🗄️ Node.js – MongoDB: CRUD Operations – Insert, Find, Update & Delete Documents

🧲 Introduction – Perform Core Data Operations with MongoDB & Node.js

CRUD stands for Create, Read, Update, and Delete—the foundational actions for managing application data. When using MongoDB with Node.js, these operations become intuitive, thanks to the flexible JSON-like document structure and the power of the MongoDB driver.

🎯 In this guide, you’ll learn:

• How to insert, find, update, and delete documents in MongoDB using Node.js
• How to use MongoDB methods like insertOne, find, updateOne, and deleteOne
• How to handle real-world data operations with examples and outputs

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📘 Topics Covered

🔹 Topic	📖 Description
➕ Node.js – MongoDB Insert	Add new documents to a MongoDB collection
🔍 Node.js – MongoDB Find	Retrieve one or multiple documents using filters
♻️ Node.js – MongoDB Update	Modify specific fields in existing documents
❌ Node.js – MongoDB Delete	Remove documents from a collection using filters

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➕ Node.js – MongoDB Insert

🔹 insertOne Example

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

async function insertEmployee() {
  const db = client.db('myCompany');
  const result = await db.collection('employees').insertOne({
    name: "Alice",
    role: "HR",
    salary: 50000
  });
  console.log("Document inserted with ID:", result.insertedId);
}

insertEmployee();

🧪 Output:

Document inserted with ID: 665faec7e45acbd2497d12f9

✅ Use insertMany() to insert multiple documents at once.

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🔍 Node.js – MongoDB Find

🔹 Find All Documents

async function findAllEmployees() {
  const db = client.db('myCompany');
  const employees = await db.collection('employees').find().toArray();
  console.log(employees);
}

findAllEmployees();

🧪 Output:

[
  { name: "Alice", role: "HR", salary: 50000 },
  { name: "Bob", role: "Developer", salary: 65000 }
]

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🔹 Find with Filter

async function findByRole() {
  const db = client.db('myCompany');
  const devs = await db.collection('employees').find({ role: "Developer" }).toArray();
  console.log(devs);
}

findByRole();

🧪 Output:

[
  { name: "Bob", role: "Developer", salary: 65000 }
]

✅ You can use query operators like $gt, $lt, $in, $and, etc.

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♻️ Node.js – MongoDB Update

🔹 updateOne Example

async function updateSalary() {
  const db = client.db('myCompany');
  const result = await db.collection('employees').updateOne(
    { name: "Alice" },
    { $set: { salary: 55000 } }
  );
  console.log("Documents matched:", result.matchedCount);
  console.log("Documents modified:", result.modifiedCount);
}

updateSalary();

🧪 Output:

Documents matched: 1
Documents modified: 1

✅ Use $inc, $unset, or $push for numeric or array field operations.

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❌ Node.js – MongoDB Delete

🔹 deleteOne Example

async function deleteEmployee() {
  const db = client.db('myCompany');
  const result = await db.collection('employees').deleteOne({ name: "Alice" });
  console.log("Documents deleted:", result.deletedCount);
}

deleteEmployee();

🧪 Output:

Documents deleted: 1

✅ Use deleteMany() to remove multiple documents matching a condition.

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📌 Summary – Recap & Next Steps

CRUD operations form the backbone of every MongoDB application. Using Node.js, you can perform these operations in a fully asynchronous manner, allowing for real-time apps and scalable backend services.

🔍 Key Takeaways:

• Use insertOne() or insertMany() to add data
• Use find() with filters to query collections
• Use updateOne() or updateMany() for updates
• Use deleteOne() or deleteMany() to remove data

⚙️ Real-World Uses:

• User account management in REST APIs
• Blog or CMS content creation and editing
• Real-time data updates in dashboards
• Transaction logs and cleanup tasks

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❓ Frequently Asked Questions

❓ Can I use async/await with MongoDB operations?
✅ Yes. The MongoDB driver supports Promises—ideal for async functions in Node.js.

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❓ What happens if no document matches in updateOne?
✅ MongoDB returns matchedCount: 0, and no document is modified.

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❓ Is MongoDB case-sensitive for string queries?
✅ Yes, unless you use a case-insensitive regex filter like { name: /alice/i }.

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❓ How do I prevent accidental mass deletions?
✅ Always use specific filters or test queries before applying deleteMany().

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