Object - Oriented Concepts:

The most important concepts of the object-oriented methodology are discussed as follows:

Classes:

CLASS refers to the definition of an object. In simple terms, it is the blue print for an object.

It is a standard representation consisting of data members and their functions. The Functions and variables that are part of the class declaration of a class definition are considered to be public members of that class.

Abstract datatypes model classes of data within the database. These datatypes can share the similar structure. For instance, if you want to move a car, you can either move the car (an object) or you can break it into its elements (tires, steering column etc.), move the components individually and then perform a join in the new location.  As an object treating the car is a more natural way of relating to it and simplifies your interaction with it.

Methods & Messages:

The method is the incorporation of a specific behavior assigned to an object. It is a function of a particular class.  That implement the operations to be performed on a real world object and the output of the method is message. Therefore a message is essentially an executed function belonging to a class member.  The method is the means through that objects communicate with one another.