Table 1. Constraint types for the usage of Wikidata properties.
Each property constraint is given with its Wikidata identifier, an English label and an English description.
| Wikidata ID | Constraint type | Description |
|---|---|---|
| Q19474404 | Single value constraint | Constraint used to specify that this property generally contains a single value per item |
| Q21502404 | Format constraint | Constraint used to specify that the value for this property has to correspond to a given pattern |
| Q21502408 | Mandatory constraint | Status of a Wikidata property constraint: indicates that the specified constraint applies to the subject property without exception and must not be violated |
| Q21502410 | Distinct values constraint | Constraint used to specify that the value for this property is likely to be different from all other items |
| Q21510852 | Commons link constraint | Constraint used to specify that the value must link to an existing Wikimedia Commons page |
| Q21510854 | Difference within range constraint | Constraint used to specify that the value of a given statement should only differ in the given way. Use with qualifiers minimum quantity/maximum quantity |
| Q21510856 | Mandatory qualifier constraint | Constraint used to specify that the listed qualifier has to be used |
| Q21510862 | Symmetric constraint | Constraint used to specify that the referenced entity should also link back to this entity |
| Q21510863 | Used as qualifier constraint | Constraint used to specify that a property must only be used as a qualifier |
| Q21510864 | Value requires statement constraint | Constraint used to specify that the referenced item should have a statement with a given property |
| Q21510495 | Relation of type constraint | Relation establishing dependency between types/meta-levels of its members |
| Q21510851 | Allowed qualifiers constraint | Constraint used to specify that only the listed qualifiers should be used. Novalue disallows any qualifier |
| Q21510865 | Value type constraint | Constraint used to specify that the referenced item should be a subclass or instance of a given type |
| Q21514353 | Allowed units constraint | Constraint used to specify that only listed units may be used |
| Q21510857 | Multi-value constraint | Constraint used to specify that a property generally contains more than one value per item |
| Q21510859 | One-of constraint | Constraint used to specify that the value for this property has to be one of a given set of items |
| Q21510860 | Range constraint | Constraint used to specify that the value must be between two given values |
| Q21528958 | Used for values only constraint | Constraint used to specify that a property can only be used as a property for values, not as a qualifier or reference |
| Q21528959 | Used as reference constraint | Constraint used to specify that a property must only be used in references or instances of citation (Q1713) |
| Q25796498 | Contemporary constraint | Constraint used to specify that the subject and the object have to coincide or coexist at some point in history |
| Q21502838 | Conflicts-with constraint | Constraint used to specify that an item must not have a given statement |
| Q21503247 | Item requires statement constraint | Constraint used to specify that an item with this statement should also have another given property |
| Q21503250 | Type constraint | Constraint used to specify that the item described by such properties should be a subclass or instance of a given type |
| Q54554025 | Citation needed constraint | Constraint specifies that a property must have at least one reference |
| Q62026391 | Suggestion constraint | Status of a Wikidata property constraint: indicates that the specified constraint merely suggests additional improvements, and violations are not as severe as for regular or mandatory constraints |
| Q64006792 | Lexeme value requires lexical category constraint | Constraint used to specify that the referenced lexeme should have a given lexical category |
| Q42750658 | Value constraint | Class of constraints on the value of a statement with a given property. For constraint: use specific items (e.g., “value type constraint”, “value requires statement constraint”, “format constraint”, etc.) |
| Q51723761 | No bounds constraint | Constraint specifies that a property must only have values that do not have bounds |
| Q52004125 | Allowed entity types constraint | Constraint used to specify that only listed entity types are valid for this property |
| Q52060874 | Single best value constraint | Constraint used to specify that this property generally contains a single “best” value per item, though other values may be included as long as the “best” value is marked with a preferred rank |
| Q52558054 | None of constraint | Constraint specifying values that should not be used for the given property |
| Q52712340 | One-of qualifier value property constraint | Constraint used to specify which values can be used for a given qualifier when used on a specific property |
| Q52848401 | Integer constraint | Constraint used when values have to be integer only |
| Q53869507 | Property scope constraint | Constraint to define the scope of the property (main value, qualifier, references, or combination); only supported by KrBot currently |