384 Chapter 18: The Object-Relational Data Model simple data types and using those classes to build more com- plex classes, and so on. Benefits of Object- Orientation There are several reasons why the object-oriented paradigm has become so pervasive in programming. Among the perceived benefits are the following: An object-oriented program consists of modular units that are independent of one another. These units can therefore be reused in multiple programs, saving devel- opment time. For example, if you have a well-debugged employee class, you can use it in any of your business programs that require data about employees. As long as a class's public interface remains unchanged, the internals of the class can be modified as needed without requiring any changes to the programs that use the class. This can significantly speed up program modi- fication. It can also make program modification more