Wikidata:Item classification
This page documents classification of items in Wikidata.
Einführung
Classification is the act of grouping real world objects into classes of object. An introduction to classification in Wikidata can be found on Help:Item classification.
This page give more inside and some details about classification in Wikidata and some statistics.
Classification in Wikidata
Item classification in Wikidata is done via non-domain specific properties:
| Wikidata:Property | W3C RDF Schema 1.1 | Wikidata Property Constraint | Wikidata:Database reports/Popular properties | Wikidata:Database reports/ |
|---|---|---|---|---|
| subclass of (P279) | rdfs:subClassOf | target item has to be a subclass of (P279) entity (Q35120) | listed | Constraint violations/P279 |
| instance of (P31) | rdf:type | target item has to be a subclass of (P279) entity (Q35120) | ranked number 1 | Constraint violations/P31 |
Each, via a property constraint, requires entity (Q35120) to be the root item for any item that uses one these properties.
Both properties and a third property, part of (P361), are listed at Help:Basic membership properties.
Domain-specific classification properties
Some domain-specific classification properties exist, several have been deleted in favor of the two mentioned above.
| Property | Subproperty of | Status | Kommentar |
|---|---|---|---|
| parent taxon (P171) | P279 | existing | several constraint violations are caused by items that use this property, or are in the subclass-tree of such items. |
| P132 (P132) | P31 | existing | all items are in the subclass-tree of administrative territorial entity (Q56061), i.e. they cause no constraint violations. |
| vessel class (P289) | P31 | existing | had been proposed for deletion |
| P133 (P133) | existing | had been proposed for deletion | |
| P202 (P202) | P31 | existing | |
| P60 (P60) | P31 | deprecated | type of astronomical object (P60) |
| P302 (P302) | P31 | deleted | mountain type (P302) |
| P288 (P288) | P31 | deleted | watercraft type (P288) |
| P173 (P173) | P31 | deleted | type of election (P173) |
| P168 (P168) | P31 | deleted | type of structure (P168) |
Wikidata queries
Wikidata queries can be used to find all items classified in that generic way.
Maybe in the future it will be possible to use Wikidata:Glossary#Query to display information related to the following queries:
| Name | Description | WDQ | Link |
|---|---|---|---|
| Instance | instance of something | claim[31] | autolist2 wdq.wmflabs.org/api |
| Rooted instance | instance of entity or of one of its subclasses | claim[31:(tree[35120][][279])] | autolist2 wdq.wmflabs.org/api |
| Unrooted instance | instance of something but not of entity or one of its subclasses | claim[31] and noclaim[31:(tree[35120][][279])] | autolist2 wdq.wmflabs.org/api |
| Class | subclass of something | claim[279] | autolist2 wdq.wmflabs.org/api |
| Rooted class | subclass of entity or one of its subclasses | claim[279:(tree[35120][][279])] | autolist2 wdq.wmflabs.org/api |
| Unrooted class | subclass of something but not of entity or one of its subclasses | claim[279] and noclaim[279:(tree[35120][][279])] | autolist2 wdq.wmflabs.org/api |
| Direct subclass of root | direct subclass of entity | claim[279:35120] | autolist2 wdq.wmflabs.org/api |
| Instance and class | subclass of something and instance of something | claim[31] and claim[279] | autolist2 wdq.wmflabs.org/api |
| Instance of unrooted class | instance of a subclass of something but not of entity or one of its subclasses | ? | |
| ? | "subclass of" and "instance of" with the same value | ? |
Database reports
- Wikidata:Database reports/Item classification
- Wikidata:Database reports/Constraint violations/P279
- As of 2014-07-10 692 unrooted subclasses are instance of Wikimedia category (Q4167836), i.e. they are Wikimedia specific items. WDQ: claim[279] and noclaim[279:(tree[35120][][279])] and claim[31:4167836] [1].
- Wikidata:Database reports/Constraint violations/P31
Unrooted subclasses
- As of 2014-07-09 there are 848,643 items that have a claim parent taxon (P171), i.e. they might be classes and are not rooted as subclasses. [2]. They could be easily rooted with WiDar to "biota" or by a bot to more specific subclasses. There might be reasons that this has not been done yet, the project for taxonomy is located at at Wikidata:WikiProject Taxonomy.
- Further unrooted subclasses are instances of taxon (Q16521).
Reduced WDQ not showing taxons nor Wikimedia category items:
- claim[279] and noclaim[279:(tree[35120][][279])] and noclaim[31:16521] and noclaim[171] and noclaim[31:4167836]
- autolist2
Templates
- Template:Item classification - shows a superclass tree based on subclass of (P279) and a link to the subclass tree
- Template:Item documentation includes Template:Item classification and provides extra links, e.g. to a lists of instances
- Template:Type (instance of)
- Template:SubType (subclass of)