最近在接手一个项目，vue+nuxt+egg，我也是刚开始学习egg.js，所以会将自己踩的坑都记录下来。

安装mysql

使用sequelize连接数据库，首先安装egg-sequelize和mysql2。

npm install --save egg-sequelize mysql2

打开package.json文件，查看安装是否成功和对应的版本。

{
  "name": "enmo-admin-server",
  "version": "1.0.0",
  "description": "",
  "private": true,
  "egg": {
    "declarations": true
  },
  "dependencies": {
    "await-stream-ready": "^1.0.1",
    "egg": "^2.15.1",
    "egg-scripts": "^2.11.0",
    "egg-sequelize": "^5.2.1",
    "egg-swagger-doc": "^2.2.9",
    "egg-validate": "^2.0.2",
    "egg-view-assets": "^1.6.1",
    "egg-view-ejs": "^2.0.1",
    "lodash": "^4.17.11",
    "moment": "^2.24.0",
    "ms": "^2.1.1",
    "mysql2": "^2.1.0",
    "sha1": "^1.1.1"
  },
  "devDependencies": {
    "autod": "^3.0.1",
    "autod-egg": "^1.1.0",
    "egg-bin": "^4.11.0",
    "egg-ci": "^1.11.0",
    "egg-mock": "^3.21.0",
    "eslint": "^5.13.0",
    "eslint-config-egg": "^7.1.0",
    "sequelize-cli": "^6.1.0"
  },
  "engines": {
    "node": ">=10.0.0"
  },
  "scripts": {
    "start": "egg-scripts start --daemon --title=egg-server-enmo-admin-server",
    "stop": "egg-scripts stop --title=egg-server-enmo-admin-server",
    "dev": "egg-bin dev",
    "debug": "egg-bin debug",
    "test": "npm run lint -- --fix && npm run test-local",
    "test-local": "egg-bin test",
    "cov": "egg-bin cov",
    "lint": "eslint .",
    "ci": "npm run lint && npm run cov",
    "autod": "autod"
  },
  "ci": {
    "version": "10"
  },
  "repository": {
    "type": "git",
    "url": ""
  },
  "author": "",
  "license": "MIT"
}

在config/plugin.js中启用eggsequelize插件

// config/plugin.js
exports.sequelize = {
  enable: true,
  package: 'egg-sequelize',
};

在config/config.default.js中添加sequelize配置

// config/config.default.js
config.sequelize = {
  dialect: 'mysql',
  host: '127.0.0.1',
  port: 3306,
  database: 'egg-sequelize-doc-default',
  username: 'root',
  password: 'w123456',
}

在数据库中创建表并插入数据

在app/model/user.js中编写代码实现业务逻辑

// app/model/user.js
'use strict';

module.exports = app => {
  const {
    STRING,
    INTEGER,
  } = app.Sequelize;

  const User = app.model.define('user', {
    id: {
      type: INTEGER,
      primaryKey: true,
      autoIncrement: true,
    },
    name: STRING(50),
    sex: STRING(4),
    pass: STRING(32),
  }, {
    freezeTableName: true,
    timestamps: false,
  });

  return User;
};

这个Model就可以在Controller和Service中通过app.model.User访问，编写Controller调用这个Model

// app/controller/user.js
'use strict';

const Controller = require('egg').Controller;

class UserController extends Controller {
  async index() {
    const _ctx = this.ctx;
    const user = await _ctx.model.User.findAll();
    _ctx.body = user;
  }
}

module.exports = UserController;

将controller挂载到路由上

// app/router.js
module.exports = app => {
  const { router, controller } = app;
  router.resources('users', '/users', controller.users);
};

使用npm run dev命令启动项目。在localhost:7001/user看到数据库中的数据。