How to develop a simple online ordering system using MySQL and Python

How to use MySQL and Python to develop a simple online ordering system

With the rapid development of the Internet, more and more people choose to order food online to solve their daily problems Dietary needs. In order to meet the needs of users, many companies have developed various online ordering systems. This article will introduce how to use MySQL and Python to develop a simple online ordering system and provide specific code examples.

First, we need to create a MySQL database to store menu information, user information and order information. The corresponding table can be created using the following SQL statement:

CREATE TABLE IF NOT EXISTS `menu` (
  `id` INT AUTO_INCREMENT PRIMARY KEY,
  `name` VARCHAR(100) NOT NULL,
  `price` DECIMAL(10,2) NOT NULL
);
CREATE TABLE IF NOT EXISTS `users` (
  `id` INT AUTO_INCREMENT PRIMARY KEY,
  `username` VARCHAR(100) NOT NULL,
  `password` VARCHAR(100) NOT NULL
);
CREATE TABLE IF NOT EXISTS `orders` (
  `id` INT AUTO_INCREMENT PRIMARY KEY,
  `user_id` INT NOT NULL,
  `menu_id` INT NOT NULL,
  `quantity` INT NOT NULL,
  `date` DATE NOT NULL
);

Next, we use Python and MySQL connection libraries to implement database connections and operations. The following is a code example for MySQL connection:

import mysql.connector

# 连接MySQL数据库
def connect_db():
    conn = mysql.connector.connect(
        host="localhost",
        user="your_username",
        password="your_password",
        database="your_database"
    )
    return conn

# 查询菜单
def get_menu():
    conn = connect_db()
    cursor = conn.cursor()
    cursor.execute("SELECT * FROM menu")
    menu = cursor.fetchall()
    cursor.close()
    conn.close()
    return menu

# 用户注册
def register(username, password):
    conn = connect_db()
    cursor = conn.cursor()
    cursor.execute("INSERT INTO users (username, password) VALUES (%s, %s)", (username, password))
    conn.commit()
    cursor.close()
    conn.close()

# 用户登录
def login(username, password):
    conn = connect_db()
    cursor = conn.cursor()
    cursor.execute("SELECT * FROM users WHERE username = %s AND password = %s", (username, password))
    user = cursor.fetchone()
    cursor.close()
    conn.close()
    return user

# 下订单
def place_order(user_id, menu_id, quantity, date):
    conn = connect_db()
    cursor = conn.cursor()
    cursor.execute("INSERT INTO orders (user_id, menu_id, quantity, date) VALUES (%s, %s, %s, %s)", (user_id, menu_id, quantity, date))
    conn.commit()
    cursor.close()
    conn.close()

Now we can query the menu from the database, implement user registration and login, and place orders.

In order for users to use the online ordering system, we need a simple user interface. The following is a code example using Python's Flask library to implement a simple web interface:

from flask import Flask, render_template, request
app = Flask(__name__)

# 用户界面
@app.route("/")
def index():
    menu = get_menu()
    return render_template("index.html", menu=menu)

# 用户注册
@app.route("/register", methods=["GET", "POST"])
def register_page():
    if request.method == "POST":
        username = request.form["username"]
        password = request.form["password"]
        register(username, password)
        return render_template("success.html")
    return render_template("register.html")

# 用户登录
@app.route("/login", methods=["GET", "POST"])
def login_page():
    if request.method == "POST":
        username = request.form["username"]
        password = request.form["password"]
        user = login(username, password)
        if user:
            return render_template("success.html")
        else:
            return render_template("login.html", error="Invalid username or password.")
    return render_template("login.html")

# 下订单
@app.route("/place_order", methods=["POST"])
def place_order_page():
    user_id = request.form["user_id"]
    menu_id = request.form["menu_id"]
    quantity = request.form["quantity"]
    date = request.form["date"]
    place_order(user_id, menu_id, quantity, date)
    return render_template("success.html")

if __name__ == "__main__":
    app.run()

The above code creates a simple web interface based on Flask, including the homepage, user registration page, user login page and order placement Page.

Finally, we need to create the corresponding html template file to present the web interface. Here is a simple example:

index.html:

<!DOCTYPE html>
<html>
<head>
    <title>Online Ordering System</title>
</head>
<body>
    {% for item in menu %}
        <h3>{{ item[1] }}</h3>
        <p>Price: {{ item[2] }}</p>
        <form action="/place_order" method="post">
            <input type="hidden" name="user_id" value="1">
            <input type="hidden" name="menu_id" value="{{ item[0] }}">
            <input type="number" name="quantity" min="1" max="10" placeholder="Quantity" required>
            <input type="date" name="date" required>
            <button type="submit">Order</button>
        </form>
        <hr>
    {% endfor %}
</body>
</html>

register.html:

<!DOCTYPE html>
<html>
<head>
    <title>User Registration</title>
</head>
<body>
    <h2>User Registration</h2>
    <form action="/register" method="post">
        <input type="text" name="username" placeholder="Username" required>
        <input type="password" name="password" placeholder="Password" required>
        <button type="submit">Register</button>
    </form>
</body>
</html>

login.html:

<!DOCTYPE html>
<html>
<head>
    <title>User Login</title>
</head>
<body>
    <h2>User Login</h2>
    {% if error %}
        <p style="color:red;">{{ error }}</p>
    {% end %}
    <form action="/login" method="post">
        <input type="text" name="username" placeholder="Username" required>
        <input type="password" name="password" placeholder="Password" required>
        <button type="submit">Login</button>
    </form>
</body>
</html>

success.html:

<!DOCTYPE html>
<html>
<head>
    <title>Success</title>
</head>
<body>
    <h2>Success</h2>
    <p>Your order has been placed successfully.</p>
</body>
</html>

The above is a detailed code example of how to use MySQL and Python to develop a simple online ordering system. By referring to this example, you can further expand and optimize your online ordering system to suit your actual needs.

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