Help:Property constraints portal/Required qualifiers

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required qualifier constraint (Q21510856) specifies that some qualifier is required for this property. To limit the set of permitted qualifiers, use allowed qualifiers constraint.

For example, head of state (P35) statements should always have a start time (P580) qualifier.

If the property also has an allowed qualifiers constraint, all the required qualifiers must also be listed as permitted qualifiers there.

This constraint can only be checked on the main value of a statement; if any other constraint scope (P4680) is specified, an error is reported.

Possible actionsEdit

There are several possible ways to address a violation of this constraint:

  • The most likely case is that the missing qualifier should be added. If the value is not known, it might make sense to use unknown value Help.
  • It’s possible that the statement is a rare, but legitimate exception to the constraint, and nothing should be done.


This constraint has one mandatory parameter:

property (P2306)
Contains the required qualifier. Must contain exactly one property (no value Help or unknown value Help are not allowed). To add multiple required qualifiers, add multiple constraints of this type.


Example 1Edit

Example setting for population (P1082).

property constraint
  required qualifier constraint
property point in time
0 references
add reference

add value

Example 2Edit

Example setting for solubility (P2177).

property constraint
  required qualifier constraint
property solvent
0 references
add reference
  required qualifier constraint
property temperature
0 references
add reference

add value


When the constraint is set to the property, the following template is automatically displayed in the property talk page. The template is created by Module:Constraints using Template:Constraint, invoked from Template:Property documentation. Translations are defined at Module:i18n/constraints.

Required qualifier “determination method (P459): this property should be used with the listed qualifier. (Help)
Exceptions are possible as rare values may exist.
List of this constraint violations: Database reports/Constraint violations/P1082#mandatory qualifier, SPARQL, SPARQL (new)


Lists of properties which are set item required qualifier constraint.