Re: SQL to RDF access ?

[Kingsley Idehen]

On 10/13/15 12:52 PM, Kingsley Idehen wrote:
> On 10/2/15 10:47 AM, Jerven Bolleman wrote:
>> Hi,
>>
>> In Oracle, I think you can create a view on a select on sem_match. e.g.
>>
>> CREATE VIEW proteinOrganism AS
>> SELECT p AS PROTEIN, o AS ORGANISM FROM TABLE(SEM_MATCH(
>> 'PREFIX c: SELECT ?p ?o WHERE {?p a
>> c:Protein . ?p c:organism ?o}',
>> SEM_MODELS('UNIPROT_2015_08'), null, null, null));
>>
>> Something similar is possible in Virtuoso, and surely DB2
>>
>> In PostgreSQL, you could use
>> https://github.com/cyga/www_fdw/wiki/Documentation
>> to map sparql results into views.
>>
>> However, all will requires certain maintenance workloads.
>>
>> For the experimental stuff you could look at MonetDB/RDF or
>> Virtuoso-CS (not yet public)
>> http://homepages.cwi.nl/~duc/papers/emergentschema_www15.pdf
>> 
>>
>> Regards,
>> Jerven
>>
>
> Virtuoso translates SPARQL to SQL at its core i.e., that's what
> Virtuoso is, fundamentally.
>
> Virtuoso also let's you leverage RDF Relations constructed from SPARQL
> in the FROM CLAUSE of a SQL Query (we call this SPASQL, and it's
> existed since day one).
>
> Here is a simple SPASQL Query where an RDF relation is used in the SQL
> FROM CLAUSE:
>
> SELECT "x"."o"
> FROM (SPARQL SELECT DISTINCT ?o  {?s rdf:type ?o} LIMIT 100) AS  "x"
>
> Links:
>
> [1] http://bit.ly/spasql-query-demo-entity-types -- Live instance of
> SQL and/or SPARQL Query Tool

Forgot to mention, when challenged for credentials, its "vdb" for
username and pwd.

-- 
Regards,

Kingsley Idehen   
Founder & CEO 
OpenLink Software 
Company Web: http://www.openlinksw.com
Personal Weblog 1: http://kidehen.blogspot.com
Personal Weblog 2: http://www.openlinksw.com/blog/~kidehen
Twitter Profile: https://twitter.com/kidehen
Google+ Profile: https://plus.google.com/+KingsleyIdehen/about
LinkedIn Profile: http://www.linkedin.com/in/kidehen
Personal WebID: http://kingsley.idehen.net/dataspace/person/kidehen#this



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Re: SQL to RDF access ?

[Kingsley Idehen]

On 10/2/15 10:47 AM, Jerven Bolleman wrote:
> Hi,
>
> In Oracle, I think you can create a view on a select on sem_match. e.g.
>
> CREATE VIEW proteinOrganism AS
> SELECT p AS PROTEIN, o AS ORGANISM FROM TABLE(SEM_MATCH(
> 'PREFIX c: SELECT ?p ?o WHERE {?p a
> c:Protein . ?p c:organism ?o}',
> SEM_MODELS('UNIPROT_2015_08'), null, null, null));
>
> Something similar is possible in Virtuoso, and surely DB2
>
> In PostgreSQL, you could use
> https://github.com/cyga/www_fdw/wiki/Documentation
> to map sparql results into views.
>
> However, all will requires certain maintenance workloads.
>
> For the experimental stuff you could look at MonetDB/RDF or
> Virtuoso-CS (not yet public)
> http://homepages.cwi.nl/~duc/papers/emergentschema_www15.pdf
> 
>
> Regards,
> Jerven
>

Virtuoso translates SPARQL to SQL at its core i.e., that's what Virtuoso
is, fundamentally.

Virtuoso also let's you leverage RDF Relations constructed from SPARQL
in the FROM CLAUSE of a SQL Query (we call this SPASQL, and it's existed
since day one).

Here is a simple SPASQL Query where an RDF relation is used in the SQL
FROM CLAUSE:

SELECT "x"."o"
FROM (SPARQL SELECT DISTINCT ?o  {?s rdf:type ?o} LIMIT 100) AS  "x"

Links:

[1] http://bit.ly/spasql-query-demo-entity-types -- Live instance of SQL
and/or SPARQL Query Tool

-- 
Regards,

Kingsley Idehen   
Founder & CEO 
OpenLink Software 
Company Web: http://www.openlinksw.com
Personal Weblog 1: http://kidehen.blogspot.com
Personal Weblog 2: http://www.openlinksw.com/blog/~kidehen
Twitter Profile: https://twitter.com/kidehen
Google+ Profile: https://plus.google.com/+KingsleyIdehen/about
LinkedIn Profile: http://www.linkedin.com/in/kidehen
Personal WebID: http://kingsley.idehen.net/dataspace/person/kidehen#this



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Description: S/MIME Cryptographic Signature

Re: SQL to RDF access ?

[Andrea Splendiani]

Hi,
I know d2rq, but that maps relational to RDF.
I am looking the other way around.
As far as I have seen, that’s not something d2rq is designed for.
Or am I wrong ?

best,
Andrea

> On Oct 2, 2015, at 2:34 PM, Richard Boyce  wrote:
> 
> Hi Andrea, I think that D2R Server is very helpful here: 
> http://d2rq.org/d2r-server 
> 
> All can be done with a mapping file that you configure. The server provides a 
> SPARQL web query  interface (SNORQL) but also can dump to an RDF file that 
> you load in a separate store. 
> 
> hope it helps,
> -R
> 
> On 10/02/2015 07:37 AM, Andrea Splendiani wrote:
>> Hi,
>> 
>> I am wondering if some of you knows of some tool that can translate (a 
>> subset) of SQL to SPARQL (perhaps requiring some constraints on the RDF 
>> representation).
>> In principle it should be simple: classes can appear as tables, URIs as IDs, 
>> datatype properties as columns and object properties as Fkeys.
>> Is there something implementing this translation available, that some of you 
>> know ? One current option (I think) is via Oracle, but I am wondering if 
>> there is something like-weight.
>> 
>> As of why I am interested in it... it's curious: I may have an RDF graph 
>> representing a unified set of sources (some of which native in RDF, some of 
>> which virtualized from SQL). 
>> Still people like to query the sql sources in sql, just because they know it 
>> better. But like this, they miss the whole integration (and a more flexible 
>> data model).
>> 
>> best,
>> Andrea 
> 
> 
> -- 
> Richard D Boyce, PhD
> Assistant Professor of Biomedical Informatics
> Faculty, Center for Pharmaceutical Policy and Prescribing 
> Faculty, Geriatric Pharmaceutical Outcomes and Gero-Informatics Research and 
> Training Program
> University of Pittsburgh
> rd...@pitt.edu 
> Office: 412-648-9219
> Twitter: @bhaapgh

Re: SQL to RDF access ?

[Andrea Splendiani]

Thanks, I'll have a look.

best,
Andrea

On Fri, Oct 2, 2015 at 4:58 PM, Achille Zappa <
achille.za...@insight-centre.org> wrote:

> Hi,
>
> at the moment the only real related project I am aware of on this topic is
> (was?):
>
> RETRO: A Framework for Semantics Preserving SQL-to-SPARQL Translation?
> take a look at the paper at http://ceur-ws.org/Vol-784/evodyn3.pdf
>
> But I am not sure if it is available/alive in some way..
>
> Regards
> Achille
>
>
>
> On 2 October 2015 at 15:47, Jerven Bolleman  wrote:
>
>> Hi,
>>
>> In Oracle, I think you can create a view on a select on sem_match. e.g.
>>
>> CREATE VIEW proteinOrganism AS
>> SELECT p AS PROTEIN, o AS ORGANISM FROM TABLE(SEM_MATCH(
>> 'PREFIX c: SELECT ?p ?o WHERE {?p a
>> c:Protein . ?p c:organism ?o}',
>> SEM_MODELS('UNIPROT_2015_08'), null, null, null));
>>
>> Something similar is possible in Virtuoso, and surely DB2
>>
>> In PostgreSQL, you could use
>> https://github.com/cyga/www_fdw/wiki/Documentation
>> to map sparql results into views.
>>
>> However, all will requires certain maintenance workloads.
>>
>> For the experimental stuff you could look at MonetDB/RDF or Virtuoso-CS
>> (not yet public)
>> http://homepages.cwi.nl/~duc/papers/emergentschema_www15.pdf
>>
>> Regards,
>> Jerven
>>
>>
>>
>> On Fri, Oct 2, 2015 at 3:04 PM, Mikel Egaña Aranguren <
>> mikel.egana.arangu...@gmail.com> wrote:
>>
>>> Hi;
>>>
>>> My understanding is that Andrea wants the opposite: rewrite SQL queries
>>> to SPARQL queries, not access to SQL DBs with SPARQL. Anyway if the latter
>>> is the case, apart from D2R, the new Stardog release includes virtual
>>> graphs to access tabular (SQL, CSV files, ... ) data:
>>> http://docs.stardog.com/#_virtual_graphs.
>>>
>>> Mikel
>>>
>>> 2015-10-02 14:34 GMT+02:00 Richard Boyce :
>>>
 Hi Andrea, I think that D2R Server is very helpful here:
 http://d2rq.org/d2r-server

 All can be done with a mapping file that you configure. The server
 provides a SPARQL web query  interface (SNORQL) but also can dump to an RDF
 file that you load in a separate store.

 hope it helps,
 -R


 On 10/02/2015 07:37 AM, Andrea Splendiani wrote:

 Hi,

 I am wondering if some of you knows of some tool that can translate (a
 subset) of SQL to SPARQL (perhaps requiring some constraints on the RDF
 representation).
 In principle it should be simple: classes can appear as tables, URIs as
 IDs, datatype properties as columns and object properties as Fkeys.
 Is there something implementing this translation available, that some
 of you know ? One current option (I think) is via Oracle, but I am
 wondering if there is something like-weight.

 As of why I am interested in it... it's curious: I may have an RDF
 graph representing a unified set of sources (some of which native in RDF,
 some of which virtualized from SQL).
 Still people like to query the sql sources in sql, just because they
 know it better. But like this, they miss the whole integration (and a more
 flexible data model).

 best,
 Andrea



 --
 Richard D Boyce, PhD
 Assistant Professor of Biomedical Informatics
 Faculty, Center for Pharmaceutical Policy and Prescribing
 Faculty, Geriatric Pharmaceutical Outcomes and Gero-Informatics Research 
 and Training Program
 University of pittsburghrd...@pitt.edu
 Office: 412-648-9219
 Twitter: @bhaapgh


>>>
>>>
>>> --
>>> Mikel Egaña Aranguren, Ph.D.
>>>
>>> http://mikeleganaaranguren.com
>>>
>>>
>>>
>>
>>
>> --
>> Jerven Bolleman
>> m...@jerven.eu
>>
>
>
>
> --
> Achille Zappa
> Post-Doctoral Researcher at INSIGHT @ NUI Galway
> - The Centre for Data Analytics
> Linked Data Strand
> Insight   W3C Advisory Committee Representative
> Galway, Ireland
>

Re: SQL to RDF access ?

[Andrea Splendiani]

Hi,
thanks, I'll have a look at the paper.
I know I can handle it via some DB, but I was looking into something more
like D2RQ or even non-declarative in this case, as a default mapping would
be pretty plain. Basically to have something portable across triple stores.

best,
Andrea

On Fri, Oct 2, 2015 at 4:47 PM, Jerven Bolleman  wrote:

> Hi,
>
> In Oracle, I think you can create a view on a select on sem_match. e.g.
>
> CREATE VIEW proteinOrganism AS
> SELECT p AS PROTEIN, o AS ORGANISM FROM TABLE(SEM_MATCH(
> 'PREFIX c: SELECT ?p ?o WHERE {?p a
> c:Protein . ?p c:organism ?o}',
> SEM_MODELS('UNIPROT_2015_08'), null, null, null));
>
> Something similar is possible in Virtuoso, and surely DB2
>
> In PostgreSQL, you could use
> https://github.com/cyga/www_fdw/wiki/Documentation
> to map sparql results into views.
>
> However, all will requires certain maintenance workloads.
>
> For the experimental stuff you could look at MonetDB/RDF or Virtuoso-CS
> (not yet public)
> http://homepages.cwi.nl/~duc/papers/emergentschema_www15.pdf
>
> Regards,
> Jerven
>
>
>
> On Fri, Oct 2, 2015 at 3:04 PM, Mikel Egaña Aranguren <
> mikel.egana.arangu...@gmail.com> wrote:
>
>> Hi;
>>
>> My understanding is that Andrea wants the opposite: rewrite SQL queries
>> to SPARQL queries, not access to SQL DBs with SPARQL. Anyway if the latter
>> is the case, apart from D2R, the new Stardog release includes virtual
>> graphs to access tabular (SQL, CSV files, ... ) data:
>> http://docs.stardog.com/#_virtual_graphs.
>>
>> Mikel
>>
>> 2015-10-02 14:34 GMT+02:00 Richard Boyce :
>>
>>> Hi Andrea, I think that D2R Server is very helpful here:
>>> http://d2rq.org/d2r-server
>>>
>>> All can be done with a mapping file that you configure. The server
>>> provides a SPARQL web query  interface (SNORQL) but also can dump to an RDF
>>> file that you load in a separate store.
>>>
>>> hope it helps,
>>> -R
>>>
>>>
>>> On 10/02/2015 07:37 AM, Andrea Splendiani wrote:
>>>
>>> Hi,
>>>
>>> I am wondering if some of you knows of some tool that can translate (a
>>> subset) of SQL to SPARQL (perhaps requiring some constraints on the RDF
>>> representation).
>>> In principle it should be simple: classes can appear as tables, URIs as
>>> IDs, datatype properties as columns and object properties as Fkeys.
>>> Is there something implementing this translation available, that some of
>>> you know ? One current option (I think) is via Oracle, but I am wondering
>>> if there is something like-weight.
>>>
>>> As of why I am interested in it... it's curious: I may have an RDF graph
>>> representing a unified set of sources (some of which native in RDF, some of
>>> which virtualized from SQL).
>>> Still people like to query the sql sources in sql, just because they
>>> know it better. But like this, they miss the whole integration (and a more
>>> flexible data model).
>>>
>>> best,
>>> Andrea
>>>
>>>
>>>
>>> --
>>> Richard D Boyce, PhD
>>> Assistant Professor of Biomedical Informatics
>>> Faculty, Center for Pharmaceutical Policy and Prescribing
>>> Faculty, Geriatric Pharmaceutical Outcomes and Gero-Informatics Research 
>>> and Training Program
>>> University of pittsburghrd...@pitt.edu
>>> Office: 412-648-9219
>>> Twitter: @bhaapgh
>>>
>>>
>>
>>
>> --
>> Mikel Egaña Aranguren, Ph.D.
>>
>> http://mikeleganaaranguren.com
>>
>>
>>
>
>
> --
> Jerven Bolleman
> m...@jerven.eu
>

Re: SQL to RDF access ?

[Achille Zappa]

Hi,

at the moment the only real related project I am aware of on this topic is
(was?):

RETRO: A Framework for Semantics Preserving SQL-to-SPARQL Translation?
take a look at the paper at http://ceur-ws.org/Vol-784/evodyn3.pdf

But I am not sure if it is available/alive in some way..

Regards
Achille



On 2 October 2015 at 15:47, Jerven Bolleman  wrote:

> Hi,
>
> In Oracle, I think you can create a view on a select on sem_match. e.g.
>
> CREATE VIEW proteinOrganism AS
> SELECT p AS PROTEIN, o AS ORGANISM FROM TABLE(SEM_MATCH(
> 'PREFIX c: SELECT ?p ?o WHERE {?p a
> c:Protein . ?p c:organism ?o}',
> SEM_MODELS('UNIPROT_2015_08'), null, null, null));
>
> Something similar is possible in Virtuoso, and surely DB2
>
> In PostgreSQL, you could use
> https://github.com/cyga/www_fdw/wiki/Documentation
> to map sparql results into views.
>
> However, all will requires certain maintenance workloads.
>
> For the experimental stuff you could look at MonetDB/RDF or Virtuoso-CS
> (not yet public)
> http://homepages.cwi.nl/~duc/papers/emergentschema_www15.pdf
>
> Regards,
> Jerven
>
>
>
> On Fri, Oct 2, 2015 at 3:04 PM, Mikel Egaña Aranguren <
> mikel.egana.arangu...@gmail.com> wrote:
>
>> Hi;
>>
>> My understanding is that Andrea wants the opposite: rewrite SQL queries
>> to SPARQL queries, not access to SQL DBs with SPARQL. Anyway if the latter
>> is the case, apart from D2R, the new Stardog release includes virtual
>> graphs to access tabular (SQL, CSV files, ... ) data:
>> http://docs.stardog.com/#_virtual_graphs.
>>
>> Mikel
>>
>> 2015-10-02 14:34 GMT+02:00 Richard Boyce :
>>
>>> Hi Andrea, I think that D2R Server is very helpful here:
>>> http://d2rq.org/d2r-server
>>>
>>> All can be done with a mapping file that you configure. The server
>>> provides a SPARQL web query  interface (SNORQL) but also can dump to an RDF
>>> file that you load in a separate store.
>>>
>>> hope it helps,
>>> -R
>>>
>>>
>>> On 10/02/2015 07:37 AM, Andrea Splendiani wrote:
>>>
>>> Hi,
>>>
>>> I am wondering if some of you knows of some tool that can translate (a
>>> subset) of SQL to SPARQL (perhaps requiring some constraints on the RDF
>>> representation).
>>> In principle it should be simple: classes can appear as tables, URIs as
>>> IDs, datatype properties as columns and object properties as Fkeys.
>>> Is there something implementing this translation available, that some of
>>> you know ? One current option (I think) is via Oracle, but I am wondering
>>> if there is something like-weight.
>>>
>>> As of why I am interested in it... it's curious: I may have an RDF graph
>>> representing a unified set of sources (some of which native in RDF, some of
>>> which virtualized from SQL).
>>> Still people like to query the sql sources in sql, just because they
>>> know it better. But like this, they miss the whole integration (and a more
>>> flexible data model).
>>>
>>> best,
>>> Andrea
>>>
>>>
>>>
>>> --
>>> Richard D Boyce, PhD
>>> Assistant Professor of Biomedical Informatics
>>> Faculty, Center for Pharmaceutical Policy and Prescribing
>>> Faculty, Geriatric Pharmaceutical Outcomes and Gero-Informatics Research 
>>> and Training Program
>>> University of pittsburghrd...@pitt.edu
>>> Office: 412-648-9219
>>> Twitter: @bhaapgh
>>>
>>>
>>
>>
>> --
>> Mikel Egaña Aranguren, Ph.D.
>>
>> http://mikeleganaaranguren.com
>>
>>
>>
>
>
> --
> Jerven Bolleman
> m...@jerven.eu
>



-- 
Achille Zappa
Post-Doctoral Researcher at INSIGHT @ NUI Galway
- The Centre for Data Analytics
Linked Data Strand
Insight   W3C Advisory Committee Representative
Galway, Ireland

Re: SQL to RDF access ?

[Jerven Bolleman]

Hi,

In Oracle, I think you can create a view on a select on sem_match. e.g.

CREATE VIEW proteinOrganism AS
SELECT p AS PROTEIN, o AS ORGANISM FROM TABLE(SEM_MATCH(
'PREFIX c: SELECT ?p ?o WHERE {?p a
c:Protein . ?p c:organism ?o}',
SEM_MODELS('UNIPROT_2015_08'), null, null, null));

Something similar is possible in Virtuoso, and surely DB2

In PostgreSQL, you could use
https://github.com/cyga/www_fdw/wiki/Documentation
to map sparql results into views.

However, all will requires certain maintenance workloads.

For the experimental stuff you could look at MonetDB/RDF or Virtuoso-CS
(not yet public)
http://homepages.cwi.nl/~duc/papers/emergentschema_www15.pdf

Regards,
Jerven



On Fri, Oct 2, 2015 at 3:04 PM, Mikel Egaña Aranguren <
mikel.egana.arangu...@gmail.com> wrote:

> Hi;
>
> My understanding is that Andrea wants the opposite: rewrite SQL queries to
> SPARQL queries, not access to SQL DBs with SPARQL. Anyway if the latter is
> the case, apart from D2R, the new Stardog release includes virtual graphs
> to access tabular (SQL, CSV files, ... ) data:
> http://docs.stardog.com/#_virtual_graphs.
>
> Mikel
>
> 2015-10-02 14:34 GMT+02:00 Richard Boyce :
>
>> Hi Andrea, I think that D2R Server is very helpful here:
>> http://d2rq.org/d2r-server
>>
>> All can be done with a mapping file that you configure. The server
>> provides a SPARQL web query  interface (SNORQL) but also can dump to an RDF
>> file that you load in a separate store.
>>
>> hope it helps,
>> -R
>>
>>
>> On 10/02/2015 07:37 AM, Andrea Splendiani wrote:
>>
>> Hi,
>>
>> I am wondering if some of you knows of some tool that can translate (a
>> subset) of SQL to SPARQL (perhaps requiring some constraints on the RDF
>> representation).
>> In principle it should be simple: classes can appear as tables, URIs as
>> IDs, datatype properties as columns and object properties as Fkeys.
>> Is there something implementing this translation available, that some of
>> you know ? One current option (I think) is via Oracle, but I am wondering
>> if there is something like-weight.
>>
>> As of why I am interested in it... it's curious: I may have an RDF graph
>> representing a unified set of sources (some of which native in RDF, some of
>> which virtualized from SQL).
>> Still people like to query the sql sources in sql, just because they know
>> it better. But like this, they miss the whole integration (and a more
>> flexible data model).
>>
>> best,
>> Andrea
>>
>>
>>
>> --
>> Richard D Boyce, PhD
>> Assistant Professor of Biomedical Informatics
>> Faculty, Center for Pharmaceutical Policy and Prescribing
>> Faculty, Geriatric Pharmaceutical Outcomes and Gero-Informatics Research and 
>> Training Program
>> University of pittsburghrd...@pitt.edu
>> Office: 412-648-9219
>> Twitter: @bhaapgh
>>
>>
>
>
> --
> Mikel Egaña Aranguren, Ph.D.
>
> http://mikeleganaaranguren.com
>
>
>


-- 
Jerven Bolleman
m...@jerven.eu

Re: SQL to RDF access ?

[Mikel Egaña Aranguren]

Hi;

My understanding is that Andrea wants the opposite: rewrite SQL queries to
SPARQL queries, not access to SQL DBs with SPARQL. Anyway if the latter is
the case, apart from D2R, the new Stardog release includes virtual graphs
to access tabular (SQL, CSV files, ... ) data:
http://docs.stardog.com/#_virtual_graphs.

Mikel

2015-10-02 14:34 GMT+02:00 Richard Boyce :

> Hi Andrea, I think that D2R Server is very helpful here:
> http://d2rq.org/d2r-server
>
> All can be done with a mapping file that you configure. The server
> provides a SPARQL web query  interface (SNORQL) but also can dump to an RDF
> file that you load in a separate store.
>
> hope it helps,
> -R
>
>
> On 10/02/2015 07:37 AM, Andrea Splendiani wrote:
>
> Hi,
>
> I am wondering if some of you knows of some tool that can translate (a
> subset) of SQL to SPARQL (perhaps requiring some constraints on the RDF
> representation).
> In principle it should be simple: classes can appear as tables, URIs as
> IDs, datatype properties as columns and object properties as Fkeys.
> Is there something implementing this translation available, that some of
> you know ? One current option (I think) is via Oracle, but I am wondering
> if there is something like-weight.
>
> As of why I am interested in it... it's curious: I may have an RDF graph
> representing a unified set of sources (some of which native in RDF, some of
> which virtualized from SQL).
> Still people like to query the sql sources in sql, just because they know
> it better. But like this, they miss the whole integration (and a more
> flexible data model).
>
> best,
> Andrea
>
>
>
> --
> Richard D Boyce, PhD
> Assistant Professor of Biomedical Informatics
> Faculty, Center for Pharmaceutical Policy and Prescribing
> Faculty, Geriatric Pharmaceutical Outcomes and Gero-Informatics Research and 
> Training Program
> University of pittsburghrd...@pitt.edu
> Office: 412-648-9219
> Twitter: @bhaapgh
>
>


-- 
Mikel Egaña Aranguren, Ph.D.

http://mikeleganaaranguren.com

Re: SQL to RDF access ?

[Richard Boyce]

Hi Andrea, I think that D2R Server is very helpful here: 
http://d2rq.org/d2r-server


All can be done with a mapping file that you configure. The server 
provides a SPARQL web query  interface (SNORQL) but also can dump to an 
RDF file that you load in a separate store.


hope it helps,
-R

On 10/02/2015 07:37 AM, Andrea Splendiani wrote:

Hi,

I am wondering if some of you knows of some tool that can translate (a 
subset) of SQL to SPARQL (perhaps requiring some constraints on the 
RDF representation).
In principle it should be simple: classes can appear as tables, URIs 
as IDs, datatype properties as columns and object properties as Fkeys.
Is there something implementing this translation available, that some 
of you know ? One current option (I think) is via Oracle, but I am 
wondering if there is something like-weight.


As of why I am interested in it... it's curious: I may have an RDF 
graph representing a unified set of sources (some of which native in 
RDF, some of which virtualized from SQL).
Still people like to query the sql sources in sql, just because they 
know it better. But like this, they miss the whole integration (and a 
more flexible data model).


best,
Andrea



--
Richard D Boyce, PhD
Assistant Professor of Biomedical Informatics
Faculty, Center for Pharmaceutical Policy and Prescribing
Faculty, Geriatric Pharmaceutical Outcomes and Gero-Informatics Research and 
Training Program
University of Pittsburgh
rd...@pitt.edu
Office: 412-648-9219
Twitter: @bhaapgh