Special property "Has uniqueness constraint"
From semantic-mediawiki.org
| Has uniqueness constraint | |
|---|---|
Allows to restrict value annotation to be unique
| |
| Further Information | |
| Provided by: | extension "Semantic MediaWiki "Allows to store and query data annotated to pages |
| Added: | 2.4.0 |
| Removed: | still in use |
| Alias: | has no alias |
| Optional: | yes |
| Visible: | yes |
| Annotable: | yes |
| Declarative: | yes |
| Key: | _PVUC
|
| Setting: | SMW_DV_PVUC
|
| Focus: | property restriction |
| In this wiki: | Property:Has uniqueness constraint |
| Table of Contents | |
Contents | |
The "Has uniqueness constraint" property is a special property in Semantic MediaWiki which got introduced with Semantic MediaWiki 2.4.0Released on 9 July 2016 and compatible with MW 1.19.0 - 1.27.x.1 and indicates that value assignments (annotations) to a property are expected to be unique. i.e. a specific data value for the respective property can only be added to one page. Semantic MediaWiki 2.5.0Released on 14 March 2017 and compatible with MW 1.23.0 - 1.29.x.2 made this feature more strict to only allow a data value for the respective property be added once.
Features and limitations[edit]
- Feature is not enabled by default (See the help page on configuration parameter
$smwgDVFeaturesSets the available features regarding property data values for details on configuring Semantic MediaWiki for special data value features including "Has uniqueness constraint" with theSMW_DV_PVUCconstant.) owl:FunctionalProperty34 is added to the RDF export that extends the property specification with theHas uniqueness constraintattribute
Usage[edit]
Add the following code to the property page:
[[Has uniqueness constraint::true]]
Examples[edit]
References
- ^ Semantic MediaWiki: GitHub pull request gh:smw:1463
- ^ Semantic MediaWiki: GitHub pull request gh:smw:2113
- ^ Semantic MediaWiki: GitHub pull request gh:smw:2167
- ^ "A functional property is a property that can have only one (unique) value y for each instance x, i.e. there cannot be two distinct values y1 and y2..." described by https://www.w3.org/TR/2004/REC-owl-ref-20040210/#FunctionalProperty-def
