Library Management System

A comprehensive command-line library management system built in Python that allows librarians to manage books, DVDs, magazines, and users with full borrowing/returning functionality.

🚀 Features

• Item Management: Add, remove, update, and view books, DVDs, and magazines
• User Management: Register and manage library users
• Borrowing System: Track item borrowing and returns
• Reservation System: Reserve items (books and DVDs)
• Data Persistence: Automatic JSON file storage
• Input Validation: Comprehensive error handling and data validation
• Interactive CLI: User-friendly menu-driven interface

📋 Requirements

• Python 3.7+
• No external dependencies (uses only Python standard library)

🏗️ Architecture

System Flow Chart

For a visual representation of the system architecture and data flow, view our System Flow Chart on Miro.

Core Classes

• Library: Main controller class managing items and users
• LibraryItem: Abstract base class for all library items
• Book: Represents books with genre information
• DVD: Represents DVDs with duration information
• Magazine: Represents magazines with genre information
• User: Represents library users with borrowing history
• Reservable: Interface for items that can be reserved

Data Structure

Item ID Format

• Books: B-Aa-YYYY-N (e.g., B-JD-2020-1)
• DVDs: D-Aa-YYYY-N (e.g., D-SS-2019-2)
• Magazines: M-Aa-YYYY-N (e.g., M-NG-2021-3)

Where:

• T: Item type (B/D/M)
• Aa: Author initials (first letter of first and last word)
• YYYY: Publication year
• N: Sequential item number

User ID Format

• Users: U-Ff-Ll-N (e.g., U-Jo-Sm-1)

Where:

• U: User identifier
• Ff: First name initials (first two characters)
• Ll: Last name initials (first two characters)
• N: Sequential user number

🚀 Quick Start

Running the Application

# Navigate to the project directory
cd "Library Management System"

# Run the main application
python main.py

Basic Usage

1. Start the application: The main menu will appear
2. Navigate menus: Use number keys to select options
3. Add items: Go to "Items" → "Add Item" to add books/DVDs/magazines
4. Add users: Go to "Users" → "Add User" to register new users
5. Borrow items: Go to "Borrow/Return" → "Borrow Item"
6. Return items: Go to "Borrow/Return" → "Return Item"
7. Save and exit: Choose "Exit" from main menu

📁 Project Structure

Library Management System/
├── data/                           # Data storage
│   ├── items.json                 # Library items data
│   └── users.json                 # User data
├── modules/                       # Source code
│   ├── main.py                   # Main application and CLI
│   ├── library.py                # Core library management
│   ├── library_item.py           # Abstract base class
│   ├── book.py                   # Book implementation
│   ├── dvd.py                    # DVD implementation
│   ├── magazine.py               # Magazine implementation
│   ├── user.py                   # User management
│   ├── reservable.py             # Reservation interface
│   └── exceptions.py             # Custom exceptions
├── methods_exceptions/           # Documentation
│   └── *.txt                     # Method documentation files
└── README.md                     # This file

🔧 API Documentation

Library Class

The main controller class that manages all library operations.

Key Methods

• add_item(item): Add a new item to the library
• remove_item(item): Remove an item from the library
• update_item(item, new_item): Update item attributes
• add_user(user): Register a new user
• remove_user(user): Remove a user from the system
• borrow_item(user, item): Borrow an item for a user
• return_item(user, item): Return a borrowed item
• load_data(): Load data from JSON files
• save_data(): Save data to JSON files

Item Classes

Book

book = Book(title, author, year, available, genre, custom_id=None)

DVD

dvd = DVD(title, author, year, available, duration, custom_id=None)

Magazine

magazine = Magazine(title, author, year, available, genre, custom_id=None)

User Class

user = User(first_name, last_name, custom_id=None)

🛡️ Error Handling

The system includes comprehensive error handling with custom exceptions:

• InvalidDataTypeError: Wrong data type provided
• InvalidValueError: Invalid value (empty, too short, etc.)
• MissingFieldError: Required field missing from data
• ItemNotFoundError: Item doesn't exist in library
• UserNotFoundError: User doesn't exist in system
• ItemNotAvailableError: Item is not available for borrowing
• ItemNotBorrowedError: User hasn't borrowed the item
• ItemAlreadyExistsError: Item already exists in library
• UserAlreadyExistsError: User already exists in system

💾 Data Storage

Items JSON Structure

{
  "id": "B-JD-2020-1",
  "type": "Book",
  "title": "The Great Gatsby",
  "author": "F. Scott Fitzgerald",
  "year": 1925,
  "available": true,
  "genre": "Fiction"
}

Users JSON Structure

{
  "id": "U-Jo-Sm-1",
  "first_name": "John",
  "last_name": "Smith",
  "borrowed_items": ["B-JD-2020-1", "D-SS-2019-2"]
}

🧪 Development

Adding New Item Types

1. Create a new class inheriting from LibraryItem
2. Implement required abstract methods
3. Add validation logic
4. Update the Library.__create_item() method
5. Add to the main menu system

Testing

The system includes comprehensive input validation and error handling. Test edge cases by:

• Providing invalid data types
• Using empty or invalid strings
• Testing boundary conditions
• Verifying data persistence

📝 License

This project is open source and available under the MIT License.

🤝 Contributing

1. Fork the repository
2. Create a feature branch
3. Make your changes
4. Add appropriate documentation
5. Submit a pull request

📞 Support

For issues or questions, please open an issue in the repository or contact the development team (only me).