Re: Managing Co-reference (Was: A Semantic Elephant?)

Kendall Grant Clark wrote:
> Excerpts from Kingsley Idehen's message of Wed May 14 14:59:29 -0400 2008:
>   
>> Owlgres is a PostgreSQL application. Why the DBMS specificity?
>>     
>
> Because it makes for a better name, obviously... ;>
>
> Seriously, it's not Postgres specific. We prefer Postgresql, but Owlgres ca
> run on any JDBC-compliant database. I suspect that, as it matures and we find a
> customer base for it, it will run on a variety of databases.
>   
Okay, the JDBC bit is good, and we can easily test Owlgres against 
Virtuoso JDBC.  But of course, we end up with the obvious question: Why 
are we using JDBC to talk to a DBMS engine equipped with a Quad Store? 
We've been through this re. recent work relating to new Model Providers 
for Sesame, Jena, and Redland (all of which offer SQL DBMS and Graph 
Model persistence  APIs).
>   
>> What does PosgreSQL offer that you may have assumed is/was missing from 
>> Virtuoso when developing this application?
>>     
>
> I don't know why you're assuming that I assumed anything, but the primary
> reasons we chose Postgresql were maturity, scalability, extensibility, vibrant
> after-market, BSD license, and PostGIS.
>   

Bad choice of words on my part re: is/was :-)

Since I haven't had time to look under the hood, I want you to assist me 
in understanding what PostgreSQL offered that lead to what I assumed was 
a PostgreSQL specific application.
>   
>> I've also added, Orri Erling (Program Manager Virtuoso), Ivan Mikhailov 
>> (Lead Developer of Virtuoso's Quad Store functionality realm), and Alan 
>> Rutternberg to this thread (Alan is interested in Owlgres and Virtuoso 
>> integration).
>>     
>
> If you'd like to have a conversation with Alan or others about Owlgres working
> w/ Virtuoso, we can do that offline or at SemTech next week, but I don't think
> it's very relevant here.
>   
Sure, we can take that offline, but note the context of my comments 
(above plus the bit below):

<<
> > *MikeUschold *noted that the computational issue of owl:sameAs proliferation
> > is a major problem, even if noone is going to load all the semantic web data
> > into a single store.  For today's triple stores that do limited inference,
> > owl:sameAs "has a significant run time" according both to common sense as
> > well as the developers of OpenLink's Virtuoso triple
> > store<http://docs.openlinksw.com/virtuoso/rdfsparqlrule.html#rdfsparqlruleintro>
> > .
> > They say it can easily double query
> > times<http://www.openlinksw.com/weblog/oerling/?id=1347>.
>   

You don't have to  do it at query time. Owlgres  does owl:sameAs processing at
load time and so the *query time*  cost is negligible. The usual caveats about
tradeoffs and use cases apply, of course.


 >>

 I am trying to determine if  we've ended up with  two things that are 
artificially disconnected :-)
> Cheers,
> Kendall
>
>   


-- 


Regards,

Kingsley Idehen	      Weblog: http://www.openlinksw.com/blog/~kidehen
President & CEO 
OpenLink Software     Web: http://www.openlinksw.com