Generalization classes

Creating an instance of a generalization relationship

Again, our prime concern is that all attributes, including referential attributes are initialized correctly. Since a subclass holds a reference to each of its superclasses, it follows that a subclass cannot be created without specifying its superclass instance. This can all be done in a single action, or be split apart with the superclasses being created first. In either case, it is important to ensure the integrity of all instances in a generalization, with no childless superclasses lying around.

*Off Duty ATC &R1 *Air Traffic Controller( ID:newid, Name:newname, Date of birth:dob )