... simple database access, oryou are creating middle-tier components to handle databaseaccess, understanding how to connect to a database, retrieveinformation, and manipulate data are critical to ... MustOverridemodifier, that class must be marked asMustInherit.For example, here you have a base Transportationclass that has a method,Move,that is marked as MustOverride. This means that Transportationmust ... from a base Transportationclass, which could also be usedas the basis for a Planeclass, a Trainclass, a HotAirBalloonclass, and so on.Polymorphism with InheritancePolymorphism was possible...