4 ms·

Where do you end up with the translations from wdt:P25 to "mother"? That's the most incomprehensible part. It feels like I need a reverse dictionary lookup to w

Where do you end up with the translations from wdt:P25 to "mother"? That's the most incomprehensible part. It feels like I need a reverse dictionary lookup to write a single query.

tasogare 5y ago
Yep. Not only this but in the sample "wd:Q9682" is a lie. wd is a namespace shortcut which is expended to an URI, and the prefix to URI mapping has to be defined as part of the query, otherwise it won't work. Notice how the sample use two of those prefixes (wd and wdt): data is segregated in different namespace that one have to search for and remember each time they want to make a query. And I mean remembering the prefix value, ie a partial URI, not the little cute prefix like wd that semweb sample always use.
- bawolff 5y ago
  The sparql endpoint that is typically used with wikidata has some namespaces implicitly predefined, including wdt and wd. You do not need to declare the wd: prefix if you are using the endpoint at https://query.wikidata.org https://query.wikidata.org I think its safe to assume in context that the newbie sparql user is not setting up their own sparql endpoint but using the official wikidata endpoint.
bawolff 5y ago
I 100% agree that namespaces, urls and numeric Q ids add significantly to how complex wikidata sparql queries are, and generally make them incomprehensible. The editor at https://query.wikidata.org https://query.wikidata.org does have helpful tooltips though. But honestly i think people would have a lot easier time if we had less indirection and just wrote "mother" instead of wdt:P25 What i actually do, is take the number, if it starts with a q go to wikidata.org/wiki/Q123 . If it starts with P go to https://wikidata.org/wiki/Property:P25 https://wikidata.org/wiki/Property:P25 What it actually means in a technical sense: Identifiers in sparql are urls (sort of similar to integer id fields in sql). wdt: is short for http://wikidata.org/prop/direct http://wikidata.org/prop/direct so wdt:P25 is http://wikidata.org/prop/direct/P25 http://wikidata.org/prop/direct/P25 wdt: means basically normalized but there are other prefixes if you need to access deprectated statements or modifiers on properties. Gory details at https://www.mediawiki.org/wiki/Wikibase/Indexing/RDF_Dump_Format#Prefixes_used https://www.mediawiki.org/wiki/Wikibase/Indexing/RDF_Dump_Fo...
Lockal 5y ago
Btw, if you are using https://query.wikidata.org https://query.wikidata.org, you can type: wdt:mother, press ctrl+space and it will suggest P25 relationship.
lolive 5y ago
It’s part of the Wikidata data model.

Where do you end up with the translations from wdt:P25 to "mother"? That's the most incomprehensible part. It feels like I need a reverse dictionary lookup to write a single query.

tasogare 5y ago

Yep. Not only this but in the sample "wd:Q9682" is a lie. wd is a namespace shortcut which is expended to an URI, and the prefix to URI mapping has to be defined as part of the query, otherwise it won't work. Notice how the sample use two of those prefixes (wd and wdt): data is segregated in different namespace that one have to search for and remember each time they want to make a query. And I mean remembering the prefix value, ie a partial URI, not the little cute prefix like wd that semweb sample always use.

bawolff 5y ago
The sparql endpoint that is typically used with wikidata has some namespaces implicitly predefined, including wdt and wd. You do not need to declare the wd: prefix if you are using the endpoint at https://query.wikidata.org https://query.wikidata.org I think its safe to assume in context that the newbie sparql user is not setting up their own sparql endpoint but using the official wikidata endpoint.

bawolff 5y ago

I 100% agree that namespaces, urls and numeric Q ids add significantly to how complex wikidata sparql queries are, and generally make them incomprehensible. The editor at https://query.wikidata.org https://query.wikidata.org does have helpful tooltips though. But honestly i think people would have a lot easier time if we had less indirection and just wrote "mother" instead of wdt:P25 What i actually do, is take the number, if it starts with a q go to wikidata.org/wiki/Q123 . If it starts with P go to https://wikidata.org/wiki/Property:P25 https://wikidata.org/wiki/Property:P25 What it actually means in a technical sense: Identifiers in sparql are urls (sort of similar to integer id fields in sql). wdt: is short for http://wikidata.org/prop/direct http://wikidata.org/prop/direct so wdt:P25 is http://wikidata.org/prop/direct/P25 http://wikidata.org/prop/direct/P25 wdt: means basically normalized but there are other prefixes if you need to access deprectated statements or modifiers on properties. Gory details at https://www.mediawiki.org/wiki/Wikibase/Indexing/RDF_Dump_Format#Prefixes_used https://www.mediawiki.org/wiki/Wikibase/Indexing/RDF_Dump_Fo...

Lockal 5y ago

Btw, if you are using https://query.wikidata.org https://query.wikidata.org, you can type: wdt:mother, press ctrl+space and it will suggest P25 relationship.

lolive 5y ago

It’s part of the Wikidata data model.