Django Framework Basics

Django Architecture

• The Django architecture consists of URLs, views, models, and templates
• The framework itself acts as the Controller

Request/Response Cycle

• A web browser requests a page by its URL and the web server passes the HTTP request to Django
• Django runs through its configured URL patterns and stops at the first one that matches the requested URL
• Django executes the view that corresponds to the matched URL pattern
• The view potentially uses data models to retrieve information from the database
• Data models provide the data definition and behaviors and are used to query the database
• The view renders a template (usually HTML) to display the data and returns it with an HTTP response

Models

• Models provide the data definition and behaviors
• Models are used to query the database
• Data models can be customized using model inheritance to create data models for polymorphic content
• Custom model fields can be created to order objects

Views

• Views correspond to the matched URL pattern
• Views potentially use data models to retrieve information from the database
• Authentication views can be implemented for the CMS
• Class-based views and mixins can be used to create a CMS

Templates

• Templates are used to display the data returned by the view
• Templates are usually HTML

URLs

• URLs are used to request a page
• Django runs through its configured URL patterns and stops at the first one that matches the requested URL

Middleware

• Middleware is a hook in the request/response process
• Middleware can be used to create custom middleware in Chapter 17, Going Live

Database

• The Django ORM is a powerful database abstraction API that lets you create, retrieve, update, and delete objects easily
• The ORM maps your models to database tables and provides you with a simple pythonic interface to interact with your database
• The ORM generates SQL queries and maps the results to model objects
• The Django ORM is compatible with MySQL, PostgreSQL, SQLite, Oracle, and MariaDB
• Database routers can be programmed to create custom data routing schemes