Book Image

Django 2 by Example

By : Antonio Melé
Book Image

Django 2 by Example

By: Antonio Melé

Overview of this book

If you want to learn the entire process of developing professional web applications with Django 2, then this book is for you. You will walk through the creation of four professional Django 2 projects, teaching you how to solve common problems and implement best practices. You will learn how to build a blog application, a social image bookmarking website, an online shop and an e-learning platform. The book will teach you how to enhance your applications with AJAX, create RESTful APIs and set up a production environment for your Django 2 projects. The book walks you through the creation of real-world applications, solving common problems, and implementing best practices. By the end of this book, you will have a deep understanding of Django 2 and how to build advanced web applications.
Table of Contents (15 chapters)

Using signals for denormalizing counts

There are some cases when you would like to denormalize your data. Denormalization is making data redundant in a way that it optimizes read performance. You have to be careful about denormalization and only start using it when you really need it. The biggest issue you will find with denormalization is that it's difficult to keep your denormalized data updated.

We will take a look at an example of how to improve our queries by denormalizing counts. The drawback is that we have to keep the redundant data updated. We will denormalize data from our Image model and use Django signals to keep the data updated.

Working with signals

Django comes with a signal dispatcher that allows receiver...