Learn MongoDB basics, CRUD, querying, data modeling, indexing, and aggregation through hands-on practice, no advanced programming required.

Become a MERN Stack Developer

In this module, you'll dive into MongoDB, the document-oriented, NoSQL database that powers the MERN stack. You’ll explore how its flexible schema design supports rapid iteration and scalability for modern web applications.

Starting with core concepts like databases, collections, and documents, you'll learn to perform CRUD operations efficiently using practical, real-world examples. As you progress, you'll master advanced querying with filters, projections, and operators to extract meaningful insights from your data.

The module also covers key performance techniques, including index optimization and schema design best practices. You'll gain hands-on experience with the aggregation framework for data analysis, and learn to manage your data using import/export tools and backup strategies, skills critical for building and maintaining production-grade MERN applications.

MongoDB Essentials for MERN Stack Development

``` javascript
db.products.find({ name: /eco/i }).limit(1)
```

``` javascript
db.products.findOne({ name: /eco/i })
```

``` javascript
db.products.find({ name: /eco/ }).limit(1)
```

``` javascript
db.products.findOne({ name: /eco/ })
```

Which query will return the first product whose name contains the word "eco" (case-insensitive)?

Which query will return the first product whose name contains the word “eco” (case-insensitive)?

It returns the first 3 users in alphabetical order by name, showing only name and email.

It returns the last 3 users in reverse alphabetical order by name, showing only name and email.

It returns all users, sorted by name, showing only name and email.

It returns the first 3 users in the collection, showing only name and email.

What does this query do?

```javascript
db.users.find({}, { name: 1, email: 1, _id: 0 }).sort({ name: -1 }).limit(3)
```

What does this query do?
<pre><code class="language-javascript">db.users.find({}, { name: 1, email: 1, _id: 0 }).sort({ name: -1 }).limit(3)
</code></pre>

```javascript
db.products.find().sort({ price: 1 }).skip(5).limit(5)
```

```javascript
db.products.find().limit(5).skip(5).sort({ price: 1 })
```

```javascript
db.products.find().sort({ price: 1 }).limit(10).skip(5)
```

```javascript
db.products.find().skip(5).limit(5).sort({ price: 1 })
```

Suppose you want to display the 6th to 10th products sorted by price (lowest to highest). Which query achieves this?

Suppose you want to display the 6th to 10th products sorted by price (lowest to highest). Which query achieves this?

It finds all users whose country is exactly "republic".

It finds all users whose country contains "republic" (case-insensitive).

It finds all users whose address field is missing.

It finds all users whose country starts with "republic".

What does this query do?

```javascript
db.users.find({ "address.country": /republic/i })
```

What does this query do?
<pre><code class="language-javascript">db.users.find({ &quot;address.country&quot;: /republic/i })
</code></pre>

 It will return all fields except `_id` and `name`.

It will throw an error because you cannot mix inclusion and exclusion (except for `_id`). 

 What will happen if you run this query to exclude both `_id` and `name` fields?

```javascript
db.users.find({}, { _id: 0, name: 0 })
```

What will happen if you run this query to exclude both <code>_id</code> and <code>name</code> fields?
<pre><code class="language-javascript">db.users.find({}, { _id: 0, name: 0 })
</code></pre>

```javascript
db.products.find({}, { name: 1, price: 0 })
```

```javascript
db.products.find({}, { name: 1, price: 1 })
```

```javascript
db.products.find({}, { price: 0, _id: 0 })
```

```javascript
db.products.find({}, { name: 0, price: 0 })
```

Which query will throw an error due to incorrect use of projection?

Which query will throw an error due to incorrect use of projection?

Test Your Knowledge. 

Test Your Knowledge.

Test your understanding to help reinforce what you’ve learned so far.

Introduction and Fundamentals

Basic CRUD Operations

Advanced CRUD Operations

Aggregation Framework

Indexing for Performance

Data Modeling and Validation

Importing, Exporting, and Backup

Appendix

Conclusion

Quiz: Basic CRUD Operations