational schema. This is prototyped in
> FeDeRate (Algae2
> > >test case [TC]). Also want to port the query federation
> stuff to the
> > >MySQL implementation (use case [FD]).
> >
> > I saw some perl modules on your page but didn't downloaded
> them, will
> > take a closer look.
>
> The perl stuff is a query re-writer, and probably not too interesting
> to a MySQL hacker up to their elbows in C++. I'd be happy to happy to
> geek about it, though.
>
> >
> > >Steve Harris, of garlik.com, has implemented a triple
> store, but not
> > >within MySQL. He might be interested in this work.
> >
> > There is also Sesame but I didn't go that deep yet to study
> the tool.
> > One colleague of mine said it is the standard today for storing RDFs
> > but it won't have all the other "added benefits" MySQL have.
>
> The standardisation work at W3C is focused around SPARQL.
> http://www.w3.org/TR/rdf-sparql-query/
>
> I don't know of any RDF query language standardization work in other
> standards bodies. (It's such a beautiful irony that "standardisation"
> can be spelled two ways?)
>
> > Anyway, I'm still probing as I don't need it straight away but using
> > MySQL will always be on top of my list, if available. Also, if there
> > is a trend on that already I'd be very glad to be part of it.
> >
> > cheers,
> > --renato
> >
> > Reclaim your digital rights, eliminate DRM, learn more at
> > http://www.defectivebydesign.org/what_is_drm
> >
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> -eric
>
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