createRelation abstract method

Future<WriteResult> createRelation(
  1. String resourceKey,
  2. Object id,
  3. RelationDescriptor relation,
  4. Map<String, dynamic> values,
)

POST /{resource}/{id}/relations/{relation} — creates one child row through the relationship (P9). Same never-throw contract as create; a 422 carries errors keyed by the CHILD resource's field names.

Implementation

Future<WriteResult> createRelation(
  String resourceKey,
  Object id,
  RelationDescriptor relation,
  Map<String, dynamic> values,
);