There is also Sparqlify[1], which we use for exposing OpenStreetMap as LinkedData in the
"LinkedGeoData" project[2] (and dumpig the RDF for downloads)[3].
Unfortunately, R2RML support not yet totally stable; we wrote our mappings[4] in what we
refer to as "Sparqlification Mapping Language" (SML) [5] (release should be
ready soon).
In a nutshell, the relation between R2RML to SML is a bit akin to (the SPARQL
elements of) SPIN to SPARQL, for a pretty comprehensive comparision of examples
(the R2RML test suite) see [6].
Cheers,
Claus
[1] https://github.com/AKSW/Sparqlify (Instructions for installing Sparqlify
from the debian package are included there)
[2] LinkedGeoData: http://linkedgeodata.org
[3] http://downloads.linkedgeodata.org/releases
[4]
https://github.com/GeoKnow/LinkedGeoData/blob/master/linkedgeodata-core/src/main/resources/org/aksw/linkedgeodata/sml/LinkedGeoData-Triplify-IndividualViews.sml
[5] http://sml.aksw.org
[6] http://sml.aksw.org/comparison/sml-r2rml-loc-table.html
On 31.03.2014 01:29, Martynas Jusevičius wrote:
There are also commercial options, e.g. this:
http://www.revelytix.com/content/spyder
On Sun, Mar 30, 2014 at 10:15 PM, Kamalraj Jairam
<kjai...@semanticsoftware.com.au> wrote:
Hello Paul,
These are the informtion i have
1) R2RML mapping for existing DB
2) I have some fedreated queries which hit the triple store containg the data
which has been loaded from the DB
The Loading data from DB (100 tables, millions of rows) to TS takes a long
time. I need a framework to convert Sparql to SQL which will hit the table and
return RDF result set.
D2RQ is in version .81 and hasn't changed much. Not sure whether D2RQ is the
right approach.
Thanks
Kamalraj
--
Kjairam
Sent with Airmail
On 31 March 2014 at 6:59:20 am, Paul Tyson
(phty...@sbcglobal.net<mailto:phty...@sbcglobal.net>) wrote:
On Sun, 2014-03-30 at 09:37 +0000, Kamalraj Jairam wrote:
Hello All,
Whats the best way to convert sparql to SQL using R2RML mappings
and convert resultset from DB to RDF?
What are the givens? Do you have existing SPARQL text written against
some RDF produced by some existing R2RML mappings? Or do you have some
SPARQL and some SQL and you want to fill in the R2RML and produce some
RDF?
In any case, it is an interesting scenario that will arise more often as
companies expand their use of RDF while relying mostly on SQL.
There is a higher abstraction that should be explored and possibly
exploited to provide a general pattern for working through these
situations. Since SQL, SPARQL, and R2RML are rule languages compatible
with relational algebra (RA), it should be possible to derive a common
set of RA predicates and classes to create an RDF vocabulary. This
vocabulary can then be used to write queries as production rules in a
generic standard rule language, such as RIF (Rule Interchange Format).
The RIF source can be translated to SQL, SPARQL, or R2RML for execution
in the target system.
Going from RIF to SQL, SPARQL, or R2RML is always going to be easier
than starting from SQL or SPARQL and going to some other format.
Theoretically you should be able to partially translate R2RML to RIF
automatically (SQL embedded in the R2RML will still be opaque). But I
don't know what tools could be used to translate SQL and SPARQL texts to
generic production rules using an RA vocabulary.
The ultimate payoff from this approach is that it will be possible to
link all of your data relations and operations with meaningful business
terminology and processes. It will enable greater visibility and control
of all data operations, and put important elements of business logic in
transparent rules (e.g. RIF) instead of arcane notations such as SQL
SPARQL (or worse, procedural code).
Regards,
--Paul
--
Dipl. Inf. Claus Stadler
Department of Computer Science, University of Leipzig
Research Group: http://aksw.org/
Workpage & WebID: http://aksw.org/ClausStadler
Phone: +49 341 97-32260
