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Re: RDB structure to RDF mapping

From: Pat Hayes <phayes@ihmc.us>
Date: Sun, 24 Apr 2016 23:00:09 -0500
Cc: Alessandro Seganti <a.seganti@cognitum.eu>, Paul Tyson <phtyson@sbcglobal.net>, Semantic Web <semantic-web@w3.org>
Message-Id: <27C2B729-5CE6-4A2F-9A75-52A38F7EC9EC@ihmc.us>
To: Juan Sequeda <juanfederico@gmail.com>
Hi Juan

I confess that did know, but had forgotten, about your excellent work. I really ought to stop commenting on such emails :-)

Pat

On Apr 24, 2016, at 7:11 PM, Juan Sequeda <juanfederico@gmail.com> wrote:

> Pat,
> 
> 
> On Sat, Apr 23, 2016 at 11:23 PM, Pat Hayes <phayes@ihmc.us> wrote:
> 
> On Apr 22, 2016, at 2:47 AM, Alessandro Seganti <a.seganti@cognitum.eu> wrote:
> 
>> Thank you all for your answers!
>> So if I understood correctly the answer is: there is no standard to deal with modeling of the structure of RDBs. I started doing this by using instances as it seems to me the simplest way. I am trying to make an ontology as much as possible compatible with R2RML but there is not much to use apart from logicalTable and a couple of relations.
>> 
>> This said, do you think that is there a reason why none has thought of a standard for this kind of mapping?
> 
> It is an issue that many people have felt should be tackled, and it seems obvious how to start, but the details become very hard and have defeated all attempts to standardize such a mapping. For example, nothing in RDF can behave in the way that null behaves in RDBs, and RDF is agressively open-world in its underlying semantic model. 
> 
> Are you aware 
> 
> On Directly Mapping Relational Databases to RDF and OWL. WWW2012
> http://web.ing.puc.cl/~marenas/publications/www12b.pdf
> 
> We address the issues that you mention. 
> 
>  
> 
> I wish you well in your attempt to do this: if you feel you are succeeding, please publicize your efforts as they may be widely useful. 
> 
> Pat Hayes
> 
>> Maybe because in most use cases people want to map only specific queries to RDF graphs instead of mapping the whole database structure to an RDF graph?
>> 
>> Regards,
>> Alessandro
>> 
>> Alessandro Seganti Ph.D.
>> 
>> Cognitum Sp. z o.o., Data Engineer
>> 
>> mail: a.seganti@cognitum.eu, tel: +48 22 250 2541, fax: +48 22 250 28 98
>> 
>> web: http://www.cognitum.eu/, fb: facebook.com/cognitum.eu
>> 
>> 
>> On Tue, Apr 19, 2016 at 8:13 PM, Paul Tyson <phtyson@sbcglobal.net> wrote:
>> On Mon, 2016-04-18 at 17:25 +0200, Alessandro Seganti wrote:
>> > Hi everyone,
>> > I want to formalize in RDF the table structure of a relational
>> > database. What I would like to do is to formalize the links that
>> > exists between all the tables inside a given relational database. This
>> > would result in a graph where the nodes are the tables and the links
>> > are the columns that can be used to join these tables.
>> >
>> >
>> > My question is: is there some standard/ontology to describe this?
>> >
>> >
>> > To my understanding the R2RML ontology is to describe mappings between
>> > RDB and RDF (no RDB structure is mentioned). I also found a document
>> > about direct mapping but no ontology is defined in this document.
>> >
>> 
>> When the RDB2RDF WG was working I suggested including an RDB ontology.
>> But it was considered out of scope so nothing of the sort was included
>> in their final deliverables.
>> 
>> http://lists.w3.org/Archives/Public/public-rdb2rdf-wg/2010Oct/0055.html
>> 
>> My work didn't (and doesn't) involve RDBMS deeply enough to pursue this,
>> so I don't know how valuable this would be for practical tasks.
>> 
>> Regards,
>> --Paul
>> >
>> >
>> >
>> > Thank you for your help.
>> > Alessandro Seganti Ph.D.
>> >
>> > Cognitum Sp. z o.o., Data Engineer
>> >
>> > mail: a.seganti@cognitum.eu, tel: +48 22 250 2541, fax: +48 22 250 28
>> > 98
>> >
>> > web: http://www.cognitum.eu/, fb: facebook.com/cognitum.eu
>> >
>> >
>> 
>> 
>> 
> 
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> 
> 
> 
> 
> 

------------------------------------------------------------
IHMC                                     (850)434 8903 home
40 South Alcaniz St.            (850)202 4416   office
Pensacola                            (850)202 4440   fax
FL 32502                              (850)291 0667   mobile (preferred)
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Received on Monday, 25 April 2016 04:01:24 UTC

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