# required qualifier constraint

> type of constraint for Wikidata properties: used to specify that the listed qualifier has to be used

**Wikidata**: [Q21510856](https://www.wikidata.org/wiki/Q21510856)  
**Source**: https://4ort.xyz/entity/required-qualifier-constraint


## References

1. [Source](https://raw.githubusercontent.com/Pascalco/harvesttemplates/master/getconstraints.php)
2. [Source](https://raw.githubusercontent.com/OpenRefine/OpenRefine/master/extensions/wikidata/src/org/openrefine/wikidata/qa/WikidataConstraintFetcher.java)
3. [Source](https://raw.githubusercontent.com/wikimedia/mediawiki-extensions-WikibaseQualityConstraints/dd6d6f25d094b1f0fe2cae7a47dac2f02e842c30/extension.json)