Wikidata:Topics/Wikidata/Property constraints

SELECT ?constraint ?constraintLabel ?dataType ?dataTypeLabel
WHERE 
{
  ?constraint wdt:P31/wdt:P279* wd:Q21502402.
  OPTIONAL {
     ?constraint wdt:P8956 ?dataType.
     ?dataType wdt:P31/wdt:P279* wd:Q19798645.
  }

  SERVICE wikibase:label { bd:serviceParam wikibase:language "[AUTO_LANGUAGE],en". }
} ORDER BY ?dataTypeLabel

Try it!