In most PC-based software, the F1 key has a special meaning. Pressing F1 will invoke a context-sensitive help function. A rush order would include overnight mail calculations, and the COD order would contain additional computations for the total amount due. This is equivalent to the procedural language code shown in Figure 3 . Encapsulation Encapsulation means that each object within the system has a well-defined interface with distinct borders.
Encapsulation closely parallels the concept of information hiding.
Encapsulation also ensures that all updates to a database are performed by way of the behaviors associated with the database objects. From a programming perspective, an object is an encapsulated routine of data and behaviors. Once created, an object is treated as a variable of its own type. For example, an object of class CAR is created as a routine with a data type called CAR, and it is treated as a compound variable by the program. Extensibility Extensibility is the ability of the Oracle8 engine to add new behaviors to an existing application without affecting the existing application shell.