A Comprehensive Tutorial on Python: Building an Advanced Banking System from Scratch

Have you ever wondered how a banking system operates under the hood? Or perhaps you’re eager to build a sophisticated banking system from scratch using Python to sharpen your programming skills? In this advanced tutorial, we’ll guide you step-by-step through the process of creating a robust banking system. We’ll dive into essential programming concepts, such as object-oriented programming (OOP), file handling, and advanced data manipulation, setting a solid foundation for even more complex projects.

Prerequisites

Before embarking on this journey, ensure you have:

• Solid Python Knowledge: You should be comfortable writing and running Python scripts, understanding data types, and using loops and conditionals.
• Object-Oriented Programming (OOP): A good grasp of classes and objects is essential since we’ll use OOP concepts extensively.
• File Handling: Basic familiarity with reading from and writing to files in Python will be beneficial.

If you’re ready, let’s get started!

Setting Up the Project

Creating the Main Script File

Start by creating a new directory named AdvancedBankingSystem. Inside this directory, create a Python file named main.py. This will serve as the entry point for our banking system.

Importing Necessary Modules

Open main.py and import the necessary modules:

import os
import json
import hashlib
import getpass

Designing the Banking System

Defining Requirements

Our advanced banking system will support the following features:

• Creating a new account
• Viewing account details
• Depositing money
• Withdrawing money
• Saving account data to a file
• Loading account data from a file
• Secure password protection for accounts

Planning the Class Structure

We’ll use two main classes for our project:

1. Account: Represents a single bank account.
2. BankingSystem: Manages multiple accounts and provides the interface for user interactions.

Implementing the Account Class

Attributes and Methods

The Account class will have the following attributes:

• account_number: Unique identifier for the account
• name: Account holder’s name
• balance: Current balance of the account
• password: Encrypted password for secure access

The methods will include:

• __init__: Initializes a new account
• encrypt_password: Encrypts the password
• check_password: Checks if a provided password matches the stored one
• deposit: Adds money to the account
• withdraw: Removes money from the account if sufficient balance is available
• get_details: Returns the account details

Creating the Account Class

Open main.py and add the following code to define the Account class:

class Account:
    def __init__(self, account_number, name, password, initial_balance=0.0):
        self.account_number = account_number
        self.name = name
        self.balance = initial_balance
        self.password = self.encrypt_password(password)

    def encrypt_password(self, password):
        return hashlib.sha256(password.encode()).hexdigest()

    def check_password(self, password):
        return self.encrypt_password(password) == self.password

    def deposit(self, amount):
        if amount > 0:
            self.balance += amount
            return True
        return False

    def withdraw(self, amount):
        if 0 < amount <= self.balance:
            self.balance -= amount
            return True
        return False

    def get_details(self):
        return {
            'account_number': self.account_number,
            'name': self.name,
            'balance': self.balance
        }

Implementing the Banking System Class

Attributes and Methods

The BankingSystem class will manage multiple accounts and provide methods to interact with these accounts:

• __init__: Initializes the banking system with an empty account list
• create_account: Creates a new account
• authenticate_account: Verifies account credentials
• get_account: Retrieves an account by account number
• save_accounts: Saves all accounts to a file
• load_accounts: Loads accounts from a file
• display_accounts: Displays all accounts

Creating the Banking System Class

Add the following code to main.py to define the BankingSystem class:

class BankingSystem:
    def __init__(self):
        self.accounts = {}

    def create_account(self, account_number, name, password, initial_balance=0.0):
        if account_number not in self.accounts:
            account = Account(account_number, name, password, initial_balance)
            self.accounts[account_number] = account
            return True
        return False

    def authenticate_account(self, account_number, password):
        account = self.accounts.get(account_number)
        if account and account.check_password(password):
            return account
        return None

    def get_account(self, account_number):
        return self.accounts.get(account_number)

    def save_accounts(self, filename):
        with open(filename, 'w') as file:
            json.dump({acc: self.accounts[acc].get_details() for acc in self.accounts}, file)

    def load_accounts(self, filename):
        if os.path.exists(filename):
            with open(filename, 'r') as file:
                accounts_data = json.load(file)
                for acc_number, acc_details in accounts_data.items():
                    self.accounts[acc_number] = Account(acc_details['account_number'], acc_details['name'], "", acc_details['balance'])

    def display_accounts(self):
        for account in self.accounts.values():
            print(f"Account Number: {account.account_number}, Name: {account.name}, Balance: {account.balance}")

Adding File Handling

Saving Account Data to a File

In the BankingSystem class, the save_accounts method will save all account data to a JSON file. This allows us to persist the data even after the program exits.

Loading Account Data from a File

The load_accounts method will read the account data from a JSON file and recreate the Account objects.

Creating the User Interface

Command-line Interface

We’ll create a simple command-line interface to interact with the banking system. The user will be able to choose from a menu of options to perform different actions.

Menu Options for Users

We will provide the following menu options:

1. Create a new account
2. View account details
3. Deposit money
4. Withdraw money
5. Save accounts to file
6. Load accounts from file
7. Display all accounts
8. Exit

Implementing the User Interface

Add the following code to main.py to implement the command-line interface:

def main():
    banking_system = BankingSystem()
    while True:
        print("\n--- Banking System Menu ---")
        print("1. Create a new account")
        print("2. View account details")
        print("3. Deposit money")
        print("4. Withdraw money")
        print("5. Save accounts to file")
        print("6. Load accounts from file")
        print("7. Display all accounts")
        print("8. Exit")

        choice = input("Enter your choice: ")

        if choice == '1':
            account_number = input("Enter account number: ")
            name = input("Enter account holder name: ")
            password = getpass.getpass("Enter a password for the account: ")
            initial_balance = float(input("Enter initial balance: "))
            if banking_system.create_account(account_number, name, password, initial_balance):
                print("Account created successfully.")
            else:
                print("Account number already exists.")

        elif choice == '2':
            account_number = input("Enter account number: ")
            password = getpass.getpass("Enter password: ")
            account = banking_system.authenticate_account(account_number, password)
            if account:
                print(account.get_details())
            else:
                print("Authentication failed. Check account number or password.")

        elif choice == '3':
            account_number = input("Enter account number: ")
            password = getpass.getpass("Enter password: ")
            account = banking_system.authenticate_account(account_number, password)
            if account:
                amount = float(input("Enter amount to deposit: "))
                if account.deposit(amount):
                    print("Deposit successful.")
                else:
                    print("Deposit failed. Check the amount.")
            else:
                print("Authentication failed. Check account number or password.")

        elif choice == '4':
            account_number

 = input("Enter account number: ")
            password = getpass.getpass("Enter password: ")
            account = banking_system.authenticate_account(account_number, password)
            if account:
                amount = float(input("Enter amount to withdraw: "))
                if account.withdraw(amount):
                    print("Withdrawal successful.")
                else:
                    print("Withdrawal failed. Check the amount.")
            else:
                print("Authentication failed. Check account number or password.")

        elif choice == '5':
            filename = input("Enter filename to save accounts: ")
            banking_system.save_accounts(filename)
            print("Accounts saved successfully.")

        elif choice == '6':
            filename = input("Enter filename to load accounts: ")
            banking_system.load_accounts(filename)
            print("Accounts loaded successfully.")

        elif choice == '7':
            banking_system.display_accounts()

        elif choice == '8':
            print("Exiting the banking system. Goodbye!")
            break

        else:
            print("Invalid choice. Please try again.")

if __name__ == "__main__":
    main()

Testing the System

Creating Test Cases

To ensure our banking system works as expected, we need to test each functionality thoroughly. Here are some test cases to consider:

• Creating multiple accounts with different account numbers.
• Viewing account details for existing and non-existing accounts.
• Depositing money into an account and verifying the balance.
• Withdrawing money from an account and verifying the balance.
• Saving and loading account data from a file.

Running the System

Run the main.py script to start the banking system. Test each menu option to ensure everything works as intended.

In this tutorial, we’ve built an advanced and functional banking system using Python. We’ve covered essential programming concepts such as object-oriented programming, file handling, and command-line interfaces, and added security features like password protection. This project serves as a solid foundation for more advanced applications and enhancements.

Next Steps and Further Improvements

Here are some ideas for further improvements:

• Security Enhancements: Implement more advanced security measures, such as two-factor authentication.
• GUI Integration: Develop a graphical user interface (GUI) using libraries like Tkinter or PyQt to make the system more user-friendly.
• Database Integration: Replace JSON file handling with a robust database system like SQLite, MySQL, or PostgreSQL for better scalability.
• Advanced Banking Features: Add functionalities such as fund transfers between accounts, transaction history, and interest calculations.

By exploring these enhancements, you can continue to improve your programming skills and create even more sophisticated applications.

FAQs

How can I extend this banking system?

You can extend this banking system by adding more features such as account authentication, account transfers, and detailed transaction history. You can also switch from file-based storage to a database for better scalability and performance.

Is this banking system secure?

This basic banking system includes some security features like password protection but is not secure enough for real-world use. Implementing encryption, user authentication, and other advanced security measures is necessary to protect sensitive data.

Can I use this code for a real banking application?

This tutorial is meant for educational purposes and demonstrates the basics of building a banking system. A real banking application would require much more rigorous development, security, and testing to ensure it meets all necessary standards and regulations.

How can I add a graphical user interface (GUI) to this system?

You can add a GUI to this system using Python libraries such as Tkinter, PyQt, or Kivy. This will make the system more user-friendly and visually appealing.

What are the benefits of integrating a database?

Integrating a database like SQLite, MySQL, or PostgreSQL provides better data management, scalability, and performance. It allows for more efficient data retrieval and storage, making the system more robust and capable of handling larger datasets.