Basic CRUD Operations in MongoDB (Create, Read, Update, Delete)

CRUD operations form the backbone of any database-driven application. In MongoDB, CRUD stands for Create, Read, Update, and Delete—the four fundamental actions you perform on data.

If you’re new to MongoDB, mastering these operations will give you the confidence to build real-world applications. This guide explains MongoDB CRUD operations in a clear, beginner-friendly way, with practical examples.

What Are CRUD Operations?

Operation	Purpose
Create	Insert new data
Read	Retrieve existing data
Update	Modify existing data
Delete	Remove data

In MongoDB, CRUD operations are performed on collections, and each record is stored as a document.

Getting Started: Example Collection

Let’s assume we have a users collection in a database called appDB.

Sample document:


{
  "name": "Rahul",
  "email": "rahul@example.com",
  "age": 28,
  "isActive": true
}

1. Create: Inserting Documents in MongoDB

Insert a Single Document


db.users.insertOne({
  name: "Rahul",
  email: "rahul@example.com",
  age: 28,
  isActive: true
});

MongoDB automatically adds a unique _id field.

Insert Multiple Documents


db.users.insertMany([
  { name: "Anita", age: 25, isActive: true },
  { name: "Rohit", age: 30, isActive: false }
]);

2. Read: Querying Documents in MongoDB

Find All Documents


db.users.find();

Find with Conditions


db.users.find({ isActive: true });

Find One Document


db.users.findOne({ name: "Rahul" });

Projection (Select Specific Fields)


db.users.find(
  { isActive: true },
  { name: 1, email: 1, _id: 0 }
);

3. Update: Modifying Documents in MongoDB

Update One Document


db.users.updateOne(
  { name: "Rahul" },
  { $set: { age: 29 } }
);

Update Multiple Documents


db.users.updateMany(
  { isActive: false },
  { $set: { isActive: true } }
);

Replace a Document


db.users.replaceOne(
  { name: "Anita" },
  { name: "Anita", age: 26, isActive: true }
);

⚠️ replaceOne removes fields not included in the new document.

4. Delete: Removing Documents in MongoDB

Delete One Document


db.users.deleteOne({ name: "Rohit" });

Delete Multiple Documents


db.users.deleteMany({ isActive: false });

Delete All Documents (Use with Caution)


db.users.deleteMany({});

5. Understanding Filters and Operators

MongoDB supports powerful query operators.

Comparison Operators


db.users.find({ age: { $gt: 25 } });

$gt → greater than
$lt → less than
$gte, $lte, $ne

Logical Operators


db.users.find({
  $and: [
    { isActive: true },
    { age: { $gte: 25 } }
  ]
});

6. Common CRUD Mistakes Beginners Make

Forgetting filters in update or delete operations
Using updateMany accidentally
Not using $set (overwriting documents)
Deleting data without backup

👉 Always double-check your query before executing it.

7. CRUD Operations Using MongoDB Compass

MongoDB Compass allows you to:

Insert documents visually
Edit fields inline
Apply filters without code
Delete documents safely

This is great for beginners and debugging.

8. Best Practices for CRUD Operations

Use indexes for frequently queried fields
Validate data before inserting
Avoid large documents
Test update and delete queries carefully
Backup important data regularly

Final Thoughts

CRUD operations are the foundation of MongoDB. Once you master Create, Read, Update, and Delete, you’re ready to move on to advanced topics like indexing, aggregation, and schema design.

MongoDB’s simple and flexible CRUD syntax makes it beginner-friendly and powerful at the same time.

The Coding Dev