Often when you add to a association with a link class, you want do things with the created link object.
Do like this;
Add a method to either of the "main" classes with a content similar to this;
self.Flights.add(aFlight); self.Bookings->select(b | b.Flight = aFlight)->first
It adds the object at the other end to the association, and then looks up the created link object. In this case, a Booking object and returns it.
Please note that it's usually very good to set the names on the links, both the InnerLinkName and the LinkRoleName.
In this example, this is the InnerLinkName and the LinkRoleName for the Persons end of the association.
Note! From the Booking object, it's only one Person object in the association. Hence, Person, not Persons
See also: Association classes