Key Concepts:

1. Objects:
   • Definition: Objects act as encapsulated entities that perform specific actions and can store various types of data, such as videos and pictures.
   • Behavior: Objects function as black boxes that can be substituted if they support the required operations.
2. Encapsulation (Data Hiding):
   • Purpose: Protects the internal state of an object from unintended or accidental modifications by restricting access to its data.
3. Messages:
   • Definition: Instructions sent to an object to trigger specific actions or behaviors.
4. Methods:
   • Definition: The code within an object that defines how it responds to messages. Methods encapsulate behavior and functionality.
5. Behavior:
   • Definition: The observable actions or responses of an object when it receives a message.
6. Class:
   • Definition: A blueprint that defines the structure and behavior of objects. It includes methods and attributes shared by objects created from the class.
7. Instance:
   • Definition: A specific realization of a class. Each object created from a class is an instance of that class.
8. Inheritance:
   • Definition: Mechanism allowing a subclass to inherit attributes and methods from a superclass, promoting code reusability and hierarchical relationships.
9. Multiple Inheritance:
   • Definition: A subclass inherits characteristics and behaviors from more than one parent class.
10. Delegation:
    • Definition: The process of forwarding a request or action to another object, enabling code reuse and separation of concerns.
11. Polymorphism:
    • Definition: The ability of objects from different classes to respond to the same message (method call) in different ways. It allows for a single interface to interact with different underlying forms.
12. Poly-instantiation:
    • Definition: The presence of multiple rows in a relational database table that appear to have the same primary key but contain different data for different classification levels. It is often used to prevent inference attacks.

Phases of Object-Oriented Development:

1. Object-Oriented Requirements Analysis (OORA):
   • Focus: Identifies and defines classes of objects and their interactions based on the system requirements.
2. Object-Oriented Analysis (OOA):
   • Focus: Models and understands the problem domain, including the identification of common classes and objects within a specific problem area.
3. Domain Analysis (DA):
   • Focus: Identifies common classes and objects across different applications within a specific domain to facilitate reuse and consistency.
4. Object-Oriented Design (OOD):
   • Focus: Defines the system’s design using objects and classes, specifying how objects will interact and how their behaviors will be implemented.
5. Object-Oriented Programming (OOP):
   • Focus: Implements the design by coding objects and methods in a programming language that supports object-oriented principles.

Object Request Brokers (ORBs):

1. Definition:
   • Middleware that manages object interactions across networks, handling requests and distributing them to appropriate objects.
2. Standards:
   • CORBA (Common Object Request Broker Architecture): Allows interoperability between programs written in different languages and running on different platforms through Interface Definition Language (IDL).
   • COM (Component Object Model): A Microsoft standard for component-based software development.

Understanding these concepts and phases helps in effectively applying object-oriented principles to software development, enhancing modularity, reusability, and maintainability.