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Posted to users@jena.apache.org by jani <ja...@gmail.com> on 2020/01/27 19:50:27 UTC
SPARQL-query to get data from wikidata not working
Hi everybody,
I try to get some image links from wikidata by running a SPARQL-query
from my local Jena Fuseki instance. I want to merge it with data from my
local graph. Unfortunately the query isn't delivering any data but runs
and runs instead without any error message.
The sparql-query:
|PREFIX owl: <http://www.w3.org/2002/07/owl#> PREFIX wd:
<http://www.wikidata.org/entity/> PREFIX wdt:
<http://www.wikidata.org/prop/direct/> PREFIX foaf:
<http://xmlns.com/foaf/0.1/> SELECT ?name ?image WHERE { ?s foaf:name
?name. ?s owl:sameAs ?wikidata_link. FILTER regex(str(?wikidata_link),
"wikidata"). SERVICE <https://query.wikidata.org/sparql> {
?wikidata_link wdt:P18 ?image. } } LIMIT 10 |
The test data I have in my local graph on the Jena Fuseki server:
|@base <http://dmt.de/pages> . @prefix rdf:
<http://www.w3.org/1999/02/22-rdf-syntax-ns#> . @prefix rdfs:
<http://www.w3.org/2000/01/rdf-schema#> . @prefix foaf:
<http://xmlns.com/foaf/0.1/> . @prefix dbp:
<http://dbpedia.org/resource/> . @prefix wd:
<https://www.wikidata.org/entity/> . @prefix owl:
<http://www.w3.org/2002/07/owl#> . <#john-cage> a foaf:Person ;
foaf:name "John Cage"; owl:sameAs dbp:John_Cage, wd:Q180727.
<#karlheinz-stockhausen> a foaf:Person ; foaf:name "Karlheinz
Stockhausen"; owl:sameAs dbp:Karlheinz_Stockhausen, wd:Q154556.
<#arnold-schoenberg> a foaf:Person; foaf:name "Arnold Schönberg";
owl:sameAs dbp:Arnold_Schoenberg, wd:Q154770. |
I tried a similar query for dbpedia-data which run perfectly.
|PREFIX owl: <http://www.w3.org/2002/07/owl#> PREFIX dbp:
<http://dbpedia.org/resource/> PREFIX foaf: <http://xmlns.com/foaf/0.1/>
PREFIX dbo: <http://dbpedia.org/ontology/> SELECT ?name ?dbpedia_link
?birthplace WHERE { ?s foaf:name ?name. ?s owl:sameAs ?dbpedia_link.
FILTER regex(str(?dbpedia_link),"dbpedia.org"). SERVICE
<https://dbpedia.org/sparql> { ?dbpedia_link dbo:birthPlace ?birthplace.
} } LIMIT 10 |
Any Ideas? Thanks in advance!
Jan Seipel
PS: also got this question on stackoverflow:
https://stackoverflow.com/questions/59937684/sparql-query-to-get-data-from-wikidata-not-working
Re: SPARQL-query to get data from wikidata not working
Posted by "Lorenz B." <bu...@informatik.uni-leipzig.de>.
Comments and debugging notes inline
On 1/28/20 9:58 AM, Andy Seaborne wrote:
>
>
> On 28/01/2020 07:50, Lorenz Buehmann wrote:
>> Yes, the intermediate result is large, I tried it on CLI:
>>
>> |bin/rsparql --service https://query.wikidata.org/sparql "select *
>> {?wikidata_link <|||http://www.wikidata.org/prop/direct/|P18> ?image}" >
>> /tmp/res.sparql|
>>
>> |It will most likely lead to an OOM error - unless your increase the JVM
>> heap memory. It's because either a large JSON or XML object will be
>> returned here and has to be parsed resp. processed.|
>
> Then one possibility is it is pushing the Fuseki query execution into
> GC overload. It is possible that teh GC is working very hard and
> making minimal progress only to be triggered again for a full-GC. The
> fuseki start-up script sets the JVM heap size but not to a huge
> amount. 3 million rows might trigger GC problems. You can override it
> with JVM_ARGS.
Yep, might be a reason as also commented on SO post. Would be
interesting to see more from the Fuseki logs. Running 1h without any
exception might indicate this GC thing but still seems to be somehow
unexpected - even for 3 million rows, which is large but nowadays not
really considered as huge.
>
>>
>> |The subquery hint from Andy is a nice workaround, but indeed you would
>> get only partial results - this might not contain the Wikidata resources
>> from your dataset, thus, the result would be incomplete or even empty.
>> |
>>
>
> The thing is that SERVICE used to execute the other way - sending
> several small requests. Except that causes other problems when the
> query has a large number of possibilities to try from earlier in the
> query.
So it's using bindings from the "outer" query, i.e. inlining data,
right? I remember somebody was suggesting to improve this via a more
smart batch approach, i.e. to reduce the number of request to the remote
service. Is this already integrated and can even be configured somehow?
Anyways, ahd more time now and tried the initial query with the given
data which in fact just contains 3 Wikidata resources. It finishes
instantly with an empty result. I also set log level to ALL, thus, I can
confirm exactly 3 requests like
SELECT *
WHERE
{ <https://www.wikidata.org/entity/Q180727>
<http://www.wikidata.org/prop/direct/P18> ?image
}
to the Wikidata service. That means, everything as Andy said, single
requests will be send to Wikidata.
So my question, why would this not work in Fuseki? That sounds weird
with this tiny dataset and just 3 single requests. Unless, the real
dataset is much larger and would lead to millions of single requests to
Wikidata ...
By the way, the result is empty because the Wikidata URIs in the dataset
are wrong, the URIs must not start with https but http only.
>
> GC thrashing sounds possible.
>
> Andy
>
>> |
>> |
>>
>> On 27.01.20 23:47, Andy Seaborne wrote:
>>> The query will try to pull a lot of data from
>>> query.wikidata.org/sparql.
>>>
>>> (see comments on the SO query)
>>>
>>> What might help is to write a subselect with LIMIT inside the SERVICE
>>> and put a limit on that. That pushes a LIMIT to the far end which, as
>>> written, does not happen.
>>>
>>> Andy
>>>
>>> On 27/01/2020 19:50, jani wrote:
>>>> Hi everybody,
>>>>
>>>> I try to get some image links from wikidata by running a SPARQL-query
>>>> from my local Jena Fuseki instance. I want to merge it with data from
>>>> my local graph. Unfortunately the query isn't delivering any data but
>>>> runs and runs instead without any error message.
>>>>
>>>> The sparql-query:
>>>>
>>>> |PREFIX owl: <http://www.w3.org/2002/07/owl#> PREFIX wd:
>>>> <http://www.wikidata.org/entity/> PREFIX wdt:
>>>> <http://www.wikidata.org/prop/direct/> PREFIX foaf:
>>>> <http://xmlns.com/foaf/0.1/> SELECT ?name ?image WHERE { ?s foaf:name
>>>> ?name. ?s owl:sameAs ?wikidata_link. FILTER
>>>> regex(str(?wikidata_link), "wikidata"). SERVICE
>>>> <https://query.wikidata.org/sparql> { ?wikidata_link wdt:P18 ?image.
>>>> } } LIMIT 10 |
>>>>
>>>> The test data I have in my local graph on the Jena Fuseki server:
>>>>
>>>> |@base <http://dmt.de/pages> . @prefix rdf:
>>>> <http://www.w3.org/1999/02/22-rdf-syntax-ns#> . @prefix rdfs:
>>>> <http://www.w3.org/2000/01/rdf-schema#> . @prefix foaf:
>>>> <http://xmlns.com/foaf/0.1/> . @prefix dbp:
>>>> <http://dbpedia.org/resource/> . @prefix wd:
>>>> <https://www.wikidata.org/entity/> . @prefix owl:
>>>> <http://www.w3.org/2002/07/owl#> . <#john-cage> a foaf:Person ;
>>>> foaf:name "John Cage"; owl:sameAs dbp:John_Cage, wd:Q180727.
>>>> <#karlheinz-stockhausen> a foaf:Person ; foaf:name "Karlheinz
>>>> Stockhausen"; owl:sameAs dbp:Karlheinz_Stockhausen, wd:Q154556.
>>>> <#arnold-schoenberg> a foaf:Person; foaf:name "Arnold Schönberg";
>>>> owl:sameAs dbp:Arnold_Schoenberg, wd:Q154770. |
>>>>
>>>> I tried a similar query for dbpedia-data which run perfectly.
>>>>
>>>> |PREFIX owl: <http://www.w3.org/2002/07/owl#> PREFIX dbp:
>>>> <http://dbpedia.org/resource/> PREFIX foaf:
>>>> <http://xmlns.com/foaf/0.1/> PREFIX dbo:
>>>> <http://dbpedia.org/ontology/> SELECT ?name ?dbpedia_link ?birthplace
>>>> WHERE { ?s foaf:name ?name. ?s owl:sameAs ?dbpedia_link. FILTER
>>>> regex(str(?dbpedia_link),"dbpedia.org"). SERVICE
>>>> <https://dbpedia.org/sparql> { ?dbpedia_link dbo:birthPlace
>>>> ?birthplace. } } LIMIT 10 |
>>>>
>>>> Any Ideas? Thanks in advance!
>>>>
>>>> Jan Seipel
>>>>
>>>> PS: also got this question on stackoverflow:
>>>> https://stackoverflow.com/questions/59937684/sparql-query-to-get-data-from-wikidata-not-working
>>>>
>>>>
>>>>
>>>>
>>
--
Lorenz Bühmann
AKSW group, University of Leipzig
Group: http://aksw.org - semantic web research center
Re: SPARQL-query to get data from wikidata not working
Posted by Andy Seaborne <an...@apache.org>.
On 28/01/2020 07:50, Lorenz Buehmann wrote:
> Yes, the intermediate result is large, I tried it on CLI:
>
> |bin/rsparql --service https://query.wikidata.org/sparql "select *
> {?wikidata_link <|||http://www.wikidata.org/prop/direct/|P18> ?image}" >
> /tmp/res.sparql|
>
> |It will most likely lead to an OOM error - unless your increase the JVM
> heap memory. It's because either a large JSON or XML object will be
> returned here and has to be parsed resp. processed.|
Then one possibility is it is pushing the Fuseki query execution into GC
overload. It is possible that teh GC is working very hard and making
minimal progress only to be triggered again for a full-GC. The fuseki
start-up script sets the JVM heap size but not to a huge amount. 3
million rows might trigger GC problems. You can override it with
JVM_ARGS.
>
> |The subquery hint from Andy is a nice workaround, but indeed you would
> get only partial results - this might not contain the Wikidata resources
> from your dataset, thus, the result would be incomplete or even empty.
> |
>
The thing is that SERVICE used to execute the other way - sending
several small requests. Except that causes other problems when the
query has a large number of possibilities to try from earlier in the query.
GC thrashing sounds possible.
Andy
> |
> |
>
> On 27.01.20 23:47, Andy Seaborne wrote:
>> The query will try to pull a lot of data from query.wikidata.org/sparql.
>>
>> (see comments on the SO query)
>>
>> What might help is to write a subselect with LIMIT inside the SERVICE
>> and put a limit on that. That pushes a LIMIT to the far end which, as
>> written, does not happen.
>>
>> Andy
>>
>> On 27/01/2020 19:50, jani wrote:
>>> Hi everybody,
>>>
>>> I try to get some image links from wikidata by running a SPARQL-query
>>> from my local Jena Fuseki instance. I want to merge it with data from
>>> my local graph. Unfortunately the query isn't delivering any data but
>>> runs and runs instead without any error message.
>>>
>>> The sparql-query:
>>>
>>> |PREFIX owl: <http://www.w3.org/2002/07/owl#> PREFIX wd:
>>> <http://www.wikidata.org/entity/> PREFIX wdt:
>>> <http://www.wikidata.org/prop/direct/> PREFIX foaf:
>>> <http://xmlns.com/foaf/0.1/> SELECT ?name ?image WHERE { ?s foaf:name
>>> ?name. ?s owl:sameAs ?wikidata_link. FILTER
>>> regex(str(?wikidata_link), "wikidata"). SERVICE
>>> <https://query.wikidata.org/sparql> { ?wikidata_link wdt:P18 ?image.
>>> } } LIMIT 10 |
>>>
>>> The test data I have in my local graph on the Jena Fuseki server:
>>>
>>> |@base <http://dmt.de/pages> . @prefix rdf:
>>> <http://www.w3.org/1999/02/22-rdf-syntax-ns#> . @prefix rdfs:
>>> <http://www.w3.org/2000/01/rdf-schema#> . @prefix foaf:
>>> <http://xmlns.com/foaf/0.1/> . @prefix dbp:
>>> <http://dbpedia.org/resource/> . @prefix wd:
>>> <https://www.wikidata.org/entity/> . @prefix owl:
>>> <http://www.w3.org/2002/07/owl#> . <#john-cage> a foaf:Person ;
>>> foaf:name "John Cage"; owl:sameAs dbp:John_Cage, wd:Q180727.
>>> <#karlheinz-stockhausen> a foaf:Person ; foaf:name "Karlheinz
>>> Stockhausen"; owl:sameAs dbp:Karlheinz_Stockhausen, wd:Q154556.
>>> <#arnold-schoenberg> a foaf:Person; foaf:name "Arnold Schönberg";
>>> owl:sameAs dbp:Arnold_Schoenberg, wd:Q154770. |
>>>
>>> I tried a similar query for dbpedia-data which run perfectly.
>>>
>>> |PREFIX owl: <http://www.w3.org/2002/07/owl#> PREFIX dbp:
>>> <http://dbpedia.org/resource/> PREFIX foaf:
>>> <http://xmlns.com/foaf/0.1/> PREFIX dbo:
>>> <http://dbpedia.org/ontology/> SELECT ?name ?dbpedia_link ?birthplace
>>> WHERE { ?s foaf:name ?name. ?s owl:sameAs ?dbpedia_link. FILTER
>>> regex(str(?dbpedia_link),"dbpedia.org"). SERVICE
>>> <https://dbpedia.org/sparql> { ?dbpedia_link dbo:birthPlace
>>> ?birthplace. } } LIMIT 10 |
>>>
>>> Any Ideas? Thanks in advance!
>>>
>>> Jan Seipel
>>>
>>> PS: also got this question on stackoverflow:
>>> https://stackoverflow.com/questions/59937684/sparql-query-to-get-data-from-wikidata-not-working
>>>
>>>
>>>
>
Re: SPARQL-query to get data from wikidata not working
Posted by Lorenz Buehmann <bu...@informatik.uni-leipzig.de>.
Yes, the intermediate result is large, I tried it on CLI:
|bin/rsparql --service https://query.wikidata.org/sparql "select *
{?wikidata_link <|||http://www.wikidata.org/prop/direct/|P18> ?image}" >
/tmp/res.sparql|
|It will most likely lead to an OOM error - unless your increase the JVM
heap memory. It's because either a large JSON or XML object will be
returned here and has to be parsed resp. processed.|
|The subquery hint from Andy is a nice workaround, but indeed you would
get only partial results - this might not contain the Wikidata resources
from your dataset, thus, the result would be incomplete or even empty.
|
|
|
On 27.01.20 23:47, Andy Seaborne wrote:
> The query will try to pull a lot of data from query.wikidata.org/sparql.
>
> (see comments on the SO query)
>
> What might help is to write a subselect with LIMIT inside the SERVICE
> and put a limit on that. That pushes a LIMIT to the far end which, as
> written, does not happen.
>
> Andy
>
> On 27/01/2020 19:50, jani wrote:
>> Hi everybody,
>>
>> I try to get some image links from wikidata by running a SPARQL-query
>> from my local Jena Fuseki instance. I want to merge it with data from
>> my local graph. Unfortunately the query isn't delivering any data but
>> runs and runs instead without any error message.
>>
>> The sparql-query:
>>
>> |PREFIX owl: <http://www.w3.org/2002/07/owl#> PREFIX wd:
>> <http://www.wikidata.org/entity/> PREFIX wdt:
>> <http://www.wikidata.org/prop/direct/> PREFIX foaf:
>> <http://xmlns.com/foaf/0.1/> SELECT ?name ?image WHERE { ?s foaf:name
>> ?name. ?s owl:sameAs ?wikidata_link. FILTER
>> regex(str(?wikidata_link), "wikidata"). SERVICE
>> <https://query.wikidata.org/sparql> { ?wikidata_link wdt:P18 ?image.
>> } } LIMIT 10 |
>>
>> The test data I have in my local graph on the Jena Fuseki server:
>>
>> |@base <http://dmt.de/pages> . @prefix rdf:
>> <http://www.w3.org/1999/02/22-rdf-syntax-ns#> . @prefix rdfs:
>> <http://www.w3.org/2000/01/rdf-schema#> . @prefix foaf:
>> <http://xmlns.com/foaf/0.1/> . @prefix dbp:
>> <http://dbpedia.org/resource/> . @prefix wd:
>> <https://www.wikidata.org/entity/> . @prefix owl:
>> <http://www.w3.org/2002/07/owl#> . <#john-cage> a foaf:Person ;
>> foaf:name "John Cage"; owl:sameAs dbp:John_Cage, wd:Q180727.
>> <#karlheinz-stockhausen> a foaf:Person ; foaf:name "Karlheinz
>> Stockhausen"; owl:sameAs dbp:Karlheinz_Stockhausen, wd:Q154556.
>> <#arnold-schoenberg> a foaf:Person; foaf:name "Arnold Schönberg";
>> owl:sameAs dbp:Arnold_Schoenberg, wd:Q154770. |
>>
>> I tried a similar query for dbpedia-data which run perfectly.
>>
>> |PREFIX owl: <http://www.w3.org/2002/07/owl#> PREFIX dbp:
>> <http://dbpedia.org/resource/> PREFIX foaf:
>> <http://xmlns.com/foaf/0.1/> PREFIX dbo:
>> <http://dbpedia.org/ontology/> SELECT ?name ?dbpedia_link ?birthplace
>> WHERE { ?s foaf:name ?name. ?s owl:sameAs ?dbpedia_link. FILTER
>> regex(str(?dbpedia_link),"dbpedia.org"). SERVICE
>> <https://dbpedia.org/sparql> { ?dbpedia_link dbo:birthPlace
>> ?birthplace. } } LIMIT 10 |
>>
>> Any Ideas? Thanks in advance!
>>
>> Jan Seipel
>>
>> PS: also got this question on stackoverflow:
>> https://stackoverflow.com/questions/59937684/sparql-query-to-get-data-from-wikidata-not-working
>>
>>
>>
Re: SPARQL-query to get data from wikidata not working
Posted by Andy Seaborne <an...@apache.org>.
The query will try to pull a lot of data from query.wikidata.org/sparql.
(see comments on the SO query)
What might help is to write a subselect with LIMIT inside the SERVICE
and put a limit on that. That pushes a LIMIT to the far end which, as
written, does not happen.
Andy
On 27/01/2020 19:50, jani wrote:
> Hi everybody,
>
> I try to get some image links from wikidata by running a SPARQL-query
> from my local Jena Fuseki instance. I want to merge it with data from my
> local graph. Unfortunately the query isn't delivering any data but runs
> and runs instead without any error message.
>
> The sparql-query:
>
> |PREFIX owl: <http://www.w3.org/2002/07/owl#> PREFIX wd:
> <http://www.wikidata.org/entity/> PREFIX wdt:
> <http://www.wikidata.org/prop/direct/> PREFIX foaf:
> <http://xmlns.com/foaf/0.1/> SELECT ?name ?image WHERE { ?s foaf:name
> ?name. ?s owl:sameAs ?wikidata_link. FILTER regex(str(?wikidata_link),
> "wikidata"). SERVICE <https://query.wikidata.org/sparql> {
> ?wikidata_link wdt:P18 ?image. } } LIMIT 10 |
>
> The test data I have in my local graph on the Jena Fuseki server:
>
> |@base <http://dmt.de/pages> . @prefix rdf:
> <http://www.w3.org/1999/02/22-rdf-syntax-ns#> . @prefix rdfs:
> <http://www.w3.org/2000/01/rdf-schema#> . @prefix foaf:
> <http://xmlns.com/foaf/0.1/> . @prefix dbp:
> <http://dbpedia.org/resource/> . @prefix wd:
> <https://www.wikidata.org/entity/> . @prefix owl:
> <http://www.w3.org/2002/07/owl#> . <#john-cage> a foaf:Person ;
> foaf:name "John Cage"; owl:sameAs dbp:John_Cage, wd:Q180727.
> <#karlheinz-stockhausen> a foaf:Person ; foaf:name "Karlheinz
> Stockhausen"; owl:sameAs dbp:Karlheinz_Stockhausen, wd:Q154556.
> <#arnold-schoenberg> a foaf:Person; foaf:name "Arnold Schönberg";
> owl:sameAs dbp:Arnold_Schoenberg, wd:Q154770. |
>
> I tried a similar query for dbpedia-data which run perfectly.
>
> |PREFIX owl: <http://www.w3.org/2002/07/owl#> PREFIX dbp:
> <http://dbpedia.org/resource/> PREFIX foaf: <http://xmlns.com/foaf/0.1/>
> PREFIX dbo: <http://dbpedia.org/ontology/> SELECT ?name ?dbpedia_link
> ?birthplace WHERE { ?s foaf:name ?name. ?s owl:sameAs ?dbpedia_link.
> FILTER regex(str(?dbpedia_link),"dbpedia.org"). SERVICE
> <https://dbpedia.org/sparql> { ?dbpedia_link dbo:birthPlace ?birthplace.
> } } LIMIT 10 |
>
> Any Ideas? Thanks in advance!
>
> Jan Seipel
>
> PS: also got this question on stackoverflow:
> https://stackoverflow.com/questions/59937684/sparql-query-to-get-data-from-wikidata-not-working
>
>
>
Re: SPARQL-query to get data from wikidata not working
Posted by Jan Seipel <ja...@gmail.com>.
@Lorenz Thanks for the hint! I'll try it this evening and reply to you if
it works. Would be nice if this is the solution.
Best Jan
Lorenz Buehmann <bu...@informatik.uni-leipzig.de> schrieb am Mi., 29.
Jan. 2020, 10:06:
> Just as a follow up to my previous message. I tried it with a local
> Fuseki and it works fine with the given test data - the only thing I
> changed, and also mentioned in my previous response, the namespace
> declaration of wd: is wrong, must be http: not https:
>
> 3 rows are returned as expected instantly.
>
> @Jan: so, do you use a larger dataset? I don't see why it would fail
> with this tiny dataset containing 12 triples on just 3 Wikidata
> entities. I doubt your query runs forever, I think it's just empty
> because of the namespace issue in the data.
>
>
> On 27.01.20 20:50, jani wrote:
> > Hi everybody,
> >
> > I try to get some image links from wikidata by running a SPARQL-query
> > from my local Jena Fuseki instance. I want to merge it with data from
> > my local graph. Unfortunately the query isn't delivering any data but
> > runs and runs instead without any error message.
> >
> > The sparql-query:
> >
> > |PREFIX owl: <http://www.w3.org/2002/07/owl#> PREFIX wd:
> > <http://www.wikidata.org/entity/> PREFIX wdt:
> > <http://www.wikidata.org/prop/direct/> PREFIX foaf:
> > <http://xmlns.com/foaf/0.1/> SELECT ?name ?image WHERE { ?s foaf:name
> > ?name. ?s owl:sameAs ?wikidata_link. FILTER regex(str(?wikidata_link),
> > "wikidata"). SERVICE <https://query.wikidata.org/sparql> {
> > ?wikidata_link wdt:P18 ?image. } } LIMIT 10 |
> >
> > The test data I have in my local graph on the Jena Fuseki server:
> >
> > |@base <http://dmt.de/pages> . @prefix rdf:
> > <http://www.w3.org/1999/02/22-rdf-syntax-ns#> . @prefix rdfs:
> > <http://www.w3.org/2000/01/rdf-schema#> . @prefix foaf:
> > <http://xmlns.com/foaf/0.1/> . @prefix dbp:
> > <http://dbpedia.org/resource/> . @prefix wd:
> > <https://www.wikidata.org/entity/> . @prefix owl:
> > <http://www.w3.org/2002/07/owl#> . <#john-cage> a foaf:Person ;
> > foaf:name "John Cage"; owl:sameAs dbp:John_Cage, wd:Q180727.
> > <#karlheinz-stockhausen> a foaf:Person ; foaf:name "Karlheinz
> > Stockhausen"; owl:sameAs dbp:Karlheinz_Stockhausen, wd:Q154556.
> > <#arnold-schoenberg> a foaf:Person; foaf:name "Arnold Schönberg";
> > owl:sameAs dbp:Arnold_Schoenberg, wd:Q154770. |
> >
> > I tried a similar query for dbpedia-data which run perfectly.
> >
> > |PREFIX owl: <http://www.w3.org/2002/07/owl#> PREFIX dbp:
> > <http://dbpedia.org/resource/> PREFIX foaf:
> > <http://xmlns.com/foaf/0.1/> PREFIX dbo:
> > <http://dbpedia.org/ontology/> SELECT ?name ?dbpedia_link ?birthplace
> > WHERE { ?s foaf:name ?name. ?s owl:sameAs ?dbpedia_link. FILTER
> > regex(str(?dbpedia_link),"dbpedia.org"). SERVICE
> > <https://dbpedia.org/sparql> { ?dbpedia_link dbo:birthPlace
> > ?birthplace. } } LIMIT 10 |
> >
> > Any Ideas? Thanks in advance!
> >
> > Jan Seipel
> >
> > PS: also got this question on stackoverflow:
> >
> https://stackoverflow.com/questions/59937684/sparql-query-to-get-data-from-wikidata-not-working
> >
> >
>
Re: SPARQL-query to get data from wikidata not working
Posted by Lorenz Buehmann <bu...@informatik.uni-leipzig.de>.
Just as a follow up to my previous message. I tried it with a local
Fuseki and it works fine with the given test data - the only thing I
changed, and also mentioned in my previous response, the namespace
declaration of wd: is wrong, must be http: not https:
3 rows are returned as expected instantly.
@Jan: so, do you use a larger dataset? I don't see why it would fail
with this tiny dataset containing 12 triples on just 3 Wikidata
entities. I doubt your query runs forever, I think it's just empty
because of the namespace issue in the data.
On 27.01.20 20:50, jani wrote:
> Hi everybody,
>
> I try to get some image links from wikidata by running a SPARQL-query
> from my local Jena Fuseki instance. I want to merge it with data from
> my local graph. Unfortunately the query isn't delivering any data but
> runs and runs instead without any error message.
>
> The sparql-query:
>
> |PREFIX owl: <http://www.w3.org/2002/07/owl#> PREFIX wd:
> <http://www.wikidata.org/entity/> PREFIX wdt:
> <http://www.wikidata.org/prop/direct/> PREFIX foaf:
> <http://xmlns.com/foaf/0.1/> SELECT ?name ?image WHERE { ?s foaf:name
> ?name. ?s owl:sameAs ?wikidata_link. FILTER regex(str(?wikidata_link),
> "wikidata"). SERVICE <https://query.wikidata.org/sparql> {
> ?wikidata_link wdt:P18 ?image. } } LIMIT 10 |
>
> The test data I have in my local graph on the Jena Fuseki server:
>
> |@base <http://dmt.de/pages> . @prefix rdf:
> <http://www.w3.org/1999/02/22-rdf-syntax-ns#> . @prefix rdfs:
> <http://www.w3.org/2000/01/rdf-schema#> . @prefix foaf:
> <http://xmlns.com/foaf/0.1/> . @prefix dbp:
> <http://dbpedia.org/resource/> . @prefix wd:
> <https://www.wikidata.org/entity/> . @prefix owl:
> <http://www.w3.org/2002/07/owl#> . <#john-cage> a foaf:Person ;
> foaf:name "John Cage"; owl:sameAs dbp:John_Cage, wd:Q180727.
> <#karlheinz-stockhausen> a foaf:Person ; foaf:name "Karlheinz
> Stockhausen"; owl:sameAs dbp:Karlheinz_Stockhausen, wd:Q154556.
> <#arnold-schoenberg> a foaf:Person; foaf:name "Arnold Schönberg";
> owl:sameAs dbp:Arnold_Schoenberg, wd:Q154770. |
>
> I tried a similar query for dbpedia-data which run perfectly.
>
> |PREFIX owl: <http://www.w3.org/2002/07/owl#> PREFIX dbp:
> <http://dbpedia.org/resource/> PREFIX foaf:
> <http://xmlns.com/foaf/0.1/> PREFIX dbo:
> <http://dbpedia.org/ontology/> SELECT ?name ?dbpedia_link ?birthplace
> WHERE { ?s foaf:name ?name. ?s owl:sameAs ?dbpedia_link. FILTER
> regex(str(?dbpedia_link),"dbpedia.org"). SERVICE
> <https://dbpedia.org/sparql> { ?dbpedia_link dbo:birthPlace
> ?birthplace. } } LIMIT 10 |
>
> Any Ideas? Thanks in advance!
>
> Jan Seipel
>
> PS: also got this question on stackoverflow:
> https://stackoverflow.com/questions/59937684/sparql-query-to-get-data-from-wikidata-not-working
>
>