🛒 Python OOP Sales Management System

A structured and modular sales management system built in Python to demonstrate advanced Object-Oriented Programming principles.

This project models real-world sales entities such as products, users, and employees using clean OOP architecture.

---

🚀 Key Features

• Abstract Base Class (Person)
• Inheritance (User, Employee)
• Polymorphism (display_info method)
• Encapsulation (private & protected attributes)
• Inventory validation
• Shopping history tracking
• Salary management with percentage increase
• Randomized product assignment simulation

---

🧠 OOP Concepts Demonstrated

✅ Encapsulation

• Private attributes: __price, __salary
• Protected attributes: _email, _address, _description
• Controlled access via getters and setters

✅ Inheritance

• Employee and User inherit from abstract base class Person

✅ Polymorphism

• display_info() implemented differently in each subclass
• Unified interface used in main.py

✅ Abstract Classes

• Person implemented using Python's abc module

---

📂 Project Structure

oop-online-store-system/
├── models/
│   ├── employee.py
│   ├── person.py
│   ├── product.py
│   └── user.py
├── .gitignore
├── README.md
├── main.py
└── requirements.txt

---

▶️ How to Run

1. Clone the repository:

   git clone https://github.com/nicktm8/oop-online-store-system.git

2. Navigate to the project directory:

   cd oop-online-store-system

3. Run the program:

   python main.py

---

📊 Example Functionality

• Displays product inventory
• Updates product prices (+10% simulation)
• Demonstrates encapsulation via getters and setters
• Shows polymorphic display of users and employees
• Calculates total spending per user
• Increases employee salaries

---

🎯 Project Purpose

This project was developed to strengthen understanding of:

• Clean OOP architecture
• Writing modular Python code
• Structuring multi-file projects
• Applying theoretical OOP concepts in practice

It serves as a foundational backend-style system suitable for further expansion (CLI interface, database integration, REST API version, etc.).

---

🔮 Possible Future Improvements

• CLI interactive menu
• Data persistence (JSON or SQLite)
• Logging system
• Unit testing (pytest)
• Flask or FastAPI API version

---

👨‍💻 Author

Nick Tem
Aspiring Python Developer

GitHub: https://github.com/nicktm8