Help talk:Property constraints portal/sandbox
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- Commons link constraint
- Values for this statement should be valid links to Wikimedia Commons. Examples: image (P18) (“File” namespace), Commons category (P373) (“Category” namespace).
- allowed qualifiers
- See allowed qualifiers constraint.
- allowed qualifiers constraint
- Statements for this property should not have any qualifiers other than the listed ones. Examples: continent (P30) with qualifiers start time (P580) and end time (P582), and Freebase ID (P646) with no qualifiers at all.
- allowed units
- See allowed units constraint.
- conflicts-with constraint
- Items with this property should not have certain other properties or statements. Examples: sex or gender (P21) conflicts with author (P50), which in turn conflicts with instance of (P31)human (Q5).
- contemporary constraint
- Items with this property and values for this property should coexist at some point in time. Examples: mother (P25), country of citizenship (P27).
- difference-within-range constraint
- aka. difference within range. The difference between values for this property and for another property should be within a certain range or interval. For example, the difference between date of birth (P569) and date of death (P570) should be between 0 and 150 years.
- distinct values
- See distinct-values constraint.
- distinct-values constraint
- aka. unique value and distinct value. No two items should share a value for this property; each item’s value should be unique across all statements for this property in all of Wikidata. Almost all identifier properties have this constraint, since an identifier (ISBN, freebase ID, …) should uniquely identify an entity. Other examples include flag (P163) and anthem (P85).
- format constraint
- Values for this property should have a certain format. Often used for identifiers (n digits long, starts with a certain letter, consists of digits, …).
- inverse constraint
- Statements using this property should always have an inverse statement. Examples: father (P22)/mother (P25) with child (P40).
- item-requires-statement constraint
- Items using this property should also have certain other statements. For example, items with killed by (P157) should have place of death (P20), date of death (P570) and manner of death (P1196)homicide (Q149086).
- multi-value constraint
- Items should have more than one statement with this property (or none). Rarely used, but examples include cast member (P161), has tense (P3103) and has grammatical mood (P3161).
- one-of constraint
- Values for this property should be one of a given set of items. Example: driving side (P1622) should be either left (Q13196750) or right (Q14565199).
- range constraint
- Values for this property should be within a certain range or interval. Examples: flattening (P1102) is always between 0 and 1, and UTC date of spacecraft launch (P619) should not be before .
- required qualifier constraint
- Statements for this property must have all of the listed qualifiers. Example: stock exchange (P414) with ticker symbol (P249) and start time (P580).
- single-value constraint
- Items should have no more than one statement with this property. Often used for identifiers, but also many other properties: for example, people generally only have a single place of birth (P19) and place of death (P20).
- subject type constraint
- Items with this property should have a certain type. Example: Items with date of birth (P569) should be instance of (P31) human (Q5) or animal (Q729).
- symmetric constraint
- Statements using this property should always exist in both directions. Examples: sibling (P3373), twinned administrative body (P190).
- units / allowed units
- Values for this statement should only use certain units (or none). Examples: term length of office (P2097) (unit: year (Q577)), population (P1082) (no units).
- used as qualifier
- See allowed qualifiers constraint.
- used as qualifier constraint
- This property should only be used for qualifiers, not statements or references. Examples: house number (P670) (qualifier of located on street (P669)).
- used as reference
- See used as reference constraint.
- used as reference constraint
- aka source. This property should only be used for references, not statements or qualifiers. Examples: stated in (P248), imported from Wikimedia project (P143).
- used for values only constraint
- This property should only be used for statements, not qualifiers or references. Examples: most properties.
- used for values-only
- See used for values only constraint.
- value requires claim
- See target required claim
- value-requires-statement constraint
- aka. target required statement. Values for this property should also have certain other statements. For example, screenwriter (P58) values should have sex or gender (P21) and occupation (P106)screenwriter (Q28389).
- value-type constraint
- Values for this property should have a certain type. Example: mother (P25) should be instance of (P31) human (Q5) or animal (Q729).