ORM for JavaScript (Node.js): Comparison and Examples

ORM for JavaScript (Node.js): comparison and examples

In modern web development with Node.js, interaction with databases (DB) is one of the key tasks. Using pure SQL code can be effective, but often leads to duplication, errors, and maintenance difficulties. This is where ORM (Object-Relational Mapping) comes to the rescue — tools that allow you to work with database tables as regular JavaScript objects. In this article, we will look at three most popular ORMs for Node.js: Sequelize, TypeORM, and Prisma, compare their features, and provide practical examples.

What is ORM and why is it needed?

ORM (Object-Relational Mapping) is a technology that connects relational databases with an object-oriented programming language. Instead of writing SQL queries, you manipulate objects and their methods. This provides several advantages:

• Database abstraction: You can easily switch between PostgreSQL, MySQL, SQLite without changing business logic.
• Security: ORM automatically escapes data, protecting against SQL injections.
• Convenience: Less boilerplate code, automatic migrations, data validation.
• Relationship support: Simple definition of relations (one-to-one, one-to-many, many-to-many).

1. Sequelize

Sequelize is one of the oldest and most mature ORMs for Node.js. It supports PostgreSQL, MySQL, MariaDB, SQLite, and Microsoft SQL Server. Sequelize uses an object-oriented approach and is based on promises.

Key features:

• Flexible system of migrations and seeders (filling with test data).
• Support for transactions, raw queries, and hooks (model lifecycle).
• Large community and many ready-made solutions.

Code example (Node.js):

const { Sequelize, DataTypes } = require('sequelize');

// Connecting to DBconst sequelize = new Sequelize('database', 'username', 'password', {  host: 'localhost',  dialect: 'postgres'});

// Defining a modelconst User = sequelize.define('User', {  name: {    type: DataTypes.STRING,    allowNull: false  },  email: {    type: DataTypes.STRING,    unique: true  }});

// Creating a recordasync function createUser() {  await sequelize.sync(); // Synchronizing model with DB  const user = await User.create({ name: 'Ivan', email: 'ivan@example.com' });  console.log('User created:', user.toJSON());}

createUser().catch(console.error);

2. TypeORM

TypeORM is an ORM created with a focus on TypeScript, but also works with plain JavaScript. It supports the same databases as Sequelize, plus MongoDB (via experimental mode). TypeORM uses decorators (for TypeScript) and an active record approach (Active Record) or Data Mapper.

Key features:

• Full TypeScript support with autocompletion and type checking.
• Two patterns: Active Record (methods on the model) and Data Mapper (repositories).
• Automatic migrations based on entity changes.

Code example (Node.js + TypeScript):

import { Entity, PrimaryGeneratedColumn, Column, createConnection } from "typeorm";

@Entity()export class User {  @PrimaryGeneratedColumn()  id: number;

  @Column()  name: string;

  @Column({ unique: true })  email: string;}

// Usageasync function main() {  const connection = await createConnection({    type: "postgres",    host: "localhost",    database: "test",    entities: [User],    synchronize: true, // Auto-creating tables (not for production!)  });

  const user = new User();  user.name = "Maria";  user.email = "maria@example.com";  await