Help:P4390

Help page for mapping relation type (P4390) . This help page will be included in Property talk:P4390. Please be careful editing it not to break the included page.

When to use "mapping relation" qualifiers?

External identifiers express an "equivalence relationship" between the item and an entity in an external database. In the great majority of cases (most prominently, persons) this is self-evident and sufficient. However, some vocabularies - for example, thesauri from the field of social sciences - may comprise concepts where more specific relationships are needed, because the external concept is not an exact match for the Wikidata item. For such cases, it is possible to qualify the relation further by use of "mapping relation" qualifier.

The allowed values stem from Simple Knowledge Organization System (Q2288360) (SKOS) mapping relations, they are:

• exact match indicates that two concepts have equivalent meaning, and the link can be exploited across a wide range of applications and schemes. The link is meant to be transitive (A = B and B = C means A = C).
• close match indicates that two concepts are sufficiently similar that they can be used interchangeably in many applications. This link is not meant to be transitive.
• narrow match indicates that one concept is narrower than the other (for the representation of hierarchical links). The link is not meant to be transitive.
• broad match indicates that one concept is broader than the other (inverse of narrowMatch). The link is not meant to be transitive.
• related match indicates a non-hierarchical assoziative relationship between two concepts. The link is not meant to be transitive.

These relations are introduced to allow more complete and more precise mappings to and from external knowledge organization systems. They not intended for adding random relationships to external entities. If an exatly matching item exists, almost always no other relation to the external id is necessary. If no exactly matching item exists, the external identifier should link to the closest matching wikidata item, not to more distantly related items, e.g. "Germany" "narrow match" "id-of-Berlin" or "Barak Obama" "close match" "id-of-Michelle Obama" are not appropriate.

Definitions of external id properties may enforce or proscribe the use of the "mapping relation" qualifier, by setting up a mandatory qualifier or allowed qualifiers constraint. Before adding qualifiers for individual values of a well established external id property, it may be advisable to discuss their use on the talk page of the property.