Django Tutorial (Part 2)¶
In the previous part of this tutorial we set up our Django app. Now we’re going to create a new model, and a view. If this is your first time working with these, Django’s models are classes that represent database tables, and Django’s views are functions that handle HTTP requests and return HTTP responses.
1. Creating a New Model¶
In the chapters directory, open the file models.py. This file is where you define your models. Add the following code to the file:
from django.db import models
class Chapter(models.Model):
"""
A model representing a chapter in a digital book.
"""
title = models.CharField(max_length=100)
number = models.IntegerField(unique=True)
Next, run the following commands. The first will generate a migration file, code that tells Django how to create a new table in a database to correspond to this model. The second will run the migration, and create the table in the database.
python manage.py makemigrations
python manage.py migrate
You should see output similar to the following:
Migrations for 'chapters':
chapters/migrations/0001_initial.py
- Create model Chapter
Operations to perform:
Apply all migrations: admin, auth, chapters, contenttypes, sessions
Running migrations:
Applying contenttypes.0001_initial... OK
Applying auth.0001_initial... OK
Applying admin.0001_initial... OK
Applying admin.0002_logentry_remove_auto_add... OK
Applying admin.0003_logentry_add_action_flag_choices... OK
Applying contenttypes.0002_remove_content_type_name... OK
Applying auth.0002_alter_permission_name_max_length... OK
Applying auth.0003_alter_user_email_max_length... OK
Applying auth.0004_alter_user_username_opts... OK
Applying auth.0005_alter_user_last_login_null... OK
Applying auth.0006_require_contenttypes_0002... OK
Applying auth.0007_alter_validators_add_error_messages... OK
Applying auth.0008_alter_user_username_max_length... OK
Applying auth.0009_alter_user_last_name_max_length... OK
Applying auth.0010_alter_group_name_max_length... OK
Applying auth.0011_update_proxy_permissions... OK
Applying auth.0012_alter_user_first_name_max_length... OK
Applying chapters.0001_initial... OK
Applying sessions.0001_initial... OK
2. Creating a New View¶
In Django, views let you define what content gets returned in response to a request. In this part of the tutorial, we’re going to set up a view that renders an HTML page for the requested chapter and populate that page with the corresponding data using the model we previously created.
Start by creating a new file and folder in the chapters directory: templates/chapter.html. Add the following code to the file:
<!DOCTYPE html>
<html>
<head>
<title>{{ chapter.title }}</title>
</head>
<body>
<h1>{{ chapter.title }}</h1>
<p>This is chapter {{ chapter.number }}.</p>
</body>
</html>
In the chapters directory, open the file chapters/views.py. This file is where you define your views. Add the following code to the file:
from django.views.generic import TemplateView
from django.http import HttpResponse
from chapters.models import Chapter
class ChapterView(TemplateView):
"""
Render an HTML page for the requested chapter.
"""
template_name = 'chapter.html'
def get_context_data(self, **kwargs):
context = super().get_context_data(**kwargs)
context['chapter'] = Chapter.objects.get(number=kwargs['number'])
return context
Finally, open the file tutorial/urls.py. This file is where you define the URLs for your views. Ensure the following import for ChapterView is at the top of the file, and that the path for the view is included in the urlpatterns list:
from django.urls import path
from chapters.views import ChapterView
urlpatterns = [
path('chapter/<int:number>/', ChapterView.as_view(), name='chapter'),
]
3. Adding a Chapter¶
To add a chapter to the database, run the following command:
python manage.py shell
This will open a Python shell. Run the following commands to create a new chapter:
from chapters.models import Chapter
Chapter.objects.create(title='Introduction', number=1)
Use Ctrl-D or type in exit() to exit the shell.
Now you should be able to visit http://localhost:8000/chapter/1/ in your web browser and see the chapter page you created.
4. Concluding Part 2¶
This concludes part 2 of this mini Django tutorial. Now you know:
How to create a new model in Django
How to generate and run migrations
How to add views with html templates
How to add a url for your views
How to add data to your database using Django’s shell
If you still want to learn more, Django’s official documentation is a great place to start.
Up next in this series we’ll be building off of the project we’ve begun to learn about how to add Django REST Framework to an existing Django project.
