django fundamentals

Tutorial 05 - Django Fundamentals

Why this matters

A new Django project can look intimidating because it creates many files.

You do not need to understand everything before you build.

For Phase 4, learn the small set of concepts you will repeatedly use.

1. What is Django?

Django is a Python web framework.

A framework provides reusable structure and tools for common application tasks.

Django provides systems for:

• URL routing
• request handling
• templates
• forms
• database models
• migrations
• authentication
• administration
• security features

You decide what your application should do. Django provides infrastructure that helps you implement it.

2. Project vs app

A Django project is the overall website/application configuration.

A Django app is a component responsible for an area of functionality.

For example:

Project
├── accounts
├── bookings
└── products

A small MWP may have only one app.

Do not worry if different projects organize apps differently.

3. manage.py

This is the command center for a Django project.

Start the development server:

python manage.py runserver

Create migrations:

python manage.py makemigrations

Apply migrations:

python manage.py migrate

Create an admin user:

python manage.py createsuperuser

4. settings.py

This contains configuration.

You will encounter:

INSTALLED_APPS
DATABASES
STATIC_URL
DEBUG
ALLOWED_HOSTS
SECRET_KEY

Do not memorize every setting.

Instead ask:

What part of Django does this setting configure?

5. urls.py

URL configuration connects browser addresses to Python code.

urlpatterns = [
    path("", home),
    path("about/", about),
]

This creates:

/        → home()
/about/  → about()

6. views.py

A view is Python code that handles a request.

def home(request):
    return render(request, "main/home.html")

A view may:

• retrieve records
• validate input
• create records
• update records
• delete records
• choose a template
• redirect users

Think:

A view is the Python code that decides how to respond to a request.

7. models.py

Models describe application data.

class Booking(models.Model):
    name = models.CharField(max_length=100)
    date = models.DateField()

Django uses this model to work with database records.

8. templates/

Templates contain HTML plus Django template syntax.

<h1>{{ booking.name }}</h1>

They are where server-side data becomes a browser page.

9. admin.py

This configures Django Admin.

from django.contrib import admin
from .models import Booking

admin.site.register(Booking)

Now the model can be managed through /admin/.

10. The complete request flow

For:

/bookings/

a simplified request is:

Browser
   ↓
URL
   ↓
urls.py
   ↓
view
   ↓
model/database
   ↓
template
   ↓
HTML
   ↓
Browser

Not every request uses every step.

For example, a simple static response may not need a database.

11. What not to learn yet

You can postpone:

• advanced class-based views
• middleware internals
• Django REST Framework
• advanced ORM optimization
• custom authentication architecture
• asynchronous internals

Learn advanced features when a real project needs them.

12. Exercise

Open a Phase 4 project and locate:

manage.py
settings.py
urls.py
views.py
models.py
templates/
static/
admin.py

Write one sentence describing each.

13. Using ChatGPT

Ask:

I know Python but am new to Django. Here is my project structure. Explain what each important file does and then trace a request to /bookings/. Do not rewrite anything.

Remember

The architecture matters more than memorizing files:

URL
 ↓
View
 ↓
Model / business logic
 ↓
Template
 ↓
Browser