Setup

In this tutorial, Sequelize will be used with MySQL.

To begin, make sure you have a database ready to use.

CREATE DATABASE IF NOT EXISTS `sequelize_tutorial`;

Then, in a project, install Sequelize and the necessary libraries.

npm i sequelize mysql2

Structure

You can see the demo server in this repo.

Configurations

You should use a .env file to store your database login credentials.

Create a .env file in the root project folder.

PORT=8080
DB_HOST=
DB_NAME=sequelize_tutorial
DB_PORT=
DB_USER=
DB_PASSWORD=

Connecting to the Database

Having set your credentials in .env, you should have a config file that gets those credentials from the .env file.

In config.js:

require('dotenv').config();

module.exports = {
    port: process.env.PORT,
    db: {
        host: process.env.DB_HOST,
        name: process.env.DB_NAME,
        port: process.env.DB_PORT,
        user: process.env.DB_USER,
        password: process.env.DB_PASSWORD
    }
};

With these credentials, we can now create a new connection with Sequelize to the database.

In connection.js:

const { Sequelize } = require('sequelize');
const { name, user, password, host, port } = require('./config').db;

const db = new Sequelize(name, user, password, {
    host, port, dialect: 'mysql'
});

module.exports = db;

Models Syncing

In the project entry file, we can get Sequelize to sync our database tables with the models we define.

In index.js:

// immediately invoked function here to use async/await
(async function main() {
    try {
        // connect to database
        await db.authenticate();

        // sync the database to our models
        await db.sync(/* options */);
    }
    catch (error) {
        // fail
    }

    // ...
})();