mysql三级联动城市表

CREATE TABLE provinces (
  id INT PRIMARY KEY AUTO_INCREMENT,
  name VARCHAR(50) NOT NULL
);

CREATE TABLE cities (
  id INT PRIMARY KEY AUTO_INCREMENT,
  name VARCHAR(50) NOT NULL,
  province_id INT,
  FOREIGN KEY (province_id) REFERENCES provinces(id)
);

CREATE TABLE districts (
  id INT PRIMARY KEY AUTO_INCREMENT,
  name VARCHAR(50) NOT NULL,
  city_id INT,
  FOREIGN KEY (city_id) REFERENCES cities(id)
);

// 获取省份下拉菜单
function getProvinces() {
  fetch('/api/provinces')
    .then(response => response.json())
    .then(data => {
      // 更新省份下拉菜单
    });
}

// 获取市下拉菜单
function getCities(provinceId) {
  fetch(`/api/cities?provinceId=${provinceId}`)
    .then(response => response.json())
    .then(data => {
      // 更新市下拉菜单
    });
}

// 获取区下拉菜单
function getDistricts(cityId) {
  fetch(`/api/districts?cityId=${cityId}`)
    .then(response => response.json())
    .then(data => {
      // 更新区下拉菜单
    });
}

const express = require('express');
const app = express();

// 获取省份列表
app.get('/api/provinces', (req, res) => {
  // 查询数据库并返回省份列表
});

// 获取市列表
app.get('/api/cities', (req, res) => {
  const provinceId = req.query.provinceId;
  // 根据省份ID查询数据库并返回市列表
});

// 获取区列表
app.get('/api/districts', (req, res) => {
  const cityId = req.query.cityId;
  // 根据市ID查询数据库并返回区列表
});

app.listen(3000, () => {
  console.log('Server is running on port 3000');
});