Express.js MongoDB CRUD Operations

CRUD operations (Create, Read, Update, and Delete) are the fundamental operations that interact with data in MongoDB. By integrating MongoDB with Express.js, developers can easily manage data in their applications. Below is a guide for performing these operations with Express.js and MongoDB.

 

Key Features of MongoDB CRUD Operations

• Create: Insert new records into the database.
• Read: Retrieve records from the database.
• Update: Modify existing records.
• Delete: Remove records from the database.

 

Setting Up CRUD Operations with MongoDB

Install Dependencies
Make sure express and mongoose are installed.

Example:

npm install express mongoose

MongoDB Connection
Establish a connection to your MongoDB database using Mongoose.

Example:

const mongoose = require('mongoose');

mongoose.connect('mongodb://localhost:27017/mydatabase', { useNewUrlParser: true, useUnifiedTopology: true })
    .then(() => console.log('Connected to MongoDB'))
    .catch(err => console.error('Connection failed', err));

Define a Schema and Model
Create a schema that matches the structure of the data you plan to store in MongoDB.

Example:

const userSchema = new mongoose.Schema({
    name: String,
    email: String,
    age: Number
});

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

CRUD Operations

1. Create (Insert Data)

Add a new document to the MongoDB collection.

Example:

app.post('/add-user', async (req, res) => {
    const user = new User(req.body);
    try {
        await user.save();
        res.send('User added successfully');
    } catch (err) {
        res.status(400).send(err.message);
    }
});

2. Read (Fetch Data)

Retrieve data from the MongoDB collection.

Example:

app.get('/users', async (req, res) => {
    try {
        const users = await User.find();
        res.json(users);
    } catch (err) {
        res.status(500).send(err.message);
    }
});

3. Update (Modify Data)

Update an existing document in the collection.

Example:

app.put('/update-user/:id', async (req, res) => {
    try {
        const user = await User.findByIdAndUpdate(req.params.id, req.body, { new: true });
        res.json(user);
    } catch (err) {
        res.status(400).send(err.message);
    }
});

4. Delete (Remove Data)

Delete a document from the collection.

Example:

app.delete('/delete-user/:id', async (req, res) => {
    try {
        await User.findByIdAndDelete(req.params.id);
        res.send('User deleted successfully');
    } catch (err) {
        res.status(500).send(err.message);
    }
});

 

Complete Example for CRUD Operations

const express = require('express');
const mongoose = require('mongoose');
const bodyParser = require('body-parser');

const app = express();
app.use(bodyParser.json());

// MongoDB connection
mongoose.connect('mongodb://localhost:27017/mydatabase', { useNewUrlParser: true, useUnifiedTopology: true });

// Schema and model
const userSchema = new mongoose.Schema({
    name: String,
    email: String,
    age: Number
});
const User = mongoose.model('User', userSchema);

// Create
app.post('/add-user', async (req, res) => {
    const user = new User(req.body);
    try {
        await user.save();
        res.send('User added successfully');
    } catch (err) {
        res.status(400).send(err.message);
    }
});

// Read
app.get('/users', async (req, res) => {
    try {
        const users = await User.find();
        res.json(users);
    } catch (err) {
        res.status(500).send(err.message);
    }
});

// Update
app.put('/update-user/:id', async (req, res) => {
    try {
        const user = await User.findByIdAndUpdate(req.params.id, req.body, { new: true });
        res.json(user);
    } catch (err) {
        res.status(400).send(err.message);
    }
});

// Delete
app.delete('/delete-user/:id', async (req, res) => {
    try {
        await User.findByIdAndDelete(req.params.id);
        res.send('User deleted successfully');
    } catch (err) {
        res.status(500).send(err.message);
    }
});

// Server
app.listen(3000, () => {
    console.log('Server running on port 3000');
});

 

Summary

Express.js and MongoDB provide an efficient way to manage and manipulate data. With CRUD operations, developers can easily create, read, update, and delete documents in MongoDB, enhancing the functionality of web applications. This integration enables quick data management and seamless API interaction.