This means since this implementation is not a pure object-oriented database, nor is it just a relational database. It now represents a hybrid of the two, so it is being call an object-relational database. An object-oriented database is one that can store data, the relationship of the data, and the way it interacts with other data. Since an object database understands the object customer and all its relationships, it can easily deal with the object customer and all that is needed to work with it. The object-relational model allows users to define object types, specifying both the structure of the data and the methods of operating on the data, and to use these data types within the relational model.
Objects are software representations of real-world entities.
Attributes model the structure of the real world entity. Methods implement specific operations that an application can perform on the data. Every object type has a constructor method that makes a new object according to the data type's specification. When objects are similar to one another in behaviors and other attributes, the can be put together into a class. This concept of classes, parent classes, subclasses, and superclasses allow for a level of abstraction for grouping objects.