Special property "Has uniqueness constraint"

Editing Properties and typesSpecial properties

Has uniqueness constraint
Allows to restrict value annotation to be unique
Further Information
Provided by:	extension "Semantic MediaWiki "No description was provided.
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

Template:Interlanguagelink: en The "Has uniqueness constraint" property is a special property in Semantic MediaWiki which got introduced with Semantic MediaWiki 2.4.0Released on an unknown date unknown versions of MediaWiki1 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 an unknown date unknown versions of MediaWiki2 made this feature more strict to only allow a data value for the respective property be added once.

Features and limitations

• 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 the SMW_DV_PVUC constant.)
• owl:FunctionalProperty34 is added to the RDF export that extends the property specification with the Has uniqueness constraint attribute

File:Smw-uniqueness-constraint-violation.png

Usage

Add the following code to the property page:

[[Has uniqueness constraint::true]]

Examples

• Page "Q1339" on <sandbox.semantic-mediawiki.org>
• Property page "NDL ID" on <sandbox.semantic-mediawiki.org>
• Pull request example "2113" on <sandbox.semantic-mediawiki.org>

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