Corresponding C++ library: TG_Db 

Optional hint to provide indexing information to optimize relationship querying.

Schema: Bentley_Standard_CustomAttributes, Version: 1.13, Class: ECDbRelationshipClassHint Available properties: "PreferredDirection"(string), "AllowDuplicateRelationships"(bool), "SourceECIdColumn"(string), "SourceECClassIdColumn"(string), "TargetECClassIdColumn"(string), "TargetECIdColumn"(string)