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Django 2 by Example

You're reading from   Django 2 by Example Build powerful and reliable Python web applications from scratch

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Product type Paperback
Published in May 2018
Publisher Packt
ISBN-13 9781788472487
Length 526 pages
Edition 1st Edition
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Author (1):
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Antonio Melé Antonio Melé
Author Profile Icon Antonio Melé
Antonio Melé
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Table of Contents (15) Chapters Close

Preface 1. Building a Blog Application FREE CHAPTER 2. Enhancing Your Blog with Advanced Features 3. Extending Your Blog Application 4. Building a Social Website 5. Sharing Content in Your Website 6. Tracking User Actions 7. Building an Online Shop 8. Managing Payments and Orders 9. Extending Your Shop 10. Building an E-Learning Platform 11. Rendering and Caching Content 12. Building an API 13. Going Live 14. Other Books You May Enjoy

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...

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