Add the Book Class

Instruction

1. In the Class Browser, select the Object class.
2. Select the Classes | Add... command. The Define Class dialog is displayed.
3. Enter Book as the name.
4. Select library as the map file.
5. Click the OK button. The Class Browser displays the new Book class.
   
   

Real vs Abstract

A real class, unlike an abstract class, can be instantiated (objects of the class can be created). Abstract classes define common properties and methods that are inherited by real subclasses.

Persistent vs Transient

Persistent objects, unlike transient objects, are stored in the database. Transient objects are stored in memory until deleted.