node.js - Sequelize 和 module.exports

Question

我是 nodejs 和 Sequelize 的新手，并且遇到了一个我无法弄清楚如何克服的问题。我想使用我创建的连接并将其导出到模块。

像这样:

const dotEnv        = require('dotenv');
const Sequelize     = require('sequelize');

dotEnv.config();

module.exports.connection = async () => {
    try{
        const sequelize = new Sequelize(process.env.DB_DATABASE, process.env.DB_USER, process.env.DB_PASSWORD, {
            host: process.env.DB_HOST,
            port: process.env.DB_PORT,
            dialect: 'mysql',
            logging: false,
            define: {
                charset: 'utf8',
                collate: 'utf8_general_ci',
            },
        });
        await sequelize
        .authenticate()
        .then(() => {
            console.log('Connection has been established successfully.');
        })
        .catch(error => {
            throw error;
        });
    }catch(error){
        throw error;
    }
}

然后我有另一个文件，我想在其中使用它，看起来像这样

const Sequelize     = require('sequelize');
const { connection }= require('../database');

const accountModel = connection.define('accounts', {
  // attributes
  id: {
      type: Sequelize.UUID,
      defaultValue: Sequelize.UUIDV4,
      primaryKey: true
  },
  name: {
    type: Sequelize.STRING,
    allowNull: false
  },
  email: {
      type: Sequelize.STRING,
      unique: true
  },
  password: {
      type: Sequelize.STRING,
      allowNull: false,
      //is: /^[0-9a-f]{64}$/i
  },
  permission: {
      type: Sequelize.STRING,
      allowNull: false
  },
  discount: {
      type: Sequelize.INTEGER,
      allowNull: false
  }
}, {
  freezeTableName: true
});
module.exports = connection.model('accounts', accountModel);

问题是我被告知: TypeError: connection.define is not a function，

连接正常，数据库正在运行，其他一切正常
最后，如果我这样做，它也可以:

const dotEnv        = require('dotenv');
const Sequelize     = require('sequelize');

dotEnv.config();

const sequelize = new Sequelize(process.env.DB_DATABASE, process.env.DB_USER, process.env.DB_PASSWORD, {
    host: process.env.DB_HOST,
    port: process.env.DB_PORT,
    dialect: 'mysql',
    logging: false,
    define: {
        charset: 'utf8',
        collate: 'utf8_general_ci',
    },
});

const accountModel = sequelize.define('accounts', {
  // attributes
  id: {
      type: Sequelize.UUID,
      defaultValue: Sequelize.UUIDV4,
      primaryKey: true
  },
  name: {
    type: Sequelize.STRING,
    allowNull: false
  },
  email: {
      type: Sequelize.STRING,
      unique: true
  },
  password: {
      type: Sequelize.STRING,
      allowNull: false,
      //is: /^[0-9a-f]{64}$/i
  },
  permission: {
      type: Sequelize.STRING,
      allowNull: false
  },
  discount: {
      type: Sequelize.INTEGER,
      allowNull: false
  }
}, {
  freezeTableName: true
});
module.exports = sequelize.model('accounts', accountModel);

我真的不确定为什么模块一不起作用，但直接方法起作用。我曾尝试在 Google 和 Stack Overflow 上搜索解决方案。

Answer 1

第一种方法的问题是您首先导出了 async function而不是 Sequelize instance (就像你的第二个例子一样)其次，函数本身没有返回任何东西。这就是为什么没有connection.define()当您在另一个文件中需要它时起作用。

试试这个 database.js它应该工作:

module.exports.connection = new Sequelize(process.env.DB_DATABASE, process.env.DB_USER, process.env.DB_PASSWORD, {
            host: process.env.DB_HOST,
            port: process.env.DB_PORT,
            dialect: 'mysql',
            logging: false,
            define: {
                charset: 'utf8',
                collate: 'utf8_general_ci',
            },
        });

你可以做到 authenticate()和 try {} catch (error) {}其他地方，例如在你的第一个 js通过要求相同的 database.js 来启动服务器的文件文件。但是对于模型定义，您只导出 new Sequelize() 很重要。实例让他们能够使用 define()