Special properties

Special properties
Provides an overview about properties that are build into Semantic MediaWiki.
Table of Contents

This page describes the 66 special properties that are built-in to Semantic MediaWiki (SMW). They are needed to make the system work. They appear in a page's factbox, on special page "Properties"Lists properties and displays their usage and on special page "Browse"Shows all properties and their values annotated to a page in italic. Since Semantic MediaWiki 1.4.0Released on 21 November 2008 and compatible with MW 1.13.x - 1.16.x., special properties can be used in browsing interfaces and inline queries just like all other properties. Also see the help page properties and types for more information.

Special properties may also be provided by extensions to Semantic MediaWiki like, e.g. extension "Semantic Extra Special Properties"Adds some extra special properties to all pages or extension "Semantic Cite"Allows to manage citation resources using semantic annotations, etc. These however are currently not being documented here.

The names and aliases of special properties are reserved and cannot be used for other properties. Additionally special properties should only be used according to their documented purpose! It is not necessary to create pages for special properties. They will perform their special behavior even if your wiki does not have a property page for it.

Overview

The following table gives an overview of all 66 special properties provided by Semantic MediaWiki:

Name	Description	Help	Added	Key
Allows value	Lists one permissible value for a property	help page	1.0	_PVAL
Corresponds to	Gives the conversion factor for some unit of a physical quantity and the possible names for that unit	help page	1.0	_CONV
Display units	Specifies a comma-separated list of units or formats that a property should use in display	help page	1.0	_UNIT
Equivalent URI	Marks a page in the wiki as having a well-known meaning beyond this wiki, in an external URI	help page	1.0	_URI
Has type	Assigns a datatype to a property	help page	1.0	_TYPE
Imported from	Allows users to reuse elements of external vocabularies directly within the wiki	help page	1.0	_IMPO
Provides service	Adds service links to properties	help page	1.0	_SERV
Subproperty of	Lets you indicate that one property is a subproperty of another	help page	1.0	_SUBP
Modification date	Holds a fixed value that corresponds to the date of the last modification of each page	help page	1.4.0	_MDAT
Has improper value for	Alerts in case the assigned value to a property is invalid	help page	1.4.2	_ERRP
Has fields	Defines a short list of fields with a fixed type and order for datatype Record	help page	1.5.0	_LIST
Subcategory of	Lets you explicitly indicate that one category is a subcategory of another	help page	1.5.0	_SUBC
Creation date	Holds a fixed value that corresponds to the date of the first revision of each page	help page	1.7.0	_CDAT
Has subobject	Holds the subobjects set on a page	help page	1.7.0	_SOBJ
Is a new page	Holds a value marking a page as being new or not	help page	1.7.1	_NEWP
Last editor is	Holds the page name of the user who created the last page revision	help page	1.7.1	_LEDT
Has query	Links a page to the subobject created by a query recording its profile	help page	1.8.0	_ASK
Query depth	Holds the value of the property depth of a query	help page	1.8.0	_ASKDE
Query format	Holds the name of the result format used in a query	help page	1.8.0	_ASKFO
Query size	Holds the value of the number of conditions in a query	help page	1.8.0	_ASKSI
Query string	Holds the conditions of the query as a string	help page	1.8.0	_ASKST
Query duration	Holds the value of the duration a query took to execute	help page	1.9.0	_ASKDU
MIME type	Holds the MIME type of an uploaded file	help page	1.9.1	_MIME
Media type	Holds the Media type of an uploaded file	help page	1.9.1	_MEDIA
Allows pattern	Pattern to match a permissible value	help page	2.4.0	_PVAP
Display precision of	Allows to define the display precision in digits	help page	2.4.0	_PREC
Display title of	Holds a specific denote title for an entity	help page	2.4.0	_DTITLE
Has property description	Adds localizable context help to properties	help page	2.4.0	_PDESC
Has uniqueness constraint	Allows to restrict value annotation to be unique	help page	2.4.0	_PVUC
Language code	Handles BCP47 conform language codes specifying the language of the annotated text	help page	2.4.0	_LCODE
Processing error	Holds a "container" with further information about a problem and allows to explore and rectify it	help page	2.4.0	_ERRC
Processing error message	Holds a textual description of an error which occurred during the processing of a page	help page	2.4.0	_ERRT
Allows value list	Adds a reference to a list of permissible values for a property	help page	2.5.0	_PVALI
External formatter URI	Declares an external URL with placeholders $1, $2	help page	2.5.0	_PEFU
External identifier	Specifies an external identifier	help page	2.5.0	_PEID
Has preferred property label	Adds localizable labels to a property	help page	2.5.0	_PPLB
Is edit protected	Stores the status of an edit restriction of a page	help page	2.5.0	_EDIP
Query parameters	Holds the parameters a query used to select its output	help page	2.5.0	_ASKPA
Query source	Holds the identifier of an alternative (e.g. remote) query source	help page	2.5.0	_ASKSC
Change propagation	Holds the new property specification of a property or category page	help page	3.0.0	_CHGPRO
Is property group	Marks a category for holding properties belonging to a property group	help page	3.0.0	_PPGR
Query state	Holds the status code a query uses to define its internal state	help page	3.0.0	_ASKCO
Schema definition	Holds the definition of a schema what was added to namespace "smw/schema"	help page	3.0.0	_SCHEMA_DEF
Schema description	Holds the description of a schema what was added to namespace "smw/schema"	help page	3.0.0	_SCHEMA_DESC
Schema link	Holds the link of a schema what was added to namespace "smw/schema"	help page	3.0.0	_SCHEMA_LINK
Schema tag	Holds the tags to a schema what was added to namespace "smw/schema"	help page	3.0.0	_SCHEMA_TAG
Schema type	Holds the type of a schema what was added to namespace "smw/schema"	help page	3.0.0	_SCHEMA_TYPE
Attachment link	Holds the links to files embedded on a page	help page	3.1.0	_ATTCH_LINK
Constraint schema	Holds the name of a constraint schema which is not restricted to single constraint types	help page	3.1.0	_CONSTRAINT_SCHEMA
Processing error type	Holds the type of an error which occurred during the processing of a page	help page	3.1.0	_ERR_TYPE
Profile schema	Holds the name of a profile schema which declares characteristics for annotations	help page	3.1.0	_PROFILE_SCHEMA

See also

• Help page on property keys

Note

Special properties can also be classified according to a certain behaviour they have or allow for. See the following help pages for further information:

• Special properties (annotable)
• Special properties (declarative)
• Special properties (optional)
• Special properties (visible)

Applying styles

In case you would like to make special properties easier to be identified in the factbox, on special page "Properties"Lists properties and displays their usage and on special page "Browse"Shows all properties and their values annotated to a page just add, e.g. the following CSS code to the MediaWiki:Common.css page.

.smwbuiltin a,
.smwbuiltin a.new {
    color: #ff8000;
}

Special properties are are already printed in italics prior to the extra formatting mentioned here.

"Has description</br>" contains a listed "LF" character as part of the property label and has therefore been classified as invalid. "Has description</br>" contains a listed "LF" character as part of the property label and has therefore been classified as invalid. "Has description</br>" contains a listed "LF" character as part of the property label and has therefore been classified as invalid. "Has description</br>" contains a listed "LF" character as part of the property label and has therefore been classified as invalid. "Has description</br>" contains a listed "LF" character as part of the property label and has therefore been classified as invalid.