MongoDB

Try a NoSQL approach with MongoDB: schemaless documents, flexible queries, aggregation pipelines, and managed hosting on Atlas.

MongoDBNoSQLAtlasaggregation

Duration

⏱ About 2.5 hours

Level

📊 Intermediate

Prerequisite

🎯 db-01

OUTCOME

A working Node app talking to a MongoDB Atlas cluster

What you'll learn

1Sign up for MongoDB Atlas (free tier)
2Connect from Node with the official driver
3Query with find, findOne, insertOne, updateOne, deleteOne
4Use the aggregation pipeline for grouping and joining

1. Document Model

json

// A single document
{
  "_id": "658a...",
  "name": "Alice",
  "email": "alice@example.com",
  "tags": ["admin", "editor"],
  "profile": { "city": "Seoul" }
}

No fixed schema — but applying one in code (with Mongoose, Zod, etc.) saves you from data drift.

2. Connect from Node

bash

npm install mongodb

javascript

import { MongoClient } from "mongodb";

const client = new MongoClient(process.env.MONGO_URL);
await client.connect();
const db = client.db("myapp");
const users = db.collection("users");

3. CRUD

javascript

// Insert
await users.insertOne({ name: "Alice", email: "a@example.com" });

// Read
const one = await users.findOne({ email: "a@example.com" });
const many = await users.find({ "profile.city": "Seoul" }).limit(10).toArray();

// Update
await users.updateOne({ _id: id }, { $set: { name: "Alicia" } });
await users.updateMany({ active: true }, { $inc: { loginCount: 1 } });

// Delete
await users.deleteOne({ _id: id });

4. Aggregation Pipeline

javascript

const result = await db.collection("orders").aggregate([
  { $match: { status: "paid" } },
  { $group: { _id: "$customerId", total: { $sum: "$amount" } } },
  { $sort:  { total: -1 } },
  { $limit: 10 },
]).toArray();

Pipelines feed documents through stages — match, group, sort, project, lookup (the NoSQL equivalent of JOIN).

Example code / lecture materials

All lecture materials and example code are openly available on GitHub.

View on GitHub ↗