A crucial component of creating modern applications is data persistence. The capacity to store and retrieve data is crucial for developing a web application, a mobile app, or any other software solution. Relational databases have been a common tool for developers to handle their data. Working directly with databases, however, can be difficult and time-consuming. Object-Relational Mapping (ORM) is useful in this situation.
A technique called object-relational mapping (ORM) makes it easier to translate objects from object-oriented programming languages like JavaScript to relational database tables. To let developers deal with objects and classes while the ORM takes care of the underlying database operations, it offers an abstraction layer. In this post, we’ll look at JavaScript’s ORM idea, its advantages, and how it makes data persistence easier.
Understanding Object-Relational Mapping (ORM)
The programming approach known as ORM, or object-relational mapping, gives users of object-oriented programming languages a way to interface with databases. An ORM transforms data between relational databases and programming languages that use objects.
An ORM creates objects that practically correspond to database tables. As a result, it is simple and more efficient to perform lengthy and complex SQL queries because you can quickly access, modify, or remove any field in the table.
A code library called an object-relational mapper contains the code required to manipulate the data, eliminating the need for SQL. You can directly communicate with an object in the language you’re using by writing an object-relational mapper.
When a data source or its API changes, only the ORM needs to adapt—not the applications that utilize the ORM—because it hides and encapsulates the change in the data source.
How object-relational mapping works
ORM translates the frequently complex codes and state information that object-oriented applications produce. Without understanding how the data is structured, it builds a structured map that illustrates how items relate to various tables (of data). In other words, it generates a highly abstract logical representation of the program without revealing the specifics of the underlying code.
Using relational databases, XML repositories, or other data sources and sinks as the foundation, ORM controls the specific mappings between a collection of objects and these sources and sinks. It simultaneously conceals from developers and the code they write the frequently changing specifics of associated interfaces. New technologies and capabilities can frequently be incorporated into ORM updates without requiring changes to the code of linked applications.
Using an ORM in JavaScript offers several benefits
- Simplified Database Operations: Developers don’t need to create SQL code since ORM technologies handle database transactions and construct the necessary SQL queries automatically. By handling the low-level specifics of database interactions, the ORM tool lowers the likelihood of errors and makes the code easier to maintain.
- Increased Productivity: The low-level mechanics of dealing with a database are abstracted away by ORM technologies, freeing developers to concentrate on creating business logic rather than SQL queries. Because developers can write and test code more quickly as a result of this change, development times are shortened.
- Improvements in Code Maintenance: By offering a standardized mechanism to build database models and relationships, ORM encourages clean and organized code. As the application becomes more sophisticated, this makes the codebase simpler to comprehend, alter, and maintain.
- Improves security: Built-in security features in ORM technologies assist prevent SQL injection attacks, a frequent security flaw in database-driven applications. Additionally, ORM solutions add an abstraction layer between the application code and the database, making it more challenging for attackers to take advantage of flaws.
Object-Relational Mapping drawbacks
- Steep learning curve: Developers unfamiliar with object-oriented programming ideas may find ORM tools to have a steep learning curve. It can take a lot of time and effort for developers to learn how to translate their object-oriented code to the database schema. Developers also need to understand how to use the unique syntax and APIs that different ORM solutions have.
- Slow performance speed: ORM solutions automatically create SQL queries, which may produce less efficient queries than those developed by a skilled SQL developer. Database-driven applications may function slower as a result of this lack of efficiency. Furthermore, ORM solutions frequently produce more database queries than are required, which can further hinder speed. Although ORM tools can make development more straightforward, they might not be the best option for applications that demand high performance or have stringent performance requirements.
Popular ORM Libraries in JavaScript
Sequelize
Sequelize is, in our opinion, one of the most popular open-source and easy-to-use Node.js and TypeScript ORM solutions for MySQL, Postgres, SQLite, SQL Server, MariaDB, etc. Data modeling is made easier for developers by enabling automatic database synchronization and linkages between data models. This software also handles labor-intensive activities without any issues. It can also reduce the amount of redundant code while minimizing costs and overall development time. Developers can connect different databases and swap between databases more simply when working on multiple applications when using Sequelize. However, we believe that Sequelize might have trouble with complex linkages and associations, and maintainability might also be an issue.
To install the dependencies for Sequelize, you can use npm, the package manager for Node.js. Here are the steps to install Sequelize and its required dependencies:
Open your command-line interface (e.g., Terminal, Command Prompt). Navigate to your project directory, where you want to install Sequelize. Run the following command to initialize a new Node.js project (if you haven’t already done so):
npm init -y
Install Sequelize and its required dependencies by running the following command:
npm install sequelize sequelize-cli mysql2
This command installs the sequelize, sequelize-cli, and mysql2 packages. The sequelize box is the core library for Sequelize, sequelize-cli provides the command-line interface for Sequelize, and mysql2 is the MySQL database driver. You can replace mysql2 with the appropriate database driver for your database system (e.g., pg for PostgreSQL, sqlite3 for SQLite).
Example:
const Sequelize = require('sequelize');
// Create a new Sequelize instance
const sequelize = new Sequelize('database', 'username', 'password', {
dialect: 'sqlite',
storage: 'database.sqlite'
});
// Define a model for a 'User' table
const User = sequelize.define('User', {
id: {
type: Sequelize.INTEGER,
autoIncrement: true,
primaryKey: true
},
name: {
type: Sequelize.STRING,
allowNull: false
},
age: {
type: Sequelize.INTEGER,
allowNull: false
}
});
// Synchronize the model with the database
sequelize.sync()
.then(() => {
console.log('Database and tables created!');
// Create a new user
User.create({ name: 'John Doe', age: 25 })
.then(user => {
console.log('User created:', user.toJSON());
// Retrieve all users
User.findAll()
.then(users => {
console.log('All users:', users.map(user => user.toJSON()));
})
.catch(err => console.error('Error retrieving users:', err));
})
.catch(err => console.error('Error creating user:', err));
})
.catch(err => console.error('Error synchronizing database:', err));
In this example, we first create a Sequelize instance by specifying the database connection details, such as the dialect (SQLite) and the storage location for the database file. Then, we define a model for the ‘User’ table with the desired fields and their data types. Calling sequelize.sync() synchronizes the model with the database, creating the necessary table if it doesn’t exist.
We then use the model’s methods to interact with the database. We create a new user using the User.create() method and retrieve all users using the User.findAll() method. The results are logged into the console.
Prisma
Prisma, a modern ORM, can support several SQL databases, MongoDB, and CockroachDB with the help of an additional package. It offers a number of features that make working with databases easier and more effective, including a CLI tool, schemas, a type-safe query builder, migrations, and a GUI for examining your database and schema. You can create your database schema using Prisma‘s schema description language (SDL), and Prisma will then offer a type-safe query builder API based on that model. Database operations can then be written in a way that is more type-safe and developer-friendly. This includes auto-completion, syntax highlighting, and error checking.
Prisma is an ORM (Object-Relational Mapping) tool for Node.js and TypeScript that provides a type-safe and intuitive way to interact with databases. Here’s an example of using Prisma with a PostgreSQL database:
Install the Prisma CLI globally:
npm install -g prisma
Initialize a new Prisma project:
npx prisma init my-prisma-project
Configure your database connection in the prisma/.env file:
DATABASE_URL="postgresql://username:password@localhost:5432/my-database"
Generate Prisma client code based on your database schema:
npx prisma generateExample:
import { PrismaClient } from '@prisma/client';
const prisma = new PrismaClient();
async function main() {
try {
// Create a new user
const newUser = await prisma.user.create({
data: {
name: 'John Doe',
age: 25
}
});
console.log('User created:', newUser);
// Retrieve all users
const allUsers = await prisma.user.findMany();
console.log('All users:', allUsers);
} catch (error) {
console.error('Error:', error);
} finally {
await prisma.$disconnect();
}
}
main().catch(console.error);
In this example, we first import the PrismaClient from @prisma/client and create a new instance of it. We define an async function called main() to contain our Prisma operations.
Inside the main() function, we use the Prisma client methods to interact with the database. We create a new user using the prisma.user.create() method and retrieve all users using the prisma.user.findMany() method. The results are logged to the console.
Make sure to handle any errors and disconnect from the Prisma client using prisma.$disconnect().
Prisma supports various databases such as PostgreSQL, MySQL, SQLite, and SQL Server. You can define your database schema using the Prisma Schema Language and leverage the type-safe queries and mutations provided by Prisma.
TypeORM
TypeORM A free tool for O/R mapping that is compatible with both the Active Record and Data Mapping patterns is TypeORM, which also supports JavaScript and TypeScript. With its help, programmers may be able to create highly effective, high-quality, scalable, loosely coupled, and straightforward-to-maintain programs. It can be used by users to ensure ongoing maintenance for any type of application, including small business apps with just a few tables and huge enterprise applications with multiple databases.
TypeORM is an Object-Relational Mapping (ORM) library for TypeScript and JavaScript that enables you to work with databases using object-oriented programming techniques. Here’s an example of using TypeORM with a PostgreSQL database:
Install TypeORM and the required dependencies:
npm install typeorm pg
Create a new TypeScript file (e.g., index.ts) and configure the connection to your PostgreSQL database:
import { createConnection } from 'typeorm';
async function main() {
try {
const connection = await createConnection({
type: 'postgres',
host: 'localhost',
port: 5432,
username: 'your-username',
password: 'your-password',
database: 'your-database',
synchronize: true,
logging: true,
entities: [__dirname + '/entities/*.ts'],
});
console.log('Connected to the database');
// Perform database operations using TypeORM entities and repositories
// ...
await connection.close();
console.log('Disconnected from the database');
} catch (error) {
console.error('Error:', error);
}
}
main().catch(console.error);
Create a TypeORM entity representing a table in your database (e.g., User.ts):
import { Entity, PrimaryGeneratedColumn, Column } from 'typeorm';
@Entity()
export class User {
@PrimaryGeneratedColumn()
id: number;
@Column()
name: string;
@Column()
age: number;
}
Perform database operations using TypeORM entities and repositories:
// Inside the main() function
const userRepository = connection.getRepository(User);
// Create a new user
const newUser = userRepository.create({ name: 'John Doe', age: 25 });
await userRepository.save(newUser);
// Retrieve all users
const allUsers = await userRepository.find();
console.log('All users:', allUsers);
In this example, we first import the createConnection function from TypeORM to establish a connection with the PostgreSQL database. The connection options include the database credentials and the location of the entity files.
Inside the main() function, we create a connection using createConnection(), perform database operations using TypeORM entities and repositories, and close the connection using connection.close().
We also define a TypeORM entity called User that represents a table in the database. It includes decorators like @Entity() to specify the entity, @PrimaryGeneratedColumn() for the primary key, and @Column() for the table columns.
You can then use the TypeORM repository, obtained through connection.getRepository(), to create, update, retrieve, and delete records in the database.
TypeORM supports various databases like PostgreSQL, MySQL, SQLite, and SQL Server. You can define relationships, perform advanced queries, and benefit from other ORM features provided by TypeORM.
