10 Django Secrets No One Talks About (But You Should Know!)
Django is a powerful framework, but there are hidden features and best practices that many developers overlook. These “secrets” can…
Django is a powerful framework, but there are hidden features and best practices that many developers overlook. These “secrets” can supercharge your development.
In this article, we’ll uncover 10 Django secrets that no one talks about — but you definitely should know! 🚀
1. You Can Use Query Expressions for Complex Queries
Django ORM allows complex queries using F and Q objects, reducing database hits and improving efficiency.
Example: Updating a Field Dynamically
Instead of doing this, like updating stock value (bad practice):
product = Product.objects.get(id=1)
product.stock = product.stock - 1
product.save()Instead of this use F() expression to update the stock (efficient way):
from django.db.models import F
Product.objects.filter(id=1).update(stock=F("stock") - 1)This will reduce multiple database queries, and executes the operation directly in SQL, making it faster.
2. select_related and prefetch_related Can Speed Up Queries
Django ORM performs lazy loading by default, leading to N+1 query problems.
Use select_related and prefetch_related to optimize queries.
Example: Avoiding N+1 Queries
Without optimization, it will lead to N + 1 query problem (bad):
orders = Order.objects.all()
for order in orders:
print(order.customer.name) # This makes an extra query for each order!With select_related you can optimized for ForeignKey relationships:
orders = Order.objects.select_related("customer").all()With prefetch_related you can optimized for ManyToMany relationships:
orders = Order.objects.prefetch_related("products").all()This will Reduces the number of queries and boosts performance by preloading related objects.
3. You Can Use Database Indexing to Improve Performance
By default, Django doesn’t create indexes for every field. You can manually add indexes to speed up queries.
Example: Adding Indexes to a Model
from django.db import models
class User(models.Model):
email = models.EmailField(unique=True, db_index=True) # Indexed!
username = models.CharField(max_length=150, db_index=True) # Indexed!This will Speeds up query lookups and Improves database efficiency.
4. exists() is Faster than Counting Objects
Instead of using .count() to check if records exist, use .exists().
Example: Checking for Records
This will scans the entire table, which is slow :
if User.objects.filter(email="test@example.com").count() > 0:
print("User exists")This will stops searching as soon as it finds a match
if User.objects.filter(email="test@example.com").exists():
print("User exists")5. You Can Override get_queryset() in Django Views
Instead of filtering inside views, override get_queryset() in Django’s ListView.
Example: Optimizing Querysets in Class-Based Views
from django.views.generic import ListView
from .models import Order
class OrderListView(ListView):
model = Order
def get_queryset(self):
return Order.objects.filter(status="completed").select_related("customer")This will Keeps views cleaner and Improves query performance.
6. LOADING STATIC FILES FROM THE DATABASE
Did you know Django can serve static files from the database? This is useful when you want dynamic themes or user-uploaded CSS files.
Example: Storing Static Files in a Model
from django.db import models
class Theme(models.Model):
name = models.CharField(max_length=100)
css_file = models.TextField() # Stores CSS contentThen, you can load it dynamically in your templates:
<style>{{ theme.css_file|safe }}</style>It is useful for custom themes and dynamic styling.
7. You Can Store Django Sessions in the Database
By default, Django stores sessions in cookies, but you can store them in the database for better scalability.
Enable Database Session Storage
# settings.py
SESSION_ENGINE = "django.contrib.sessions.backends.db"Run migrations:
python manage.py migrate sessionsThis is more secure than storing sessions in cookies and Supports larger session data.
8. Django Has Built-in Support for Database Constraints
Django automatically enforces database constraints, but you can define them explicitly.
Example: Enforcing Unique Constraints
class Subscription(models.Model):
user = models.ForeignKey(User, on_delete=models.CASCADE)
plan = models.CharField(max_length=100)
class Meta:
constraints = [
models.UniqueConstraint(fields=["user", "plan"], name="unique_subscription")
]This ensures data consistency at the database level.
9. You Can Add Custom Permissions to Models
Django has built-in permissions (add, change, delete), but you can add custom ones.
Example: Adding Custom Permissions
class Order(models.Model):
user = models.ForeignKey(User, on_delete=models.CASCADE)
class Meta:
permissions = [
("can_cancel_order", "Can cancel an order"),
("can_process_refund", "Can process refunds"),
]Now, you can check permissions in views:
if request.user.has_perm("app.can_cancel_order"):
print("User can cancel orders!")This will adds fine-grained access control to your app.
10. Django Has Built-in Support for Full-Text Search
If you need search functionality, Django supports full-text search in PostgreSQL.
Example: Enabling Full-Text Search
from django.contrib.postgres.search import SearchVector
from .models import BlogPost
posts = BlogPost.objects.annotate(
search=SearchVector("title", "content")
).filter(search="django")This is faster than icontains for large datasets and supports ranking and relevance-based search.
Final Thoughts
These Django secrets can help you build better, faster, and more secure applications.
Which Django secret did you find the most useful? Let me know in the comments! 🚀
