N-ary Relation

A relation that connects more than two members. As with binary relations, the ends are Property elements listed in order in properties. In UML an n-ary relation is drawn as a diamond joined by a plain line to each participating class.

Property	Type	Description
type	"NaryRelation"	Discriminator.

NaryRelation carries the properties of Classifier (isAbstract, properties), Decoratable (stereotype, isDerived), and the properties common to all model elements.

The example below is a ternary allocation relation joining Employee, Project, and Role, with the cardinality of each end shown on its line to the diamond.

{
  "type": "NaryRelation",
  "id": "relation_2",
  "name": { "en": "allocation" },
  "stereotype": null,
  "isDerived": false,
  "isAbstract": false,
  "properties": ["end_employee", "end_project", "end_role"],
  "customProperties": null,
  "created": "2024-09-04",
  "modified": null,
  "alternativeNames": [],
  "description": null,
  "editorialNotes": [],
  "creators": [],
  "contributors": []
}

Its three ends are Property objects too, again referenced by id and defined separately. Their cardinalities match the diagram (1..* for end_employee, 1 for the others):

{
  "type": "Property",
  "id": "end_employee",
  "name": null,
  "stereotype": null,
  "isDerived": false,
  "propertyType": "class_employee",
  "cardinality": "1..*",
  "aggregationKind": null,
  "isOrdered": false,
  "isReadOnly": false,
  "subsettedProperties": [],
  "redefinedProperties": [],
  "customProperties": null,
  "created": "2024-09-04",
  "modified": null,
  "alternativeNames": [],
  "description": null,
  "editorialNotes": [],
  "creators": [],
  "contributors": []
}

{
  "type": "Property",
  "id": "end_project",
  "name": null,
  "stereotype": null,
  "isDerived": false,
  "propertyType": "class_project",
  "cardinality": "1",
  "aggregationKind": null,
  "isOrdered": false,
  "isReadOnly": false,
  "subsettedProperties": [],
  "redefinedProperties": [],
  "customProperties": null,
  "created": "2024-09-04",
  "modified": null,
  "alternativeNames": [],
  "description": null,
  "editorialNotes": [],
  "creators": [],
  "contributors": []
}

{
  "type": "Property",
  "id": "end_role",
  "name": null,
  "stereotype": null,
  "isDerived": false,
  "propertyType": "class_role",
  "cardinality": "1",
  "aggregationKind": null,
  "isOrdered": false,
  "isReadOnly": false,
  "subsettedProperties": [],
  "redefinedProperties": [],
  "customProperties": null,
  "created": "2024-09-04",
  "modified": null,
  "alternativeNames": [],
  "description": null,
  "editorialNotes": [],
  "creators": [],
  "contributors": []
}