Interview question

What is the difference between function-based views (FBVs) and class-based views (CBVs) in Django? Django में function-based views (FBVs) और class-based views (CBVs) में क्या अंतर है?

Answer

Aspect	Function-based views	Class-based views
Definition	A plain Python function	A Python class extending View or a generic view
Code reuse	Harder - duplication across similar views	Easier - inheritance and mixins
Readability	Straightforward for simple logic	Can feel 'magic' due to inherited behavior
HTTP method handling	Manual if/else on request.method	Separate methods per HTTP verb (get, post, etc.)

# Function-based view (FBV)
from django.http import HttpResponse
from django.shortcuts import render, get_object_or_404

def book_detail(request, pk):
    book = get_object_or_404(Book, pk=pk)
    if request.method == 'POST':
        # handle form submission
        pass
    return render(request, 'book_detail.html', {'book': book})

# Class-based view (CBV) - equivalent using View
from django.views import View

class BookDetailView(View):
    def get(self, request, pk):
        book = get_object_or_404(Book, pk=pk)
        return render(request, 'book_detail.html', {'book': book})

    def post(self, request, pk):
        # handle form submission - separate method, no if/else needed
        pass

# urls.py - registering each type
from django.urls import path
from . import views

urlpatterns = [
    path('books/<int:pk>/', views.book_detail, name='book-detail-fbv'),
    path('books-cbv/<int:pk>/', views.BookDetailView.as_view(), name='book-detail-cbv'),
]

# Generic CBV - even less code for common patterns
from django.views.generic import DetailView

class BookDetailGeneric(DetailView):
    model = Book
    template_name = 'book_detail.html'
# Automatically handles GET, fetches the object, and renders the template

पहलू	Function-based views	Class-based views
Definition	Plain Python function	View extend करने वाली class
Code reuse	मुश्किल	आसान - inheritance, mixins
HTTP method handling	Manual if/else	हर HTTP verb का अलग method

# Function-based view (FBV)
from django.http import HttpResponse
from django.shortcuts import render, get_object_or_404

def book_detail(request, pk):
    book = get_object_or_404(Book, pk=pk)
    if request.method == 'POST':
        pass
    return render(request, 'book_detail.html', {'book': book})

# Class-based view (CBV)
from django.views import View

class BookDetailView(View):
    def get(self, request, pk):
        book = get_object_or_404(Book, pk=pk)
        return render(request, 'book_detail.html', {'book': book})

    def post(self, request, pk):
        pass

# urls.py
from django.urls import path
from . import views

urlpatterns = [
    path('books/<int:pk>/', views.book_detail, name='book-detail-fbv'),
    path('books-cbv/<int:pk>/', views.BookDetailView.as_view(), name='book-detail-cbv'),
]

# Generic CBV
from django.views.generic import DetailView

class BookDetailGeneric(DetailView):
    model = Book
    template_name = 'book_detail.html'

Was this answer clear?

Subjects

Related questions