Building a Restful CRUD API with Node.js, Express, and Sequelize

How to build a REST API with Node.js and Sequelize

Hi, in this article, we’ll be building a RESTful CRUD (Create, Retrieve, Update, Delete) API with Node.js, Express, and MySQL.

We’ll use Sequlize for interacting with the MySQL Database.

Prerequisites

• Node JS installed on your PC.
• MySQL installed on your PC.
• A text editor or IDE of your choice.
• Postman

We will build Rest API for creating, retrieving, updating & deleting users.

What is Sequelize?

Sequelize is a promise-based Node.js ORM(Object–relational mapping) for Postgres, MySQL, MariaDB, SQLite, and Microsoft SQL Server. It features solid transaction support, relations, eager and lazy loading, read replication, and more.

Creating The Application And Install Dependencies

first thing first let’s create our project folder.

$ mkdir nodejs-sequelize
$ cd nodejs-sequelize
$ npm init

next, we will install the required modules.

$ npm install express mysql2 sequelize sequelize-cli

• express: One of the most popular web frameworks for Node.js.
• mysql2: Fast MySQL driver.
• sequelize: A powerful library in Javascript that makes it easy to manage a SQL database.
• sequelize-cli: Sequelize Command-Line Interface (CLI).

To create the project you will need to execute the init command

npx sequelize-cli init

This will create the following folders:

Folder Structure

• config: contains config file, which tells CLI how to connect with database.
• models: contains all models for your project.
• migrations: contains all migration files.
• seeders: contains all seed files.

Connect To The Database

Create a database called usersdb so that we can connect to it.

Now, we need to tell the CLI how to connect to the database, to do that we need to edit the config.json file.

"development": {
"username": "root",
"password": "password",
"database": "usersdb",
"host": "localhost",
"dialect": "mysql"
}

Creating the Users Model

So, the first thing you need to understand is that whit Sequlize we create different tables as models, so instead of creating or table directly using SQL, let’s create a file called User.js in the models folder.

Now that we have a User model, let’s take a look at the app.js file.

The above code runs our server on port 3000 and we call the db.sequelize.sync() function to synchronize all the defined models to the database.

CRUD Operation

Creating a new User

the .create method used to insert a user into the database, based on the passed parameters.

Retrieving all Users

Retrieve all users from the database.

Retrieving a single User

Find a single user with a user id.

Updating a User

The .findByPk() method used to search for an entity whit the given primary key.

Deleting a User

We use .findByPk() to find a specific user by ID. Then, the .destroy() method removes the user from the database.

Testing our APIs

Creating a new User using POST /users API

Retrieve all Users using GET /users API

Retrieve a single User by id using GET /users/:id API

Update a User using PUT /users/:id API

Delete a User using DELETE /users/:id API

If you enjoyed this article, please tell a friend about it!

You can contact me through Twitter or Linkedin.

The entire project is available on GitHub.

Thanks for your reading.

Resources

https://sequelize.org/v4/manual/installation/getting-started

https://sequelize.org/master/manual/migrations.html