Gain insights into MongoDB's core concepts, including queries, CRUD operations, aggregation, and more. Discover how to build applications with hands-on experience and interactive widgets.

mongo.tar.gz

MongoDB is an open-source NoSQL database and stores data in the form of documents. It can be used as an alternative to traditional relational databases. NoSQL databases are schema-less and useful for working with large sets of distributed data. 

In this course, you will learn the core concepts of MongoDB including queries, documents, embedded documents, and operators with advanced features like CRUD operations, bulk write operations, GridFS, indexing, aggregation pipeline, authorization, and more.

You will have plenty of hands-on experience with the help of interactive widgets, and by the end you will have a strong understanding of how to build MongoDB-based applications.

MongoDB: The Complete Guide

**Aggregation** fetches data based on the query, processes it, and returns the computed data. It fetches the data at multiple stages, called **pipelines**. We can use aggregation pipelines to combine results from multiple collections as well. An aggregation pipeline can have more than one stage and every stage performs an operation. 

Below is a list of operations we can perform through an aggregation pipeline stage:

- **`Filter`**: A filter operation is performed on a collection through a provided query.
- **`Join`**: Records from different stages can be added to the primary collection records.
- **`Group`**: The results of the previous stage can be grouped.
- **`Sort`**: The results of the previous stage can be sorted.
- **`Operations`**: Counting and merging records, or arithmetic operations.
- **`Transforming the output`**: We can transform a document or decide which fields to return as a result of the aggregation.

The pipeline stages are executed in order and each stage feeds the input for the next stage. The very first stage receives data from the collection and the last stage returns the result. Middle stages can also return query results on a collection. Moreover, they perform other operations on data from previous stages.

Key points:

- The pipeline stages execute in the order they are provided.
- To run aggregation, it is not necessary to provide all the stages.
- There is no fixed order for a stage but for example, performing `sort` after `limit` could return the wrong results, so we use the stages accordingly.


Learn what an aggregation pipeline is, and practice using operators with the different stages of the aggregation pipelines such as $match and $group.

Introduction to Database and MongoDB

Create Database and Authorization

Performing CRUD Operations on MongoDB - Part 1

Performing CRUD Operations on MongoDB - Part 2

MongoDB Query and Database Performance

Learn Additional MongoDB Topics

Appendix

Aggregation Pipeline - Part 1