Support transitive queries
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	• bzimport
	Jul 7 2013, 10:57 PM

Description

Author: emw.wiki

Description:
Transitive properties have wide use in Wikidata. Examples include basic membership properties like instance of (P31), subclass of (P279) and part of (P361); and genealogical properties like mother and father. The P31 and P279 properties are based on W3C recommendations for representing information in the Semantic Web -- rdf:type and rdfs:subClassOf.

The ability to draw conclusions from transitive properties is possible with RDFS query inference engines that implement SPARQL. A list of SPARQL implementations is available at http://www.w3.org/wiki/SparqlImplementations. Handling the simple entailments implied by P31 and P279 seems to be a core feature of querying in the Semantic Web.

http://meta.wikimedia.org/wiki/Wikidata/Technical_proposal#Optional_extensions_to_phase_3 mentions the first optional goal as "Develop and prepare a SPARQL endpoint to the data". While support for transitive properties presumably (and understandably) would not be part of Wikidata's initial support for SPARQL, a bit down the line it would be very helpful to have support for general transitive properties in Wikidata SPARQL queries, or at least the more limited and core feature of handling inferred claims for the rdf:type and rdfs:subClassOf (P31 and P279) properties.

Magnus Manske has also inquired about support for this kind of feature in http://meta.wikimedia.org/wiki/Talk:Wikidata/Development/Queries. An earlier version of this feature request is available at http://www.wikidata.org/wiki/Wikidata:Contact_the_development_team/Archive/2013/04#Transitive_properties_and_SPARQL.

There are important details that would need to be worked out with conflicting sources and qualifiers, but I'm filing this here so there's a place to track this feature request at a high level.

Version: unspecified
Severity: enhancement

Details

Reference: bz50911

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Status	Assigned	Task
Resolved	None	T52911 Support transitive queries
Declined	Lydia_Pintscher	T54385 Query by one property and one value ("simple queries") (tracking)
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Resolved	None	T58094 Setup, and test simple query functionality on internal test system
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Invalid	Lydia_Pintscher	T66605 Investigate if we can use "continue" instead of "offset" for EntitiesByPropertyValue API
Resolved	None	T65608 Decide on limit and offset limits for EntitiesByPropertyValue API
Resolved	None	T68421 Create script that generates schema creation SQL
Resolved	None	T66895 consider deprecated and preferred rank in queries
Resolved	None	T65476 Add DVHandler for Time values
Invalid	Lydia_Pintscher	T65477 Actually support novalue and somevalue snaks in queries (tracking)
Declined	None	T68423 Implement support for somevalue and novalue snaks in the API module
Declined	None	T68424 Implement support for novalue and somevalue snaks in the simple query SpecialPage
Duplicate	None	T68422 Support for novalue and somevalue snaks in WikibaseQuery
Resolved	None	T62127 Implement DB schema for query indexes
Resolved	None	T58095 writing a proposal for query database schema
Invalid	Lydia_Pintscher	T69080 [Story] Implement range queries for uncertain values (geo, time, quantities)
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Invalid	Lydia_Pintscher	T69534 performance review of WikibaseQuery
Invalid	Lydia_Pintscher	T69535 performance review of WikibaseQueryEngine
Invalid	• csteipp	T69536 security review of WikibaseQueryEngine
Invalid	• csteipp	T69533 security review of WikibaseQuery
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Invalid	Lydia_Pintscher	T73501 [Task] Update QueryEngine to use WB DB again
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Invalid	Lydia_Pintscher	T78656 [RFC] DBAL vs MW's DatabaseBase
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Invalid	thiemowmde	T73505 [Task] Adapt build script for entity store

Event Timeline

• bzimport raised the priority of this task from to Medium.Nov 22 2014, 1:55 AM

• bzimport added a project: MediaWiki-extensions-WikibaseRepository.

• bzimport set Reference to bz50911.

• bzimport added a subscriber: Unknown Object (MLST).

• bzimport created this task.Jul 7 2013, 10:57 PM

We are currently not planning to provide a SPARQL interface. Our query interface will be much less flexible, and much more geared for direct use in Wikipedia articles. Others are of course welcome to import our data and provide a SPARQL interface (still have to finish the RDF mapping though). I have hopes that perhaps the DBpedia and/or OpenLink folks will do that.

That being said: supporting transitive evaluation of (some) properties is indeed something we have tentatively planned, though the details are still hazy. I suggest to re-word this feature request to not ask about SPARQL in particular, but any way to query transitive relationships.

This bug has been marked as a duplicate of bug 59680 ***

@Lydia: How is 50911 a duplicate? Transitive queries may be necessary for, or tangentially related to, subproperties, but the two bugs are very different requests.

In terms of what the actual request is the work that needs to be done is very similar.

emw.wiki wrote:

Lydia, I agree with Steven Rawson. This issue does not seem like a duplicate of 59680.

All subproperties are transitive, but not all transitive properties are subproperties. This ticket seems to be a prerequisite for the ticket it was closed as a duplicate of. That is, I think issue 59680 should be marked as depending on this one.

This ticket was also created several months earlier. If there is an issue that should be resolved as a duplicate, I'd think it would be the one that describes the more narrow case and was filed after the original.

OrenBochman subscribed.Jan 2 2015, 11:01 AM

Izno awarded a token.Apr 9 2015, 4:40 PM

Izno subscribed.

Lydia_Pintscher closed subtask T54385: Query by one property and one value ("simple queries") (tracking) as Declined.Nov 9 2015, 11:26 AM

Restricted Application added a project: Wikidata. · View Herald TranscriptNov 9 2015, 11:26 AM