Class Based Generic Views Django (Create, Retrieve, Update, Delete)

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

Illustration of How to create and use CRUD views using an Example. Consider a project named mcatutorials having an app named Mcatutorials.

Refer to the following articles to check how to create a project and an app in Django.

• How to Create a Basic Project using MVT in Django?
• How to Create 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 Mcatutorials/models.py,

# import the standard Django Model 
# from built-in library 
from django.db import models 
   
# declare a new model with a name "McatutorialsModel" 
class McatutorialsModel(models.Model): 
  
    # fields of the model 
    title = models.CharField(max_length = 200) 
    description = models.TextField() 
  
    # renames the instances of the model 
    # with their title name 
    def __str__(self): 
        return self.title 

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 Mcatutorials folder,

from django import forms 
from .models import McatutorialsModel 
  
  
# creating a form 
class McatutorialsForm(forms.ModelForm): 
  
    # create meta class 
    class Meta: 
        # specify model to be used 
        model = McatutorialsModel 
  
        # specify fields to be used 
        fields = [ 
            "title", 
            "description", 
        ]

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

from django.http import HttpResponse 
  
def my_view(request): 
    if request.method == 'GET': 
        # < view logic> 
        return HttpResponse('result')

In a class-based view, this would become:

from django.http import HttpResponse 
from django.views import View 
  
class MyView(View): 
    def get(self, request): 
        # < view logic> 
        return HttpResponse('result') 

Similarly in urls.py, one needs to use as_view() method to diffrentiate a class based view from function based view.

# urls.py 
from django.urls import path 
from myapp.views import MyView 
  
urlpatterns = [ 
  
    path('about/', MyView.as_view()), 
  
] 

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 Mcatutorials/templates/Mcatutorials/Mcatutorialsmodel_form.html. Let’s create our class based view. In Mcatutorials/views.py,

from django.views.generic.edit import CreateView 
from .models import McatutorialsModel 
  
class McatutorialsCreate(CreateView): 
  
    # specify the model for create view 
    model = McatutorialsModel 
  
    # specify the fields to be displayed 
  
    fields = ['title', 'description'] 

Now create a url path to map the view. In Mcatutorials/urls.py,

from django.urls import path 
  
# importing views from views..py 
from .views import McatutorialsCreate 
urlpatterns = [ 
    path('', McatutorialsCreate.as_view() ), 
]

Create a template in templates/Mcatutorials/Mcatutorialsmodel_form.html,

< form method="POST" enctype="multipart/form-data"> 
  
    < !-- Security token -->
    {% csrf_token %} 
  
    < !-- Using the formset -->
    {{ 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.

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 Mcatutorials/templates/Mcatutorials/Mcatutorialsmodel_list.html. Let’s create our class based view. In Mcatutorials/views.py,

from django.views.generic.list import ListView 
from .models import McatutorialsModel 
  
class McatutorialsList(ListView): 
  
    # specify the model for list view 
    model = McatutorialsModel 

Now create a url path to map the view. In Mcatutorials/urls.py,

from django.urls import path 
  
# importing views from views..py 
from .views import McatutorialsList 
urlpatterns = [ 
    path('', McatutorialsList.as_view()), 
]

Create a template in templates/Mcatutorials/Mcatutorialsmodel_list.html,

< ul> 
    < !-- Iterate over object_list -->
    {% for object in object_list %} 
    < !-- Display Objects -->
    < li>{{ object.title }}< /li> 
    < li>{{ object.description }}< /li> 
  
    < hr/> 
    < !-- If objet_list is empty  -->
    {% empty %} 
    < li>No objects yet.< /li> 
    {% endfor %} 
< /ul>

Let’s check what is there on http://localhost:8000/

To check complete implementation of Class based ListView, visit ListView – Class Based Views Django

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 Mcatutorials/templates/Mcatutorials/Mcatutorialsmodel_detail.html. Let’s create our class based view. In Mcatutorials/views.py,

from django.views.generic.detail import DetailView 
  
from .models import McatutorialsModel 
  
class McatutorialsDetailView(DetailView): 
    # specify the model to use 
    model = McatutorialsModel

Now create a url path to map the view. In Mcatutorials/urls.py,

from django.urls import path 
  
# importing views from views..py 
from .views import McatutorialsDetailView 
urlpatterns = [ 
    # < pk> is identification for id field, 
    # slug can also be used 
    path('< pk>/', McatutorialsDetailView.as_view()), 
]

Create a template in templates/Mcatutorials/Mcatutorialsmodel_detail.html,

< h1>{{ object.title }}< /h1> 
< p>{{ object.description }}< /p>

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 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 enteries in the database for example, updating an article at mcatutorials. 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 Mcatutorials/templates/Mcatutorials/Mcatutorialsmodel_form.html. Let’s create our class based view. In Mcatutorials/views.py,

# import generic UpdateView 
from django.views.generic.edit import UpdateView 
  
# Relative import of McatutorialsModel 
from .models import McatutorialsModel 
  
class McatutorialsUpdateView(UpdateView): 
    # specify the model you want to use 
    model = McatutorialsModel 
  
    # specify the fields 
    fields = [ 
        "title", 
        "description"
    ] 
  
    # can specify success url 
    # url to redirect after successfully 
    # updating details 
    success_url ="/"

Now create a url path to map the view. In Mcatutorials/urls.py,

from django.urls import path 
  
# importing views from views..py 
from .views import McatutorialsUpdateView 
urlpatterns = [ 
    # < pk> is identification for id field, 
    # < slug> can also be used 
    path('< pk>/update', McatutorialsUpdateView.as_view()), 
]

Create a template in templates/Mcatutorials/Mcatutorialsmodel_form.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.

Delete View refers to a view (logic) to delete a particular instance of a table from the database. It is used to delete enteries in the database for example, deleting an article at mcatutorials. 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 Mcatutorials/templates/Mcatutorials/Mcatutorialsmodel_confirm_delete.html. Let’s create our class based view. In Mcatutorials/views.py,

# import generic UpdateView 
from django.views.generic.edit import DeleteView 
  
# Relative import of McatutorialsModel 
from .models import McatutorialsModel 
  
class McatutorialsDeleteView(DeleteView): 
    # specify the model you want to use 
    model = McatutorialsModel 
      
    # can specify success url 
    # url to redirect after successfully 
    # deleting object 
    success_url ="/"

Now create a url path to map the view. In Mcatutorials/urls.py,

from django.urls import path 
  
# importing views from views..py 
from .views import McatutorialsDeleteView 
urlpatterns = [ 
    # < pk> is identification for id field, 
    # slug can also be used 
    path('< pk>/delete/', McatutorialsDeleteView.as_view()), 
]

Create a template in templates/Mcatutorials/Mcatutorialsmodel_confirm_delete.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 refers to a view (logic) to display and verify a Django Form. For example a form to register users at mcatutorials. 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 Mcatutorials/views.py,

# import generic FormView 
from django.views.generic.edit import FormView 
  
# Relative import of McatutorialsForm 
from .forms import McatutorialsForm 
  
class McatutorialsFormView(FormView): 
    # specify the Form you want to use 
    form_class = McatutorialsForm 
      
    # sepcify name of template 
    template_name = "Mcatutorials / Mcatutorialsmodel_form.html"
  
    # can specify success url 
    # url to redirect after successfully 
    # updating details 
    success_url ="/thanks/"

Create a template for this view in Mcatutorials/Mcatutorialsmodel_form.html,

< form method="post"> 
    {% csrf_token %} 
    {{ form.as_p }} 
    < input type="submit" value="Save"> 
< /form> 

Map a url to this view in Mcatutorials/urls.py,

from django.urls import path 
  
# importing views from views..py 
from .views import McatutorialsFormView 
urlpatterns = [ 
    path('', McatutorialsFormView.as_view()), 
]

Now visit http://127.0.0.1:8000/,

To check complete implementation of Class based FormView, visit FormView – Class Based Views Django