Mastering Order Processing Systems: A Comprehensive Guide to Building Efficient Business Solutions with Python

Part 4: Database Design and Initialization

Introduction

In any order processing system, the database plays a vital role as it serves as the foundation for storing and managing critical information such as user details, product inventory, and order data. A well-structured database ensures that the system is efficient, reliable, and scalable. In this part of the blog series, we’ll dive into the database schema used in the project, explain the role of each table, and demonstrate how to initialize the database using Python and SQLite.

Overview of the Database Schema

The database for our order processing system is designed to store information about users, products, orders, and the details of each order. Here's a high-level view of the key tables involved:

• users table: Stores user credentials and role information, ensuring that only authorized personnel can access the system.

• products table: Contains information about products such as product ID, name, price, and stock levels.

• orders table: Holds data related to customer orders, including order ID, customer name, order date, and status.

• order_details table: Records the specific items and quantities for each order.

• user_registrations table: Stores information about user registration requests, which are approved or rejected by an admin.

Each of these tables has been designed with specific fields to ensure the integrity of the data and support efficient order processing. Let's now take a deeper look at each of these tables.

Explanation of the Tables

1. Users Table

The users table is responsible for storing user credentials and roles. The role-based access control (admin, manager, employee) helps secure the system by ensuring that only authorized users can perform certain actions.

Here’s the structure of the users table:

2. Products Table

The products table stores essential information about the products available for purchase, including product identification, pricing, and inventory levels.

This table helps the system manage inventory levels and ensure that products are available for sale.

3. Orders Table

The orders table tracks high-level information about customer orders. This includes the order ID, customer details, and order status.

4. Order Details Table

The order_details table is used to track the specific items and their quantities within each order. This table links products to the orders.

The order_details table allows the system to manage orders containing multiple products.

5. User Registrations Table

The user_registrations table keeps track of users who have requested access to the system. Admins can approve or reject these registration requests.

This table supports the admin workflow for managing new user registrations.

Code Snippet: init_db() Function

The init_db() function is responsible for initializing the database and creating all the necessary tables. Let’s take a look at the code that sets up this schema in SQLite:

def init_db():
    conn = sqlite3.connect('order_system.db')
    c = conn.cursor()

    # Create Users Table
    c.execute('''
        CREATE TABLE IF NOT EXISTS users (
            user_id INTEGER PRIMARY KEY AUTOINCREMENT,
            username TEXT UNIQUE,
            password TEXT,
            role TEXT
        )
    ''')

    # Create User Registrations Table
    c.execute('''
        CREATE TABLE IF NOT EXISTS user_registrations (
            registration_id INTEGER PRIMARY KEY AUTOINCREMENT,
            username TEXT UNIQUE,
            password TEXT,
            email TEXT,
            role TEXT,
            status TEXT
        )
    ''')

    # Create Products Table
    c.execute('''
        CREATE TABLE IF NOT EXISTS products (
            product_id TEXT PRIMARY KEY,
            name TEXT,
            price REAL,
            stock INTEGER
        )
    ''')

    # Create Orders Table
    c.execute('''
        CREATE TABLE IF NOT EXISTS orders (
            order_id TEXT PRIMARY KEY,
            customer_name TEXT,
            date TEXT,
            status TEXT,
            order_status TEXT DEFAULT 'Processing'
        )
    ''')

    # Create Order Details Table
    c.execute('''
        CREATE TABLE IF NOT EXISTS order_details (
            order_id TEXT,
            product_id TEXT,
            quantity INTEGER,
            FOREIGN KEY(order_id) REFERENCES orders(order_id),
            FOREIGN KEY(product_id) REFERENCES products(product_id)
        )
    ''')

    conn.commit()
    conn.close()
    logging.info("Database initialized")

Running the Script to Create and Initialize the Database

To create and initialize the database, you simply need to run the init_db() function. This will create all the necessary tables and ensure that your database is ready for storing data.

Here’s how you can run the initialization script:

1. Create a Python script (e.g., db_setup.py) that contains the init_db() function.

2. Run the script in your terminal:

    python db_setup.py
   

3. Check the database: After running the script, you should find an order_system.db file in your project folder. You can use an SQLite database browser (such as DB Browser for SQLite) to view the tables and their structure.

Conclusion

In this part, we explored the database design of the order processing system, covering the schema and its key components. The init_db() function plays a crucial role in setting up the system’s foundation, ensuring that the database tables are created properly. Now that our database is initialized, we can begin building the functionality that interacts with these tables, starting with the user interface in the next part.

Stay tuned for the next part, where we’ll start learning how to Populate the Database with Initial Data.

Link to My Source code : https://github.com/BryanSJamesDev/-Order-Processing-System-OPS-/tree/main