public RelationshipClassToken Create( 
   RelationshipClassDescription relationshipClassDescription
)

public void CreateRelationshipWithRelationshipRules(SchemaBuilder schemaBuilder)
{
  // Creating a 'BuildingType' table with two fields - BuildingType and BuildingTypeDescription
  FieldDescription buildingType = FieldDescription.CreateIntegerField("BuildingType");
  FieldDescription buildingTypeeDescription = FieldDescription.CreateStringField("BuildingTypeDescription", 100);
  TableDescription buildingTypeDescription = new TableDescription("BuildingType", new List<FieldDescription>() { buildingType, buildingTypeeDescription });
  TableToken buildingtypeToken = schemaBuilder.Create(buildingTypeDescription);

  // Creating a 'Building' feature class with three fields - BuildingId, Address, and BuildingType
  FieldDescription buildingId = FieldDescription.CreateIntegerField("BuildingId");
  FieldDescription buildingAddress = FieldDescription.CreateStringField("Address", 100);
  FieldDescription usageSubType = FieldDescription.CreateIntegerField("UsageSubtype");
  FeatureClassDescription featureClassDescription = new FeatureClassDescription("Building", new List<FieldDescription> { buildingId, buildingAddress, buildingType, usageSubType }, new ShapeDescription(GeometryType.Polygon, SpatialReferences.WGS84));

  // Set subtype details (optional)
  featureClassDescription.SubtypeFieldDescription = new SubtypeFieldDescription(usageSubType.Name, new Dictionary<int, string> { { 1, "Marketing" }, { 2, "Utility" } });

  FeatureClassToken buildingToken = schemaBuilder.Create(featureClassDescription);

  // Creating a 1:M relationship between the 'Building' feature class and 'BuildingType' table
  RelationshipClassDescription relationshipClassDescription = new RelationshipClassDescription("BuildingToBuildingType", new FeatureClassDescription(buildingToken), new TableDescription(buildingtypeToken),
    RelationshipCardinality.OneToMany, buildingType.Name, buildingType.Name)
  {
    RelationshipType = RelationshipType.Composite
  };

  // Adding relationship rules for the 'Marketing' subtype
  relationshipClassDescription.RelationshipRuleDescriptions.Add(new RelationshipRuleDescription(1, null));

  schemaBuilder.Create(relationshipClassDescription);
  schemaBuilder.Build();
}