Introduction

MongoDB is a NoSQL database that offers scalability, flexibility, and high performance for modern applications. Unlike relational databases, MongoDB stores data in JSON-like documents, making it a great choice for dynamic applications.

In this tutorial, we will explore:

✅ Setting up MongoDB with Flask
✅ Using PyMongo to interact with MongoDB
✅ Performing CRUD operations (Create, Read, Update, Delete)
✅ Building a simple API with Flask and MongoDB

Step 1: Install MongoDB and PyMongo

Install MongoDB

MongoDB must be installed and running. For local development, you can:

🔹 Install MongoDB from MongoDB’s official site
🔹 Use Docker:

docker run -d -p 27017:27017 --name mongodb mongo:latest

Install PyMongo

PyMongo is the official Python driver for MongoDB:

pip install flask pymongo

Step 2: Configure Flask and MongoDB

Create a Flask application and configure MongoDB connection:

from flask import Flask, request, jsonify
from flask_pymongo import PyMongo

app = Flask(__name__)
app.config["MONGO_URI"] = "mongodb://localhost:27017/mydatabase"
mongo = PyMongo(app)

🔹 MONGO_URI specifies the database connection
🔹 PyMongo(app) initializes MongoDB with Flask

Step 3: Define a Data Model

MongoDB does not enforce schemas, but we can define a structured document format in our application.

For example, a user document might look like:

{
"name": "John Doe",
"email": "john@example.com",
"age": 30
}

Step 4: Implement CRUD Operations

Create (Insert a New User)

@app.route("/users", methods=["POST"])
def create_user():
data = request.json
user_id = mongo.db.users.insert_one(data).inserted_id
return jsonify({"message": "User added", "id": str(user_id)})

📌 insert_one(data) adds a new document to the collection

Read (Get All Users)

@app.route("/users", methods=["GET"])
def get_users():
users = list(mongo.db.users.find({}, {"_id": 0}))
return jsonify(users)

📌 find({}, {"_id": 0}) fetches all users while excluding _id

Update (Modify an Existing User)

@app.route("/users/<email>", methods=["PUT"])
def update_user(email):
data = request.json
result = mongo.db.users.update_one({"email": email}, {"$set": data})
return jsonify({"message": "User updated", "matched": result.matched_count})

📌 update_one() modifies documents based on email

Delete (Remove a User)

@app.route("/users/<email>", methods=["DELETE"])
def delete_user(email):
result = mongo.db.users.delete_one({"email": email})
return jsonify({"message": "User deleted", "deleted": result.deleted_count})

📌 delete_one() removes a document matching the query

Step 5: Indexing and Performance Optimization

For faster queries, create indexes:

mongo.db.users.create_index("email", unique=True)

🔹 Indexes improve search performance
🔹 unique=True prevents duplicate emails

Step 6: Running the Flask App

Start the Flask server:

flask run --host=0.0.0.0 --port=5000

Now, test the API using Postman or cURL.

Conclusion

🔹 Flask + MongoDB = Scalable NoSQL Web Apps
🔹 PyMongo makes database interactions easy
🔹 CRUD operations help manage data efficiently

By following this guide, you can integrate MongoDB with Flask and build powerful NoSQL applications! 🚀