Inconsistencies between Wikidata and Structured Data about Snak's "datatype" from wbgetentities API results
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	valerio.bozzolan
	Mar 3 2020, 6:48 PM

Description

Hello everybody!

I noticed that snaks in Wikimedia Commons' Structured Data may have not the "datatype" attribute.

Example in Wikidata that has the "datatype" attribute:

https://www.wikidata.org/w/api.php?action=wbgetentities&ids=Q1&props=claims

"mainsnak": {
    "snaktype": "value",
    "property": "P793",
    "hash": "46559e43804873b0d843230010c6e9942593b8af",
    "datavalue": {
        "value": {
            "entity-type": "item",
            "numeric-id": 323,
            "id": "Q323"
        },
        "type": "wikibase-entityid"
    },
    "datatype": "wikibase-item"
},

Then an example in Wikimedia Commons where the "datatype" is not provided:

https://commons.wikimedia.org/w/api.php?action=wbgetentities&ids=M70758296&props=claims

"mainsnak": {
    "snaktype": "value",
    "property": "P180",
    "hash": "6f6cd82613d00eb32e7c17e71d116637dbc2635a",
    "datavalue": {
        "value": {
            "entity-type": "item",
            "numeric-id": 55170514,
            "id": "Q55170514"
        },
        "type": "wikibase-entityid"
    }
}

I know that everything is in alpha, but I don't understand if this an undocumented inconsistency between these two Wikibase instances or if this is a transition for a removal of this attribute. Are there some public thoughts about this?

Thank you!

This is somehow related to other inconsistencies found, like this:

T149410: For consistency MediaInfo serialization should use "claims" as key, rather than "statements"

Related Objects

Mentioned In: T311977: Wikimedia Commons entity dumps are lacking datatype field
T301089: Can the JSON format of a wikidata item and that of a Structure Data Commons be alligned?
T271105: wbeditentity response does not contain lemma data
Mentioned Here: T271105: wbeditentity response does not contain lemma data
T149410: For consistency MediaInfo serialization should use "claims" as key, rather than "statements"

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valerio.bozzolan created this task.Mar 3 2020, 6:48 PM

Restricted Application added a project: Structured-Data-Backlog. · View Herald TranscriptMar 3 2020, 6:48 PM

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valerio.bozzolan renamed this task from Missing "datatype" from statements returned by wbgetentities in Structured Data to Inconsistence between Wikidata and Structured Data about Snak's "datatype" in wbgetentities.Mar 3 2020, 6:53 PM

valerio.bozzolan updated the task description. (Show Details)

valerio.bozzolan renamed this task from Inconsistence between Wikidata and Structured Data about Snak's "datatype" in wbgetentities to Inconsistencies between Wikidata and Structured Data about Snak's "datatype" from wbgetentities API results.Mar 3 2020, 7:00 PM

valerio.bozzolan updated the task description. (Show Details)

• Sarahmarie1981 edited projects, added WMDE-Tech-Communication-Source-Code-Berlin; removed Structured-Data-Backlog.Mar 16 2020, 3:30 PM

Aklapper removed a project: WMDE-Tech-Communication-Source-Code-Berlin.Mar 16 2020, 4:11 PM

JJMC89 added a project: Structured-Data-Backlog.Mar 17 2020, 6:50 PM

Yes, that "bug" or "feature" cause my c:Module:Wikidata date not to work with SDC entities. The fix was simple bit it took a long time to debug. It would be nice if SDC used the same schema, interface, etc. as Wikidata, so we do not have to be wasting time debugging two almost identical systems.

CBogen moved this task from Triage to SDoC Statements on the Structured-Data-Backlog board.Aug 25 2020, 8:22 PM

The "datatype" is missing because Wikibase only adds it to a certain hard-coded list of “paths” in the JSON, and (currently) all of those paths expect "claims", not "statements". (So, yes, this is due to T149410.)

This means that the "datatype" is present in the wbgetclaims response, since that uses the key "claims":

$ curl -s 'https://commons.wikimedia.org/w/api.php?action=wbgetentities&ids=M80857538&format=json&formatversion=2' | jq .entities.M80857538.statements.P180[0].mainsnak
{
  "snaktype": "value",
  "property": "P180",
  "hash": "a15d400991061ac3ac583f46991b86f59d7d00af",
  "datavalue": {
    "value": {
      "entity-type": "item",
      "numeric-id": 1426529,
      "id": "Q1426529"
    },
    "type": "wikibase-entityid"
  }
}
$ curl -s 'https://commons.wikimedia.org/w/api.php?action=wbgetclaims&entity=M80857538&format=json&formatversion=2' | jq .claims.P180[0].mainsnak
{
  "snaktype": "value",
  "property": "P180",
  "hash": "a15d400991061ac3ac583f46991b86f59d7d00af",
  "datavalue": {
    "value": {
      "entity-type": "item",
      "numeric-id": 1426529,
      "id": "Q1426529"
    },
    "type": "wikibase-entityid"
  },
  "datatype": "wikibase-item"
}