Node.js TypeError:无法读取属性'；定义'；未定义的

我尝试将我的Db从mongodb更改为mysql，我使用sequelize而不是mongoose，我得到了这个错误，我创建了User.js模型，使用sequelize格式，但出现了一些错误，我不知道为什么

const User = sequelize.define('users', {
                   ^

TypeError: Cannot read property 'define' of undefined"

这是我的密码：

server.js

const Sequelize = require('sequelize');       
// DB Config
const db = require('./config/keys');
// Connect to MySql
const sequelize = new Sequelize(db.database, db.user, db.password, {
    host: db.host,
    dialect: 'mysql',
    port: db.port
});

// Test the connection
sequelize
  .authenticate()
  .then(() => {
    console.log('Connection has been established successfully.');
  })
  .catch(err => {
    console.error('Unable to connect to the database:', err);
  });    
const serverDB = {};
serverDB.sequelize = sequelize;
serverDB.Sequelize = Sequelize;
module.exports = serverDB;

Users.js

const serverDB = require('../server');
const sequelize = serverDB.sequelize;
const Sequelize = serverDB.Sequelize;

const User = sequelize.define('users', {
        id: {
            type: Sequelize.INTEGER,
            primaryKey: true,
            autoIncrement: true
        },
        name: {
            type: Sequelize.STRING,
            allowNull: false
        },
        email: {
            type: Sequelize.STRING,
            allowNull: false
        },
        password: {
            type: Sequelize.STRING,
            allowNull: false
        },
        avatar: {
            type: STRING
        },
        date: {
            type: Sequelize.DATE,
            defaudefaultValue: Sequelize.NOW
        }
    });

sequelize.models.modelName

// sequelize.sync()
//     .then(() => {
//         console.log('User db and user table have been created')
//     });

module.exports = User;

你应该加上

const Sequelize = require('sequelize');

你的客户也是这样

并且只导出并使用小写的

sequelize

---

并确保server.js的相对路径良好。

您应该添加

const Sequelize=require（'Sequelize'）也在您的客户端中。并且只导出并使用小写的
sequelize
。仍然是相同的错误您确定server.js的相对路径吗？您检查了路径吗？我仍然不知道错误，但我已经修复了：））谢谢大家