Django Function Based Views

Function-Based Views (FBVs) in Django are Python functions used to handle web requests and send back web responses.

• Each FBV is linked to a specific URL and controls what happens when that URL is visited.
• Every view function receives an HttpRequest object from the browser.
• The view returns an HttpResponse, which can be HTML, a redirect, or an error page.
• FBVs provide a clear and straightforward way to define application logic.

Function-Based List View

Consider a project named ‘geeksforgeeks’ having an app named ‘geeks’. After setting up the project and app, let's create a function-based List View to display instances of a model. First, define the model whose instances will be displayed through this view.

In geeks/models.py:

from django.db import models
 
# declare a new model with a name "GeeksModel"
class GeeksModel(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 listed below in order to create Database for the same:

Python manage.py makemigrations
Python manage.py migrate

Now, create instances of this model using the Django shell by running the following command in the terminal:

Python manage.py shell

And enter the following commands:

>>> from geeks.models import GeeksModel
>>> GeeksModel.objects.create( title="title1", description="description1")
>>> GeeksModel.objects.create(title="title2", description="description2")
>>> GeeksModel.objects.create(title="title3", description="description3")

Next, register the model to view it and its data in the Django admin panel.

In geeks/admin.py:

from django.contrib import admin
from .models import GeeksModel
# Register your models here.
admin.site.register(GeeksModel)

With the backend setup complete, verify that instances have been created by visiting: http://localhost:8000/admin/geeks/geeksmodel/

Create a view and template to display and handle the form. Templates are HTML files used to display data.

In geeks/views.py:

from django.shortcuts import render
from .models import GeeksModel

def list_view(request):
    # dictionary for initial data with field names as keys
    context ={}

    # add the dictionary during initialization
    context["dataset"] = GeeksModel.objects.all()
    return render(request, "list_view.html", context)

Create a template in geeks/templates/list_view.html:

<div class="main">

    {% for data in dataset %}.

    {{ data.title }}<br/>
    {{ data.description }}<br/>
    <hr/>

    {% endfor %}

</div>

Visit: http://localhost:8000/

Similarly, function based views can be implemented with logics for create, update, retrieve and delete views.

Django Function Based Views - CRUD Operations

Function-Based Views in Django also support CRUD operations (Create, Retrieve, Update and Delete), allowing you to interact with database models to perform common web application tasks.

• Create: create or add new entries in a table in the database. 
• Retrieve: read, retrieve, search, or view existing entries as a list (List View) or retrieve a particular entry in detail (Detail View)
• Update: update or edit existing entries in a table in the database 
• Delete: delete, deactivate, or remove existing entries in a table in the database

These operations power common features like user management, blog posts, and product catalogs, making Function-Based Views essential for building dynamic web applications.