Connect MongoDB with Node App using MongooseJS (original) (raw)

Last Updated : 21 Jun, 2024

The process of integrating MongoDB, a NoSQL database, with a Node.js application using MongooseJS, a MongoDB object modelling tool designed to work in an asynchronous environment.

Prerequisites:

Steps to connect MongoDB with Node App

Following are the steps to connect MongoDB with a Node.js application using MongooseJS:

**Step 1. Install MongoDB

First, you need to install MongoDB on your system or use a cloud-based MongoDB service like MongoDB Atlas.

**Step 2. Create a Node.js Application

Set up a Node.js application by initializing a new project with npm (Node Package Manager) and installing necessary dependencies.

npm init -y

**Step 3. Install MongooseJS

Use npm to install MongooseJS in your Node.js project. MongooseJS allows you to interact with MongoDB from Node.js using an easy-to-use API.

npm install mongoose

**Folder Structure:

FolderStructure

Folder Strucutre

**Updated Dependencies:

Dependencies

Updated Dependencies

**Step 4. Connect to MongoDB

In your Node.js application, establish a connection to your MongoDB database using MongooseJS. This typically involves specifying the MongoDB connection URI and handling connection events.

JavaScript `

const mongoose = require('mongoose'); // Connect to MongoDB mongoose .connect('mongodb://localhost:27017/mydatabase', { useNewUrlParser: true, useUnifiedTopology: true });

// Handle connection events const db = mongoose.connection; db .on('error', console.error.bind(console, 'MongoDB connection error:')); db.once('open', () => { console.log('Connected to MongoDB'); });

Replace ‘mongodb://localhost:27017/mydatabase’ with the appropriate MongoDB connection URI for your environment.

**Step 5. Define Mongoose Schema

Define Mongoose schema to specify the structure of your MongoDB documents. This includes defining fields, types, validations, and other options.

JavaScript `

const { Schema } = mongoose;

const userSchema = new Schema({ name: String, email: { type: String, required: true, unique: true }, age: Number });

const User = mongoose.model('User', userSchema);

**Step 6. Perform CRUD Operations

With MongooseJS, you can easily perform CRUD (Create, Read, Update, Delete) operations on your MongoDB database using Mongoose models.

JavaScript `

// Create a new user const newUser = new User({ name: 'John', email: 'john@example.com', age: 30 }); newUser.save() .then(() => console.log('User created')) .catch(err => console.error(err));

// Find users User.find({ age: { $gte: 25 } }) .then(users => console.log('Users:', users)) .catch(err => console.error(err));

// Update a user User.updateOne({ _id: 'user_id' }, { age: 35 }) .then(() => console.log('User updated')) .catch(err => console.error(err));

// Delete a user User.deleteOne({ _id: 'user_id' }) .then(() => console.log('User deleted')) .catch(err => console.error(err));

**Step 7. Close MongoDB Connection

Close the MongoDB connection when your Node.js application terminates or shuts down gracefully.

JavaScript `

// Close MongoDB connection mongoose.connection.close(() => { console.log('Disconnected from MongoDB'); });

By following these steps, you can seamlessly connect MongoDB with your Node.js application using MongooseJS, allowing you to store and retrieve data from MongoDB in a structured and efficient manner.

**Example: To demonstrate connecting MongoDB with the Node app using the MongooseJS.

Node `

// index.js file const mongoose = require('mongoose');

// Connect to MongoDB mongoose.connect('database URI', { useNewUrlParser: true, useUnifiedTopology: true });

const db = mongoose.connection; db.on('error', console.error.bind(console, 'MongoDB connection error:')); db.once('open', () => { console.log('Connected to MongoDB');

// Define Mongoose schema
const userSchema = new mongoose.Schema({
    name: String,
    email: { type: String, required: true, unique: true },
    age: Number
});

const User = mongoose.model('User', userSchema);

// Perform CRUD operations

// Create a new user
const newUser = new User({ name: 'John', email: 'john@example.com', age: 30 });
newUser.save()
    .then(() => {
        console.log('User created');

        // Find users with age >= 25
        return User.find({ age: { $gte: 25 } });
    })
    .then(users => {
        console.log('Users:', users);

        // Assuming you have a valid ObjectId for the user you want to update
        const userIdToUpdate = '6123456789abcdef01234567'; // Replace with actual ObjectId
        return User.updateOne({ _id: userIdToUpdate }, { age: 35 });
    })
    .then(() => {
        console.log('User updated');

        // Assuming you have a valid ObjectId for the user you want to delete
        const userIdToDelete = '6123456789abcdef01234567'; // Replace with actual ObjectId
        return User.deleteOne({ _id: userIdToDelete });
    })
    .then(() => {
        console.log('User deleted');

        // Close MongoDB connection
        mongoose.connection.close();
    })
    .catch(err => console.error(err));

});

**Output:

MongoDB-connection

MongoDB connection