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

# `$addToSet` operator

The **`$addToSet`** operator is similar to the `$push` operator, except it only adds the value if it doesn’t already exist.

# ` operator

The **`$`** operator is used to update the value of the first element of an array field returned from the `filter query`.

Below is an example of updating the first value of `tags` from `new` to `old`.


# `＄addToSet` operator

The **`＄addToSet`** operator is similar to the `＄push` operator, except it only adds the value if it doesn’t already exist.

# ` operator

The **`＄`** operator is used to update the value of the first element of an array field returned from the `filter query`.

Below is an example of updating the first value of `tags` from `new` to `old`.


db.tasks.updateOne({
  name: "Learn MongoDB Topic 1",
  tags: "new",
}, {
  $set: {
     "tags.$": "old",
  }
});

> **Note:**  The field should be an array. Otherwise, the command throws an error.

Below is another example using the `＄inc` operator to update the first return value of an array field. In this example, we also use the `＄gt` operator to filter array values.

Learn and practice the addToSet, [], and each when updating documents.

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

Update Documents - Part 3

`$addToSet` operator

`$` operator

Update Documents - Part 3

$addToSet operator

$ operator

`$addToSet` operator

`$` operator