Belajar Express JS | 14. Core Concepts Sequelize ORM

Sequelize is a powerful ORM (Object-Relational Mapping) tool for Node.js that provides an easy way to interact with databases. In this tutorial, we’ll be covering some core concepts of Sequelize ORM and how to use them in an Express.js application.

Setting up Sequelize

First and foremost, you’ll need to install Sequelize and its dependencies. You can do so by running the following command in your terminal:

npm install --save sequelize

Once Sequelize is installed, you’ll need to set up a connection to your database. In most cases, you’ll be using PostgreSQL, MySQL, or SQLite as your database. You can configure the database connection in a separate file, such as config.js, and then import it into your main application file.

Defining Models

After setting up the database connection, you’ll need to define the models for your application. Models are essentially JavaScript classes that represent tables in your database. You can define models for each table in your database, including their attributes and data types.

CRUD Operations with Sequelize

Sequelize provides a powerful set of methods for performing CRUD (Create, Read, Update, Delete) operations on your database. You can create new records, retrieve records based on certain criteria, update existing records, and delete records from your database using Sequelize methods.

Associations

One of the most powerful features of Sequelize is its support for associations between different models. You can define various types of associations, such as one-to-one, one-to-many, and many-to-many, to establish relationships between different tables in your database.

Validation and Hooks

Sequelize also provides support for data validation and hooks, allowing you to define constraints and trigger certain actions before or after performing CRUD operations. This can be extremely useful for maintaining data integrity and implementing business logic in your application.

Conclusion

Sequelize is a powerful and versatile ORM tool that can greatly simplify the process of interacting with databases in a Node.js application. In this tutorial, we’ve covered some core concepts of Sequelize ORM and how to use them in an Express.js application. By mastering these concepts, you’ll be well-equipped to build robust and scalable database-driven applications with Node.js and Express.js.