Lucas,
No I don't need the page_id. The other two are enough.
Wikidata Query Service seems very slow (it'll take about one day of
continuous querying to get all the data). Linked Data Fragments server
seems faster, but I wish I knew how to make it return more than 100 results
at a time. Do you?
Thanks,
Huji
On Wed, Mar 14, 2018 at 7:00 AM, Lucas Werkmeister <
lucas.werkmeister(a)wikimedia.de> wrote:
Huji, do you need the page_id in the query
results? Otherwise, I would
suggest using either the Wikidata Query Service, as Jaime suggested (though
I’d omit the LIMIT and OFFSET – I think it’s better to let the server send
you all the results at once) or the Linked Data Fragments server:
https://query.wikidata.org/bigdata/ldf?subject=&predicate=ht
tp%3A%2F%2Fwww.wikidata.org%2Fprop%2Fdirect%2FP1566&object= (this URL
will return HTML, RDF XML, Turtle, LD-JSON, … depending on Accept header).
Cheers,
Lucas
2018-03-14 1:03 GMT+01:00 Huji Lee <huji.huji(a)gmail.com>om>:
> Thanks, Jaime, for your recommendation.
>
> If I understand the result of [1] correctly, there are around 3.5
> million pages with a GeoNames property specified on Wikidata. I'm sure some
> of them are redirects, or not cities, etc. But still, going through
> millions of pages through API calls of 1000 at a time is cumbersome and
> inefficient. (The example you gave takes 20 seconds to run; that would mean
> a total of 20 * 3.5 * 1000 seconds which is like 19 hours, assuming no lag
> or error).
>
> However, what you suggested gave me an idea: I can take a look at the
> code for the Api itself (I guess it is at [2]) and figure out how the query
> is written there, then try to write a similar query on my own. If I figure
> it out, I will report back here.
>
> Huji
>
> [1]
https://quarry.wmflabs.org/query/25418
> [2]
https://phabricator.wikimedia.org/diffusion/EWBA/browse/mast
> er/client/includes/Api/ApiPropsEntityUsage.php
>
> On Tue, Mar 13, 2018 at 5:39 AM, Jaime Crespo <jcrespo(a)wikimedia.org>
> wrote:
>
>> I am not 100% sure there is a perfect way to do what you want by
>> querying the metadata databases (I assume that is what you mean with
>> query)- I don't think that data is metadata, but content itself, which is
>> not on the metadata databases.
>>
>> Calling the wikidata query service is probably what you want:
>>
>> <https://query.wikidata.org/#SELECT%20%3Fitem%20%3FitemLabel
>> %20%3Fgeoname%0AWHERE%20%7B%0A%09%3Fitem%20wdt%3AP1566%20%3F
>> geoname%20.%0A%09SERVICE%20wikibase%3Alabel%20%7B%20bd%3Aser
>> viceParam%20wikibase%3Alanguage%20%22%5BAUTO_LANGUAGE%5D%2Ce
>> n%22%20%7D%0A%7D%0ALIMIT%201000%20OFFSET%201000>
>>
>> Note the LIMIT and OFFSET that will let you iterate over the dataset
>> (a where close would be faster).
>>
>> There is a way to get results, which is iterating over:
>> <https://www.wikidata.org/w/index.php?title=Special:WhatLink
>> sHere/Property:P1566&hidetrans=1&hideredirs=1>
>>
>> That is a standard mediawiki api query, you will also find this on
>> the pagelinks table, but you should check every page you get afterwards (by
>> retrieving its contents), as it could include false positives or be behind
>> on updates.
>>
>> On Sun, Mar 11, 2018 at 3:44 PM, Huji Lee <huji.huji(a)gmail.com>
>> wrote:
>>
>>> Hello,
>>>
>>> I need help writing a query that I would like to run on the Clouds.
>>> The goal of the query is to retrieve the following information from
>>> wikidatawiki_p:
>>>
>>> * Find all pages that have a claim for the property P1566, for
>>> example see
https://www.wikidata.org/wiki/Q2113430
>>> * Find out what is the value of their P1566 property (in this case,
>>> 18918)
>>>
>>> Output format should be like this:
>>>
>>> page_id entity property_value
>>> 2039804 Q2113430 18918
>>> ...
>>>
>>> Thanks in advance,
>>>
>>> Huji
>>>
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>>>
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>>>
>>
>>
>>
>> --
>> Jaime Crespo
>> <http://wikimedia.org>
>>
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>
>
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--
Lucas Werkmeister
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