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RE: Generate r2rml mapping document

From: Barry Norton <BNorton@britishmuseum.org>
Date: Fri, 28 Mar 2014 12:01:54 +0000
To: Richard Cyganiak <richard@cyganiak.de>
CC: Katerin <kmrojas@estudiantes.uci.cu>, SW-forum Web <semantic-web@w3.org>
Message-ID: <F15EF6FB9C86824396BAD14E8BED119A3A3AD1@BLM-EXC-01.adbm.britishmuseum.org>
Thanks for the quick answer. I'll chase up on this offline.

You may recall that LinkedBrainz originally used 'native' D2RQ and indeed found 'virtual SPARQL endpoints' of insufficient performance, hence the ETL-based approach, which is now supported by extracting and transforming the postgresql data via R2RML and loading it into Virtuoso Open Source.



-----Original Message-----
From: Richard Cyganiak [mailto:richard@cyganiak.de] 
Sent: 28 March 2014 11:58
To: Barry Norton
Cc: Katerin; SW-forum Web
Subject: Re: Generate r2rml mapping document


The R2RML support is fairly complete, but not as well-tested as the rest of D2RQ.

The main missing feature is support for named graphs.

It works well for creating RDF dumps of the DB (using D2RQ's dump-rdf command). Virtual SPARQL endpoints over the DB *work*, but are very slow, as even fairly basic optimisations are still missing from the R2RML engine.


On 28 Mar 2014, at 11:50, Barry Norton <BNorton@britishmuseum.org> wrote:
> Richard, how complete now is the D2RQ implementation of R2RML 'execution' (enactment?) ?
> You may have caught MusicBrainz' announcement of RDF/SPARQL support 
> at: http://linkedbrainz.org/
> This mapping is effected using R2RML: 
> https://github.com/LinkedBrainz/MusicBrainz-R2RML
> and more than one RDB-mapping implementation is using these definitions for test, including Ultrawrap (used at MusicBrainz to produce the LinkedBrainz dump) and OBDA Semantika (see the latest 1.1.5 release notes).
> I'd be very keen to try out the mappings using D2RQ if this is now feasible.
> Cheers,
> Barry
> -----Original Message-----
> From: Richard Cyganiak [mailto:richard@cyganiak.de]
> Sent: 28 March 2014 11:41
> To: Katerin
> Cc: SW-forum Web
> Subject: Re: Generate r2rml mapping document
> Hi Katerin,
> The unreleased R2RML-compatible version of D2RQ can generate R2RML mappings from the schema of an existing database.
> You can find it as "d2rq-r2rml-preview-v4" here: 
> http://download.d2rq.org
> Use it like this:
>    ./generate-mapping --r2rml -u user -p password 
> jdbc:mysql://localhost/mydatabase
> There is (currently incomplete) documentation in the /doc directory of the download.
> The *very* latest version of that code, which may have more recent 
> bugfixes, is available in the project's "develop" branch on GitHub: 
> https://github.com/d2rq/d2rq
> Hope that helps,
> Richard
> On 21 Mar 2014, at 14:56, Katerin <kmrojas@estudiantes.uci.cu> wrote:
>> I'm using r2rml-parser and I need the mapping document to this. I 
>> have been searching for a tool that generate the r2rml mapping 
>> document but I didn't find it, if you know about some tool to this I will be thanks for it.
>> Regards, Katerin. 
Received on Saturday, 29 March 2014 22:11:18 UTC

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