The UserData object contains user-defined XY data. The UserData object has no constructor; it is created automatically when an Odb object is created.
odb.userData()
The UserData object can have the following member:
odb_UserXYDataRepository& xyDataObjects();
odb_UserXYData& xyDataObjects(const odb_String& xyName);
A repository of UserXYData objects.