Node.js – MongoDB Update – Modify Documents in MongoDB with Node.js

Introduction – Why Use Update in MongoDB with Node.js?

In any real-world app, data changes over time. Whether you need to update a user profile, change order status, or modify inventory values, MongoDB’s updateOne() and updateMany() methods allow you to modify documents directly from your Node.js backend.

In this guide, you’ll learn:

• Use updateOne() and updateMany() to modify data
• Use update operators like $set, $inc, and $unset
• Match specific documents using filter conditions
• Handle responses and affected document counts

Setup – MongoDB Connection File (db.js)

const { MongoClient } = require('mongodb');

const url = 'mongodb://127.0.0.1:27017';
const client = new MongoClient(url);
const dbName = 'appDB';

async function getDB() {
  await client.connect();
  console.log(' Connected to MongoDB');
  return client.db(dbName);
}

module.exports = getDB;

Update a Single Document – updateOne()

const getDB = require('./db');

async function updateUser() {
  const db = await getDB();
  const result = await db.collection('users').updateOne(
    { name: 'Alice' }, // filter
    { $set: { email: 'alice2025@example.com' } } // update
  );

  console.log(' Matched:', result.matchedCount);
  console.log(' Modified:', result.modifiedCount);
}

updateUser();

Output:

 Matched: 1  
 Modified: 1

$set updates only the specified fields.

Update Multiple Documents – updateMany()

const result = await db.collection('users').updateMany(
  { role: 'guest' },
  { $set: { status: 'inactive' } }
);
console.log(' Updated users:', result.modifiedCount);

Great for bulk updates based on roles, categories, tags, etc.

Increase a Value – $inc Operator

await db.collection('users').updateOne(
  { name: 'Bob' },
  { $inc: { loginCount: 1 } }
);

Increments loginCount by 1.

Remove a Field – $unset Operator

await db.collection('users').updateOne(
  { name: 'Charlie' },
  { $unset: { temporaryFlag: "" } }
);

Deletes the temporaryFlag field from the document.

Upsert – Insert If Not Exists

await db.collection('users').updateOne(
  { name: 'Diana' },
  { $set: { age: 32 } },
  { upsert: true }
);

If Diana doesn’t exist, MongoDB will create the document.

Best Practices for Updating MongoDB in Node.js

Summary – Recap & Next Steps

Updating data in MongoDB with Node.js is efficient and flexible. From single-field tweaks to full record updates, MongoDB’s syntax is expressive and developer-friendly.

Key Takeaways:

• Use updateOne() for a single match, updateMany() for bulk
• $set updates fields, $inc increments, $unset deletes fields
• Use upsert to insert if the document doesn’t exist
• Always check match/modify counts to verify success

Real-world relevance:
Used in profile updates, admin controls, inventory management, subscription renewals, and background jobs.

FAQs – Updating Documents in MongoDB with Node.js

What’s the difference between updateOne and replaceOne?
updateOne() updates only specified fields; replaceOne() replaces the entire document.

How do I update a nested field in MongoDB?
Use dot notation:

{ $set: { "address.city": "Mumbai" } }

Can I update and insert if not found?
Yes, with { upsert: true } option.

How do I remove a field from all documents?
Use updateMany() with $unset:

{ $unset: { fieldName: "" } }

Can I use dynamic values in updates?
Yes. Just pass JavaScript variables inside the $set or $inc object.