Pythonv6.0INTERMEDIATEDjango
Django cheat sheet covering models, views, templates, ORM queries, URL routing, forms, and deployment patterns with code examples.
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Sign inSetup & Project Structure
Initialize Django projects and understand the structure
Project Setup
Create and configure a Django project
python
pip install django
django-admin startproject myproject
cd myproject
python manage.py startapp myapp
python manage.py runserver💡 Always use virtual environments for Django projects
⚡ django-admin for project, manage.py for apps
📌 Keep sensitive settings in .env file
🟢 Run migrations after creating models
Models & ORM
Define database models and work with Django ORM
Model Definition
Create Django models with fields and relationships
python
from django.db import models
class Product(models.Model):
name = models.CharField(max_length=200)
price = models.DecimalField(max_digits=10, decimal_places=2)
created = models.DateTimeField(auto_now_add=True)
def __str__(self):
return self.name💡 Use related_name for clear reverse relationships
📌 Always define __str__ for readable admin
⚡ Add db_index=True for frequently queried fields
🟢 Use Meta class for ordering and indexes
QuerySet Operations
Database queries with Django ORM
python
# Basic queries
Product.objects.all()
Product.objects.filter(price__lt=100)
Product.objects.get(id=1)
Product.objects.exclude(stock=0)
# Aggregation
from django.db.models import Count, Avg
Product.objects.aggregate(Avg('price'))💡 Use select_related for ForeignKeys
⚡ F expressions avoid race conditions
📌 bulk_create is faster for many records
🔍 Q objects enable complex queries
Views & URLs
Handle requests with views and URL routing
Views
Function and class-based views
python
from django.shortcuts import render, get_object_or_404
def product_list(request):
products = Product.objects.all()
return render(request, 'products/list.html', {'products': products})
# Class-based view
from django.views.generic import ListView
class ProductListView(ListView):
model = Product
template_name = 'products/list.html'💡 Use CBV for standard CRUD operations
📌 LoginRequiredMixin for auth protection
⚡ Override get_queryset() for filtering
🟢 Function views are simpler for custom logic
URL Configuration
URL patterns and routing
python
from django.urls import path
from . import views
urlpatterns = [
path('', views.index, name='index'),
path('products/', views.ProductListView.as_view(), name='product_list'),
path('products/<slug:slug>/', views.product_detail, name='product_detail'),
]💡 Use app_name for URL namespacing
📌 Path converters: str, int, slug, uuid
⚡ Include trailing slashes consistently
🟢 Use reverse() for maintainable URLs
Templates
Django template system
Template Syntax
Django template language basics
html
<!-- Variables -->
{{ product.name }}
{{ product.price|floatformat:2 }}
<!-- Tags -->
{% if product.in_stock %}
<p>Available</p>
{% endif %}
{% for product in products %}
{{ product.name }}
{% endfor %}💡 Use |default filter for None values
📌 {% empty %} handles empty loops
⚡ Template inheritance with extends
🟢 Always {% load static %} for static files
Forms
Handle user input with Django forms
Forms and ModelForms
Create and validate forms
python
from django import forms
from .models import Product
class ProductForm(forms.ModelForm):
class Meta:
model = Product
fields = ['name', 'price', 'description']💡 clean_<field>() for field validation
📌 clean() for cross-field validation
⚡ Use widgets to customize HTML
🟢 commit=False to modify before saving
Admin Interface
Customize Django admin
Admin Configuration
Register and customize admin
python
from django.contrib import admin
from .models import Product
@admin.register(Product)
class ProductAdmin(admin.ModelAdmin):
list_display = ['name', 'price', 'stock', 'created']
list_filter = ['status', 'created']
search_fields = ['name', 'description']💡 Use list_editable for inline editing
📌 prepopulated_fields for slug generation
⚡ Custom actions for bulk operations
🟢 format_html for safe HTML in admin
Authentication
User authentication and permissions
User Authentication
Login, logout, and permissions
python
from django.contrib.auth import login, authenticate, logout
from django.contrib.auth.decorators import login_required
@login_required
def profile(request):
return render(request, 'profile.html')💡 Use Django's built-in auth views
🔐 Always hash passwords automatically
📌 LoginRequiredMixin for CBV protection
⚡ @login_required decorator for FBV
Testing
Write tests for Django apps
Django Testing
Unit and integration tests
python
from django.test import TestCase, Client
from .models import Product
class ProductTestCase(TestCase):
def setUp(self):
Product.objects.create(name="Test", price=10)
def test_product_creation(self):
product = Product.objects.get(name="Test")
self.assertEqual(product.price, 10)💡 Use setUp() for test data
📌 Test both success and failure cases
⚡ Use --parallel for faster tests
🟢 Client() simulates requests
Deployment
Deploy Django to production
Production Deployment
Deploy with gunicorn and nginx
python
# Collect static files
python manage.py collectstatic
# Gunicorn
gunicorn myproject.wsgi:application --bind 0.0.0.0:8000
# Docker
FROM python:3.11
WORKDIR /app
COPY . .
RUN pip install -r requirements.txt
CMD ["gunicorn", "myproject.wsgi", "--bind", "0.0.0.0:8000"]💡 Use environment variables for secrets
📌 Always collectstatic before deploy
⚡ Use CDN for static files
🟢 Enable caching with Redis