Re: RDB structure to RDF mapping

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 <email@cognitum.eu>, tel: +48 22 250 2541,
> fax: +48 22 250 28 98
>
> web: *http://www.cognitum.eu/ <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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