- From: Sebastian Hellmann <hellmann@informatik.uni-leipzig.de>
- Date: Mon, 22 Apr 2013 12:40:36 +0200
- To: Daniel Garijo <dgarijo@fi.upm.es>
- CC: Prateek <prateek@knoesis.org>, "semantic-web@w3.org Web" <semantic-web@w3.org>
- Message-ID: <517513A4.9030308@informatik.uni-leipzig.de>
Ah, yes, you are right. Thanks for your help.
I was confused, because DBpedia also shows the instance data for the
classes in the HTML interface (i.e. inbound triples):
http://dbpedia.org/ontology/PopulatedPlace
But of course, this is just a nice add-on for the HTML view. There is
actually no "Get all instances of a class" via Linked Data, only via
SPARQL.
I have also updated
https://github.com/NLP2RDF/persistence.uni-leipzig.org#-vs--uris with:
> There has been an ongoing debate about '#' vs. '/' . We focus on
> ontologies with '\#' here with URIs like:
> http://persistence.uni-leipzig.org/nlp2rdf/ontologies/nif-core#String
> Note that ontologies with '/' URIs need to published differently
> (description not included here).
By the way, DBpedia only uses something that looks like Pubby, i.e. the
DBpedia VAD, which is written in vsp[1].
Thanks again,
Sebastian
[1]https://github.com/dbpedia/dbpedia-vad-i18n
Am 22.04.2013 12:17, schrieb Daniel Garijo:
> Hi, I'm not sure I see the issue here.
>
>
> 2013/4/22 Sebastian Hellmann <hellmann@informatik.uni-leipzig.de
> <mailto:hellmann@informatik.uni-leipzig.de>>
>
> Hm, no actually, this issue is quite easy, when it comes to large
> databases.
>
> curl -H "Accept: text/turtle"
> "http://dbpedia.org/ontology#PopulatedPlace"
> <http://dbpedia.org/ontology#PopulatedPlace>
> is pretty much the same as:
> curl -H "Accept: text/turtle" "http://dbpedia.org/ontology"
> <http://dbpedia.org/ontology>
>
> But here you are not asking for any instance. You are asking for a
> document
> where the ontology is defined.
>
>
> So my questions are:
>
> 1. What do you think is the expected output of
> http://dbpedia.org/ontology ? 300 million triples as turtle?
>
> No. You would see the description of the ontology. In DB-pedia they
> haven't done such redirection because
> they are exposing both terms and classes with Pubby. But note that
> when you look for a term, no instances
> are returned.
>
> 2. How do you query all instances of type db-ont:PopulatedPlace
> via Linked Data ?
>
> Via a SPARQL query:
> select ?instance where{
> ?instance a db-ont:PopulatedPlace.
> }
> If you don't want all the instances, then add a "LIMIT". That is why
> they have a public endpoint, right?
>
> Another example. The recent PROV-O Ontology (with namespace URI
> http://www.w3.org/ns/prov#).
> If I have an endpoint with many prov:Entities published and I want
> them, I can perform a query
> as the one I did above. If I want to see the documentation of the
> term, then I would ask for
> http://www.w3.org/ns/prov#Entity and I would be redirected to it.
> Doing an accept request for turtle to an ontology term would return
> the owl file of the ontology,
> not the instances of that term.
>
> Best,
> Daniel
>
>
> q.e.d from my point of view, as you wouldn't get around these
> practical problems.
>
> -- Sebastian
>
> Am 22.04.2013 11:50, schrieb Daniel Garijo:
>> Dear Sebastian,
>> This statement:
>> "When you publish ontologies without data, you can use '#' .
>> However, if you want to query instances via Linked Data in a
>> database, you have to use '/' as DBpedia does for classes:
>> http://dbpedia.org/ontology/PopulatedPlace"
>>
>> is not correct. You can use "#" to query instances via Linked
>> Data databases. That is just the URI of the type. In fact if
>> DBpedia had chosen
>>
>> "http://dbpedia.org/ontology#PopulatedPlace
>> <http://dbpedia.org/ontology/PopulatedPlace>" instead of its
>> current URI it would still be fine. It doesn't affect the query.
>>
>> I'm not going to enter in the debate of "# vs /", but normally it
>> is a design decission that has to do more with the size of
>> vocabularies than the
>> instances.
>>
>> Best,
>> Daniel
>>
>>
>>
>> 2013/4/22 Sebastian Hellmann <hellmann@informatik.uni-leipzig.de
>> <mailto:hellmann@informatik.uni-leipzig.de>>
>>
>> Dear all,
>>
>> personally, I have been working on this for quite a while and
>> for me the best and easiest way is as documented here:
>> https://github.com/NLP2RDF/persistence.uni-leipzig.org#readme
>>
>> They are simple and effective and I couldn't imagine anything
>> more.
>>
>> Note that I have also secured persistent hosting for the URIs
>> (also an important point).
>> Feedback welcome, of course.
>>
>> All the best,
>> Sebastian
>>
>>
>> Ontology:
>> http://persistence.uni-leipzig.org/nlp2rdf/ontologies/nif-core#
>>
>>
>> # vs /
>>
>> When you publish ontologies without data, you can use '#' .
>> However, if you want to query instances via Linked Data in a
>> database, you have to use '/' as DBpedia does for classes:
>> http://dbpedia.org/ontology/PopulatedPlace
>>
>>
>> <https://github.com/NLP2RDF/persistence.uni-leipzig.org#workflow>Workflow
>>
>> 1. I edit the ontologies in turtle syntax with the Geany
>> text editor (or a Turtle editor
>> http://blog.aksw.org/2013/xturtle-turtle-editing-the-eclipse-way
>> ), This allows me to make developers comments using "#"
>> directly in the source, see e.g.
>> nlp2rdf/ontologies/nif-core.ttl
>> 2. When I am finished I use rapper
>> (http://librdf.org/raptor/rapper.html) to convert it to
>> rdfxml ( nlp2rdf/ontologies/nif-core.owl )
>> 3. I am versioning the ontologies in a folder with the
>> version number, e.g. version-1.0 If somebody wants to
>> find old ontologies, she can find them in the GitHub
>> repository, which is linked from the ontology. I assume
>> this is not often required, but it is nice to keep old
>> versions. The old versions should be linked to in the
>> comment of the ontology, see the header of nif-core.ttl
>> 4. Then I use git push to push the changes to our server
>> 5. (not yet) I use a simple OWL2HTML generator, e.g.
>> https://github.com/specgen/specgen
>> 6. add yourself to http://prefix.cc, see e.g.
>> http://prefix.cc/nif
>> 7. The versions are switched and published by these
>> .htaccess rules, e.g. ||
>> |RewriteRule .(owl|rdf|html|ttl|nt|txt|md)$ - [L]
>> # (in progress) RewriteCond %{HTTP_ACCEPT} text/html
>> # (in progress) RewriteRule ^nif-core$
>> /nlp2rdf/ontologies/nif-core/version-1.0/nif-core.html
>> [R=303,L]
>>
>> RewriteCond %{HTTP_ACCEPT} application/rdf+xml
>> RewriteRule ^nif-core$
>> /nlp2rdf/ontologies/nif-core/version-1.0/nif-core.owl
>> [R=303,L]
>>
>> RewriteRule ^nif-core$
>> /nlp2rdf/ontologies/nif-core/version-1.0/nif-core.ttl
>> [R=303,L]|
>>
>>
>>
>>
>>
>>
>> Am 19.04.2013 16:05, schrieb Prateek:
>>> Hello all,
>>>
>>> I am trying to identify a system which will provide
>>> versioning and revision control capabilities specifically
>>> for ontologies. Does anyone have any experience and idea
>>> about which systems can help out or if systems like SVN, CVS
>>> can do the job?
>>>
>>> Regards
>>>
>>> Prateek
>>>
>>> --
>>>
>>> - - - - - - - - - - - - - - - - - - -
>>> Prateek Jain, Ph. D.
>>> RSM
>>> IBM T.J. Watson Research Center
>>> 1101 Kitchawan Road, 37-244
>>> Yorktown Heights, NY 10598
>>> Linkedin: http://www.linkedin.com/in/prateekj
>>>
>>
>>
>> --
>> Dipl. Inf. Sebastian Hellmann
>> Department of Computer Science, University of Leipzig
>> Projects: http://nlp2rdf.org , http://linguistics.okfn.org ,
>> http://dbpedia.org/Wiktionary , http://dbpedia.org
>> Homepage: http://bis.informatik.uni-leipzig.de/SebastianHellmann
>> Research Group: http://aksw.org
>>
>>
>
>
> --
> Dipl. Inf. Sebastian Hellmann
> Department of Computer Science, University of Leipzig
> Projects: http://nlp2rdf.org , http://linguistics.okfn.org ,
> http://dbpedia.org/Wiktionary , http://dbpedia.org
> Homepage: http://bis.informatik.uni-leipzig.de/SebastianHellmann
> Research Group: http://aksw.org
>
>
--
Dipl. Inf. Sebastian Hellmann
Department of Computer Science, University of Leipzig
Projects: http://nlp2rdf.org , http://linguistics.okfn.org ,
http://dbpedia.org/Wiktionary , http://dbpedia.org
Homepage: http://bis.informatik.uni-leipzig.de/SebastianHellmann
Research Group: http://aksw.org
Received on Monday, 22 April 2013 10:41:13 UTC