Some properties are supposed to only hold unique values in statements. This can be modeled via a unique value constraint. There are a lot of these values that only have to be unique with a given qualifier. As an editor I want to be able to define which qualifiers are acceptable to keep the uniqueness of values for a given property so I can model reality more completely without causing constraint violations.
Existing modeling example: https://www.wikidata.org/wiki/Property:P856
Examples where this is likely to be used:
- heads of government over time
- official websites by country
Questions that came up:
- What happens if one value has a qualifier for the separating property and one doesn’t? -> It is not considered a violation.
- Are two unknown values for the separating property considered different? -> Yes.
- What happens if values have multiple qualifiers for the separating properties? -> We are lenient and accept the values as long as the sets of qualifiers are different, even if they partially overlap.