Django is a Python-based web framework that allows you to quickly create web applications. It has built-in admin interface which makes easy to work with it. It is often called Batteries included framework because it provides built-in facilities for every functionality. Class Based Generic Views are advanced set of Built-in views which are used for implementation of selective view strategies such as Create, Retrieve, Update, Delete. Class based views simplify the use by separating GET, POST requests for a view. They do not replace function-based views, but have certain differences and advantages when compared to function-based views:
- Organization of code related to specific HTTP methods (GET, POST, etc.) can be addressed by separate methods instead of conditional branching.
- Object oriented techniques such as mixins (multiple inheritance) can be used to factor code into reusable components.
This article revolves around complete implementation of Class Based Views in Django (Create, Retrieve, Update, Delete). Let’s discuss what actually CRUD means,
CreateView – create or add new entries in a table in the database.
Retrieve Views – read, retrieve, search, or view existing entries as a list(ListView) or retrieve a particular entry in detail (DetailView)
UpdateView – update or edit existing entries in a table in the database
DeleteView – delete, deactivate, or remove existing entries in a table in the database
FormView – render a form to template and handle data entered by user
Django CRUD (Create, Retrieve, Update, Delete) Class Based Views
Illustration of How to create and use CRUD views using an Example. Consider a project named geeksforgeeks having an app named geeks.
Refer to the following articles to check how to create a project and an app in Django.
After you have a project and an app, let’s create a model of which we will be creating instances through our view. In geeks/models.py,
Python3
from django.db import models
class GeeksModel(models.Model):
title = models.CharField(max_length = 200 )
description = models.TextField()
def __str__( self ):
return self .title
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After creating this model, we need to run two commands in order to create Database for the same.
Python manage.py makemigrations
Python manage.py migrate
Now we will create a Django ModelForm for this model. Refer this article for more on modelform – Django ModelForm – Create form from Models. create a file forms.py in geeks folder,
Python3
from django import forms
from .models import GeeksModel
class GeeksForm(forms.ModelForm):
class Meta:
model = GeeksModel
fields = [
"title" ,
"description" ,
]
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Using Class Based Views
At its core, a class-based view allows you to respond to different HTTP request methods with different class instance methods, instead of with conditionally branching code inside a single view function.
So where the code to handle HTTP GET in a view function would look something like:
Python3
from django.http import HttpResponse
def my_view(request):
if request.method = = 'GET' :
return HttpResponse( 'result' )
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In a class-based view, this would become:
Python3
from django.http import HttpResponse
from django.views import View
class MyView(View):
def get( self , request):
return HttpResponse( 'result' )
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Similarly in urls.py, one needs to use as_view() method to differentiate a class based view from function based view.
Python3
from django.urls import path
from myapp.views import MyView
urlpatterns = [
path( 'about/' , MyView.as_view()),
]
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CreateView
Create View refers to a view (logic) to create an instance of a table in the database. We have already discussed basics of Create View in Create View – Function based Views Django. Class Based Views automatically setup everything from A to Z. One just needs to specify which model to create Create View for and the fields. Then Class based CreateView will automatically try to find a template in app_name/modelname_form.html. In our case it is geeks/templates/geeks/geeksmodel_form.html. Let’s create our class based view. In geeks/views.py,
Python3
from django.views.generic.edit import CreateView
from .models import GeeksModel
class GeeksCreate(CreateView):
model = GeeksModel
fields = [ 'title' , 'description' ]
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Now create a url path to map the view. In geeks/urls.py,
Python3
from django.urls import path
from .views import GeeksCreate
urlpatterns = [
path('', GeeksCreate.as_view() ),
]
|
Create a template in templates/geeks/geeksmodel_form.html,
HTML
< form method = "POST" enctype = "multipart/form-data" >
{% csrf_token %}
{{ form.as_p }}
< input type = "submit" value = "Submit" >
</ form >
|
Let’s check what is there on http://localhost:8000/
To check complete implementation of Class based CreateView, visit Createview – Class Based Views Django.
Retrieve Views
ListView
List View refers to a view (logic) to display multiple instances of a table in the database. We have already discussed basics of List View in List View – Function based Views Django. Class Based Views automatically setup everything from A to Z. One just needs to specify which model to create ListView for, then Class based ListView will automatically try to find a template in app_name/modelname_list.html. In our case it is geeks/templates/geeks/geeksmodel_list.html. Let’s create our class based view. In geeks/views.py,
Python3
from django.views.generic. list import ListView
from .models import GeeksModel
class GeeksList(ListView):
model = GeeksModel
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Now create a url path to map the view. In geeks/urls.py,
Python3
from django.urls import path
from .views import GeeksList
urlpatterns = [
path('', GeeksList.as_view()),
]
|
Create a template in templates/geeks/geeksmodel_list.html,
HTML
< ul >
{% for object in object_list %}
< li >{{ object.title }}</ li >
< li >{{ object.description }}</ li >
< hr />
{% empty %}
< li >No objects yet.</ li >
{% endfor %}
</ ul >
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Let’s check what is there on http://localhost:8000/
To check complete implementation of Class based ListView, visit ListView – Class Based Views Django
DetailView
Detail View refers to a view (logic) to display one instances of a table in the database. We have already discussed basics of Detail View in Detail View – Function based Views Django. Class Based Views automatically setup everything from A to Z. One just needs to specify which model to create DetailView for, then Class based DetailView will automatically try to find a template in app_name/modelname_detail.html. In our case it is geeks/templates/geeks/geeksmodel_detail.html. Let’s create our class based view. In geeks/views.py,
Python3
from django.views.generic.detail import DetailView
from .models import GeeksModel
class GeeksDetailView(DetailView):
model = GeeksModel
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Now create a url path to map the view. In geeks/urls.py,
Python3
from django.urls import path
from .views import GeeksDetailView
urlpatterns = [
path( '<pk>/' , GeeksDetailView.as_view()),
]
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Create a template in templates/geeks/geeksmodel_detail.html,
HTML
< h1 >{{ object.title }}</ h1 >
< p >{{ object.description }}</ p >
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Let’s check what is there on http://localhost:8000/1/
To check complete implementation of Class based DetailView, visit DetailView – Class Based Views Django
UpdateView
UpdateView refers to a view (logic) to update a particular instance of a table from the database with some extra details. It is used to update entries in the database for example, updating an article at geeksforgeeks. We have already discussed basics of Update View in Update View – Function based Views Django. Class Based Views automatically setup everything from A to Z. One just needs to specify which model to create UpdateView for, then Class based UpdateView will automatically try to find a template in app_name/modelname_form.html. In our case it is geeks/templates/geeks/geeksmodel_form.html. Let’s create our class based view. In geeks/views.py,
Python3
from django.views.generic.edit import UpdateView
from .models import GeeksModel
class GeeksUpdateView(UpdateView):
model = GeeksModel
fields = [
"title" ,
"description"
]
success_url = "/"
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Now create a url path to map the view. In geeks/urls.py,
Python3
from django.urls import path
from .views import GeeksUpdateView
urlpatterns = [
path( '<pk>/update' , GeeksUpdateView.as_view()),
]
|
Create a template in templates/geeks/geeksmodel_form.html,
HTML
< form method = "post" >
{% csrf_token %}
{{ form.as_p }}
< input type = "submit" value = "Save" >
</ form >
|
Let’s check what is there on http://localhost:8000/1/update/
To check complete implementation of Class based UpdateView, visit UpdateView – Class Based Views Django.
DeleteView
Delete View refers to a view (logic) to delete a particular instance of a table from the database. It is used to delete entries in the database for example, deleting an article at geeksforgeeks. We have already discussed basics of Delete View in Delete View – Function based Views Django. Class Based Views automatically setup everything from A to Z. One just needs to specify which model to create DeleteView for, then Class based DeleteViewde will automatically try to find a template in app_name/modelname_confirm_delete.html. In our case it is geeks/templates/geeks/geeksmodel_confirm_delete.html. Let’s create our class based view. In geeks/views.py,
Python3
from django.views.generic.edit import DeleteView
from .models import GeeksModel
class GeeksDeleteView(DeleteView):
model = GeeksModel
success_url = "/"
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Now create a url path to map the view. In geeks/urls.py,
Python3
from django.urls import path
from .views import GeeksDeleteView
urlpatterns = [
path( '<pk>/delete/' , GeeksDeleteView.as_view()),
]
|
Create a template in templates/geeks/geeksmodel_confirm_delete.html,
HTML
< form method = "post" >{% csrf_token %}
< p >Are you sure you want to delete "{{ object }}"?</ p >
< input type = "submit" value = "Confirm" >
</ form >
|
Let’s check what is there on http://localhost:8000/1/delete
To check complete implementation of Class based DeleteView, visit DeleteView – Class Based Views Django
FormView
FormView refers to a view (logic) to display and verify a Django Form. For example a form to register users at geeksforgeeks. Class Based Views automatically setup everything from A to Z. One just needs to specify which form to create FormView for and template_name, then Class based FormView will automatically render that form. Let’s create our class based view. In geeks/views.py,
Python3
from django.views.generic.edit import FormView
from .forms import GeeksForm
class GeeksFormView(FormView):
form_class = GeeksForm
template_name = "geeks / geeksmodel_form.html"
success_url = "/thanks/"
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Create a template for this view in geeks/geeksmodel_form.html,
HTML
< form method = "post" >
{% csrf_token %}
{{ form.as_p }}
< input type = "submit" value = "Save" >
</ form >
|
Map a url to this view in geeks/urls.py,
Python3
from django.urls import path
from .views import GeeksFormView
urlpatterns = [
path('', GeeksFormView.as_view()),
]
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Now visit http://127.0.0.1:8000/,
To check complete implementation of Class based FormView, visit FormView – Class Based Views Django
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