Learn how to connect MongoDB with Node.js using Mongoose, define schemas, perform advanced queries, and manage data with ease.

🚀 Getting Started with MongoDB and Mongoose in Node.js

MongoDB is a powerful NoSQL database, and Mongoose is an ODM (Object Data Modeling) library that simplifies working with MongoDB in Node.js.

In this guide, you’ll learn:
✅ Write clean and efficient database logic
✅ Perform queries using filters, sorting, projection, and comparison operators
✅ Define Mongoose schemas and models
✅ How to connect MongoDB with Node.js

 npm i mongoose
 npm i nodemon -D

Create index.js  file and add below code

🧩 Step 1: Connect to MongoDB

const mongoose = require('mongoose');

mongoose.connect('mongodb://127.0.0.1:27017/test')
.then(() => {
  console.log('MongoDB Connected Successfully');
})
.catch((err) => {
   console.log('MongoDB Connection Failed', err);
   process.exit(1);
});

🏗️ Step 2: Define a Schema and Model

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

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

🔍 Step 3: Querying the Database

async function fetchUsers() {
const users = await User.find()
.and([{ isMarried: true }, { age: 28 }])
.select('name age isMarried');

console.log(users);
}

fetchUsers();

🧠 Query Examples
🔹 Find Queries

await User.findOne({ isMarried: false });
await User.find({ isMarried: false }).select('name email sallary');
await User.find({}).select('-name -email');

🔹 Sorting and Limiting

await User.find().sort('sallary');
await User.find().sort('-sallary').limit(2);

🔹 Count Documents

await User.find().countDocuments();

⚖️ Comparison Operators
Operator Usage Example

🔗 Logical Operators

await User.find()
.and([{ isMarried: true }, { age: 28 }])
.select('name age isMarried');

await User.find()
.or([{ age: 30 }, { gender: 'female' }]);

➕ Create a New User (Optional)

async function CreateUser(name, age, email, isMarried, sallary, gender) {
  const user = new User({
    name,
    age,
    email,
    isMarried,
    sallary,
    gender,
  });

  await user.save();
  console.log(`${user.name} Created Successfully`);
}

// Example usage:
// CreateUser('Mike Davis', 40, 'mikedavis@gmail.com', true, 80000, 'male');


📦 Packages Required

Install Mongoose with:

npm install mongoose

🔄 Update a User by ID

You can update a document using either findById and save(), or findByIdAndUpdate():

// Method 1: Find by ID and then update fields
const users = await User.findById('688e453dca90f7632dc68b2e');
users.name = 'John Doe';
await users.save();

// Method 2: Directly update using findByIdAndUpdate

const updatedUser = await User.findByIdAndUpdate(
  '688e453dca90f7632dc68b2e',
  { age: 55 },
  { new: true } // Return the updated document
);

console.log(updatedUser);

🗑️ Delete a User by ID

To remove a document by its ID:

// 🗑️ Delete a user by ID
const users = await User.findByIdAndDelete('688e453dca90f7632dc68b2e');
console.log(users); // Logs the deleted document (or null if not found)

// ❌ Delete a single user by condition
const users = await User.deleteOne({ name: 'John Doe' });
console.log(users); // Logs { acknowledged: true, deletedCount: 1 }

// 🚫 Delete multiple users with age ≥ 30
const users = await User.deleteMany({ age: { $gte: 30 } });
console.log(users); // Logs { acknowledged: true, deletedCount: X }

Notes:

    findByIdAndDelete(id) → Deletes one document by its _id, and returns the deleted document.

    deleteOne(filter) → Deletes the first document that matches the filter. Returns { deletedCount: 1 }.

    deleteMany(filter) → Deletes all documents matching the filter. Returns { deletedCount: N }.


✅ Conclusion

With Mongoose, managing MongoDB becomes much simpler in Node.js. You’ve learned how to:

    Connect and handle MongoDB connections

    Define schemas and models

    Perform filtering, sorting, projection, and complex queries

    Use comparison and logical operators effectively

Let me know if you want a follow-up blog on CRUD operations, 
MongoDB Atlas, or API integration with Express.js!