Object-Oriented Databases

Object-Oriented Databases
An Object-oriented (OO) database is a new and evolving method of organizing data. The OO approach began as a new method to create programs. The goal is to define objects that can be reused in many programs – thus saving time and reducing errors. As we know (figure below), an object has three major components: a name, a set of properties or attributes, and a set of methods or functions. The properties describe the object – just as attributes describe an entity in the relational database. The “Methods” (function) are the true innovation of the OO approach. Methods are short programs that define the actions that each object can take.
For example, the code to add a new customer would be stored with the Customer object. The innovation is that these methods are stored with the object definition.
For Example:- classes (Customer, Order, Item, Order Item)
Item
ItemID
Item Name
Price
Add Item
Delete Item
Order Item
OrderId
ItemID
……………
OrderItem
Drop OrderItem
Order
OrderID
CustomerID
…………….
New Order
Delete Order

Customer
CustomerID
Name
………….
Add Customer
Drop Customer
Change Address












Objects have properties – just as relational entities have attributes that hold data to describe the object. Objects have methods that are functions that are functions the objects can perform.

We have still various properties/features of object orients model:-
- Encapsulation
- Data Hiding
- Inheritance
- Object/Class
- Polymorphism……etc.
The object-oriented data model is based on the object-oriented programming language paradigm, which is new in wide use. Inheritance, object/class, encapsulation etc, with methods to provide an interface to objects, are among the key concepts of object-oriented programming that have found applications in data modeling.