MySQL & Sequelize (ORM)

Using Eggjs to connect MySQL can use Sequelize

Sequelize is a widely used ORM framework that supports multiple data sources such as MySQL, PostgreSQL, SQLite, and MSSQL.

npm install --save egg-sequelize mysql2
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Configure the plug-in

config/plugin.js

sequelize: {
  enable: true.package: 'egg-sequelize',},Copy the code

Set the parameters

config/config.default.js

// sequelize
config.sequelize = {
  dialect: 'mysql'.host: '127.0.0.1'.port: 3306.database: 'egg-db'.username: 'root'.// Database user name
  password: '12345678'.// Database password
  timezone: '+ 08:00'.// Set the time zone
  define: {
    timestamps: true.// Automatically write the timestamp created_at updated_at
    paranoid: true.// Field generation soft delete timestamp deleted_at
    underscored: true.// Format all humps}};Copy the code

Creating a database

CREATE DATABASE IF NOT EXISTS `egg-db`;
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Data migration

Sequelize provides the sequelize-CLI tool to implement Migrations

Install sequelize – cli

npm install --save-dev sequelize-cli
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Place all migrations-related content in the Database directory and create a new.Sequelizerc configuration file in the project root directory

.sequelizerc

'use strict';

const path = require('path');

module.exports = {
  config: path.join(__dirname, 'database/config.json'),
  'migrations-path': path.join(__dirname, 'database/migrations'),
  'seeders-path': path.join(__dirname, 'database/seeders'),
  'models-path': path.join(__dirname, 'app/model'),};Copy the code

Initializes Migrations configuration files and directories

npx sequelize init:config
npx sequelize init:migrations
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The database/config.json file and the database/migrations directory are generated

Modify the contents of database/config.json to change it to the database configuration used in the project

database/config.json

{
  "development": {
    "dialect": "mysql"."host": "127.0.0.1"."port": 3306."database": "egg-db"."username": "root"."password": "12345678"
  },
  "test": {
    "username": "root"."password": null."database": "database_test"."host": "127.0.0.1"."dialect": "mysql"
  },
  "production": {
    "username": "root"."password": null."database": "database_production"."host": "127.0.0.1"."dialect": "mysql"}}Copy the code

Create and write a Migration file to create the table

npx sequelize migration:generate --name=init-users
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A migration file (${timestamp}-init-users.js) is generated in the database/migrations directory.

database/migrations/202104****-init-users.js

'use strict';

module.exports = {
  // The function that is called when performing the database upgrade to create the Users table
  up: async (queryInterface, Sequelize) => {
    const { INTEGER, STRING, DATE, DECIMAL } = Sequelize;
    await queryInterface.createTable('users', {
      id: { type: INTEGER, primaryKey: true.autoIncrement: true },
      user_name: {
        type: STRING,
        allowNull: false.unique: true.comment: 'Username, unique',},pass_word: STRING,
      gender: {
        type: DECIMAL,
        allowNull: false.defaultValue: 3.comment: 'Sex (1 male, 2 female, 3 Confidential)',},birthday: DATE,
      city: STRING,
      picture: STRING,
      created_at: DATE,
      updated_at: DATE,
      deleted_at: DATE,
    });
  },

  down: async queryInterface => {
    await queryInterface.dropTable('users'); }};Copy the code

Execute MIGRATE to create tables

Update database
npx sequelize db:migrate
If you have problems and need to roll back a change, use 'db:migrate:undo' to roll back a change
# npx sequelize db:migrate:undo
You can use 'db:migrate:undo:all' to revert to the initial state
# npx sequelize db:migrate:undo:all
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Practice the demo

The user table is concerned about the one-to-many relationship between users’ fans in the table

Create a concern table

npx sequelize migration:generate --name=init-userfollows
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Write the Migration

database/migrations/202104****-init-Userfollow.js

'use strict';

module.exports = {
  up: async (queryInterface, Sequelize) => {
    const { INTEGER, DATE } = Sequelize;
    await queryInterface.createTable('userfollows', {
      id: { type: INTEGER, primaryKey: true.autoIncrement: true },
      user_id: {
        type: INTEGER,
        allowNull: false.comment: 'User ID',},follower_id: {
        type: INTEGER,
        allowNull: false.comment: 'Id of the user being followed'.// Foreign key user table ID
        references: {
          model: 'users'.key: 'id',}},created_at: DATE,
      updated_at: DATE,
      deleted_at: DATE,
    });
  },

  down: async queryInterface => {
    await queryInterface.dropTable('userfollows'); }};Copy the code

Update database
npx sequelize db:migrate
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Create a relationship model of concern

app/model/userfollow.js

'use strict';

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

  const Userfollow = app.model.define('userfollows', {
    id: { type: INTEGER, primaryKey: true.autoIncrement: true },
    userId: INTEGER,
  });

  Userfollow.associate = () = > {
    // One-to-one relationship Each followerId corresponds to one user
    Userfollow.belongsTo(app.model.User, {
      foreignKey: 'followerId'.targetKey: 'id'}); };return Userfollow;
};
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Creating a user model

app/model/users.js

'use strict';

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

  const User = app.model.define('users', {
    id: { type: INTEGER, primaryKey: true.autoIncrement: true },
    userName: {
      type: STRING,
      allowNull: false.unique: true.comment: 'Username, unique',},passWord: STRING,
    gender: {
      type: DECIMAL,
      allowNull: false.defaultValue: 3.comment: 'Sex (1 male, 2 female, 3 Confidential)',},birthday: DATE,
    city: STRING,
    picture: STRING,
  });

  User.associate = () = > {
    // One-to-many relationship a user has multiple followers
    User.hasMany(app.model.Userfollow, {
      foreignKey: 'userId'.targetKey: 'followerId'}); };return User;
};

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Realize query fans, concern API

Query a user’s fans

app/controller/userfollow.js

// Get the list of fans
async getFans() {
  const { ctx } = this;
  const data = await ctx.service.userfollow.getUsersByFollower(ctx.params.id, ctx.request.query);
  ctx.body = { status: true.msg: 'Fan list obtained success', data };
}
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app/service/userfollow.js

/ / * * *
const { Op } = require('sequelize');
const { toInt } = require('.. /extend/utils'); // toInt Converts a string to a numeric type
/ / * * *

async getUsersByFollower(followerId, query) {
  const { pageNumber = 1, pageSize = 10 } = query;
  const result = await this.ctx.model.User.findAndCountAll({
    limit: toInt(pageSize),
    offset: toInt(pageSize) * (toInt(pageNumber) - 1),
    attributes: [ 'id'.'userName'.'picture'.'city'.'gender'].order: [[ 'id'.'desc' ]],
    include: [{model: this.ctx.model.Userfollow,
        attributes: [].where: {
          followerId,
          userId: {
            [ Op.ne]: followerId,
          },
        },
      },
    ],
  });
  return result;
}
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Query user concerns

app/controller/userfollow.js

// Get the list of concerns
async getFollowers() {
  const { ctx } = this;
  const data = await ctx.service.userfollow.getFollowersByUser(ctx.params.id, ctx.request.query);
  ctx.body = { status: true.msg: 'Concern list obtained successfully', data };
}
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app/service/userfollow.js

async getFollowersByUser(userId, query) {
  const { pageNumber = 1, pageSize = 10 } = query;
  const result = await this.ctx.model.Userfollow.findAndCountAll({
    limit: toInt(pageSize),
    offset: toInt(pageSize) * (toInt(pageNumber) - 1),
    order: [[ 'id'.'desc' ]],
    attributes: [].include: [{model: this.ctx.model.User,
        attributes: [ 'id'.'userName'.'picture'.'city'.'gender'],},],where: {
      userId,
      followerId: {
        [Op.ne]: userId,
      },
    },
  });
  return result;
}
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routing

app/router.js

router.get('/api/v1/user/:id/fans', controller.userfollow.getFans); // Get the user's fan list
router.get('/api/v1/user/:id/follow', controller.userfollow.getFollowers); // Get the user's concern list
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Insert some test data into the table

// ***
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Access to the routing

/ / GET http://127.0.0.1:7001/api/v1/user/1/fans? pageNumber=1&pageSize=10
{
    "status": true."msg": "Fan list success"."data": {
        "count": 2."rows": [{"id": 3."userName": "test3"."picture": null."city": "Hangzhou"."gender": "1"
            },
            {
                "id": 2."userName": "test2"."picture": null."city": "Shanghai"."gender": "3"}}}]/ / http://127.0.0.1:7001/api/v1/user/3/follow? pageNumber=1&pageSize=10
{
    "status": true."msg": "Focus list success"."data": {
        "count": 1."rows": [{"user": {
                    "id": 1."userName": "test1"."picture": null."city": "Beijing"."gender": "3"}},]}}Copy the code

Sequelize crud

increase

const result = await this.ctx.model.Userfollow.create({
  userId,
  followerId,
});
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delete

const result = await this.ctx.model.Userfollow.destroy({
  where: {
    userId,
    followerId,
  },
});
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change

// ...
const user = await this.ctx.model.User.findByPk(id);
// ...
await user.update({ userName, gender, birthday, city, picture });
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check

const result = await this.ctx.model.Userfollow.findOne({
  where: {
    userId,
    followerId,
  },
});
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For more information on Sequelize usage, visit www.sequelize.com.cn/

—END—

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Eggjs operates MySQL using the Sequelize (ORM) plug-in

MySQL & Sequelize (ORM)

Configure the plug-in

Set the parameters

Creating a database

Data migration

Install sequelize – cli

Initializes Migrations configuration files and directories

Create and write a Migration file to create the table

Execute MIGRATE to create tables

Practice the demo

The user table is concerned about the one-to-many relationship between users’ fans in the table

Create a concern table

Create a relationship model of concern

Creating a user model

Realize query fans, concern API

Query a user’s fans

Query user concerns

routing

Insert some test data into the table

Access to the routing

Sequelize crud

increase

delete

change

check

Eggjs operates MySQL using the Sequelize (ORM) plug-in

MySQL & Sequelize (ORM)

Configure the plug-in

Set the parameters

Creating a database

Data migration

Install sequelize – cli

Initializes Migrations configuration files and directories

Create and write a Migration file to create the table

Execute MIGRATE to create tables

Practice the demo

The user table is concerned about the one-to-many relationship between users’ fans in the table

Create a concern table

Create a relationship model of concern

Creating a user model

Realize query fans, concern API

Query a user’s fans

Query user concerns

routing

Insert some test data into the table

Access to the routing

Sequelize crud

increase

delete

change

check

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