In Chapter 3, we covered the fundamentals of building dynamic Web sites with Django: setting up views and URLconfs. As I explained, a view is responsible for doing some arbitrary logic, and then returning a response. In the example, our arbitrary logic was to calculate the current date and time.
In modern Web applications, the arbitrary logic often involves interacting with a database. Behind the scenes, a database-driven Web site connects to a database server, retrieves some data out of it, and displays that data, nicely formatted, on a Web page. Or, similarly, the site could provide functionality that lets site visitors populate the database on their own.
Many complex Web sites provide some combination of the two. Amazon.com, for instance, is a great example of a database-driven site. Each product page is essentially a query into Amazon’s product database formatted as HTML, and when you post a customer review, it gets inserted into the database of reviews.
Django is well suited for making database-driven Web sites, as it comes with easy yet powerful ways of performing database queries using Python. This chapter explains that functionality: Django’s database layer.
While it’s not strictly necessary to know basic database theory and SQL in order to use Django’s database layer, it’s highly recommended. An introduction to those concepts is beyond the scope of this book, but keep reading even if you’re a database newbie. You’ll probably be able to follow along and grasp concepts based on the context.
