Book Image

MongoDB Fundamentals

By : Amit Phaltankar, Juned Ahsan, Michael Harrison, Liviu Nedov
Book Image

MongoDB Fundamentals

By: Amit Phaltankar, Juned Ahsan, Michael Harrison, Liviu Nedov

Overview of this book

MongoDB is one of the most popular database technologies for handling large collections of data. This book will help MongoDB beginners develop the knowledge and skills to create databases and process data efficiently. Unlike other MongoDB books, MongoDB Fundamentals dives into cloud computing from the very start – showing you how to get started with Atlas in the first chapter. You will discover how to modify existing data, add new data into a database, and handle complex queries by creating aggregation pipelines. As you progress, you'll learn about the MongoDB replication architecture and configure a simple cluster. You will also get to grips with user authentication, as well as techniques for backing up and restoring data. Finally, you'll perform data visualization using MongoDB Charts. You will work on realistic projects that are presented as bitesize exercises and activities, allowing you to challenge yourself in an enjoyable and attainable way. Many of these mini-projects are based around a movie database case study, while the last chapter acts as a final project where you will use MongoDB to solve a real-world problem based on a bike-sharing app. By the end of this book, you'll have the skills and confidence to process large volumes of data and tackle your own projects using MongoDB.
Table of Contents (15 chapters)
Preface

Logical Operators

So far, we have learned about various operators used for writing comparison-based queries. The queries we have written so far had only one criterion at a time. But in practical scenarios, you may need to write more complex queries. MongoDB provides four logical operators to help you build logical combinations of multiple criteria in the same query. Let's have a look at them.

$and operator

Using the $and operator, you can have any number of conditions wrapped in an array and the operator will return only the documents that satisfy all the conditions. When a document fails a condition check, the next conditions are skipped. That is why the operator is called a short-circuit operator. For example, say you want to determine the count of unrated movies that were released in 2008. This query must have two conditions:

  • The field rated should have a value of UNRATED
  • The field year must be equal to 2008

In the document format, both queries can...