扫码点餐小程序搭建流程详解：从桌码到订单系统如何实现

微信小程序
    ↓
Nginx负载均衡
    ↓
Java / PHP / Node服务
    ↓
MySQL + Redis
    ↓
支付、打印、短信等第三方服务

https://demo.com/order?table_id=102

CREATE TABLE restaurant_table (
    id INT PRIMARY KEY AUTO_INCREMENT,
    table_name VARCHAR(50),
    qr_code VARCHAR(255),
    status TINYINT DEFAULT 0,
    create_time TIMESTAMP DEFAULT CURRENT_TIMESTAMP
);

const QRCode = require('qrcode')

const url = 'https://demo.com/order?table_id=102'

QRCode.toFile('./table102.png', url, function (err) {
  if (err) throw err
  console.log('二维码生成成功')
})

CREATE TABLE food_category (
    id INT PRIMARY KEY AUTO_INCREMENT,
    name VARCHAR(50),
    sort INT DEFAULT 0
);

CREATE TABLE food (
    id INT PRIMARY KEY AUTO_INCREMENT,
    category_id INT,
    food_name VARCHAR(100),
    price DECIMAL(10,2),
    stock INT,
    image VARCHAR(255),
    status TINYINT DEFAULT 1
);

app.get('/api/menu', async (req, res) => {

    const category = await db.query('SELECT * FROM food_category')

    const foods = await db.query('SELECT * FROM food WHERE status=1')

    res.json({
        category,
        foods
    })
})

let cart = [
    {
        food_id: 1,
        food_name: "红烧肉",
        price: 38,
        number: 2
    }
]

function calcTotal(cart) {

    return cart.reduce((total, item) => {
        return total + item.price * item.number
    }, 0)

}

加入购物车
    ↓
提交订单
    ↓
锁定库存
    ↓
生成订单号
    ↓
微信支付
    ↓
通知后厨
    ↓
商家接单
    ↓
完成订单

CREATE TABLE food_order (
    id BIGINT PRIMARY KEY AUTO_INCREMENT,
    order_no VARCHAR(64),
    user_id INT,
    table_id INT,
    total_price DECIMAL(10,2),
    pay_status TINYINT DEFAULT 0,
    order_status TINYINT DEFAULT 0,
    create_time TIMESTAMP DEFAULT CURRENT_TIMESTAMP
);

app.post('/api/createOrder', async (req, res) => {

    const {
        user_id,
        table_id,
        foods
    } = req.body

    let totalPrice = 0

    foods.forEach(item => {
        totalPrice += item.price * item.number
    })

    const orderNo = 'FOOD' + Date.now()

    await db.query(`
        INSERT INTO food_order
        (order_no,user_id,table_id,total_price)
        VALUES (?,?,?,?)
    `, [orderNo, user_id, table_id, totalPrice])

    res.json({
        success: true,
        orderNo
    })

})

START TRANSACTION;

UPDATE food 
SET stock = stock - 1
WHERE id = 1 AND stock > 0;

COMMIT;

ROLLBACK;

用户提交订单
    ↓
服务端生成预支付订单
    ↓
返回支付参数
    ↓
小程序调起支付
    ↓
微信异步回调
    ↓
修改订单状态

const result = await wxpay.transactions_jsapi({
    description: '扫码点餐订单',
    out_trade_no: orderNo,
    notify_url: 'https://demo.com/pay/notify',
    amount: {
        total: 100
    },
    payer: {
        openid: openid
    }
})

订单号：20260518001

红烧肉 ×2
鱼香肉丝 ×1

总金额：88元
桌号：A08

const menu = await redis.get('menu')

用户下单
    ↓
进入MQ队列
    ↓
库存系统处理
    ↓
打印系统处理

upstream order_server {
    server 127.0.0.1:3000;
    server 127.0.0.1:3001;
}