Django CRUD (создание, получение, обновление, удаление) Представления на основе функций
Django - это веб-фреймворк на основе Python, который позволяет быстро создавать веб-приложения без всех проблем с установкой или зависимостями, которые обычно возникают с другими фреймворками. Django основан на архитектуре MVT (шаблон представления модели) и вращается вокруг операций CRUD (создание, получение, обновление, удаление). CRUD лучше всего можно объяснить как подход к созданию веб-приложения Django. В общем случае CRUD означает выполнение операций Create, Retrieve, Update и Delete над таблицей в базе данных. Давайте обсудим, что на самом деле означает CRUD,
Создать - создать или добавить новые записи в таблицу в базе данных.
Получить - читать, извлекать, искать или просматривать существующие записи в виде списка (представление списка) или извлекать конкретную запись в деталях (подробное представление)
Обновить - обновить или отредактировать существующие записи в таблице в базе данных.
Удалить - удалить, деактивировать или удалить существующие записи в таблице в базе данных.
Django CRUD (создание, получение, обновление, удаление) представлений на основе функций
Illustration of How to create and use CRUD view 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.
- 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 geeks/models.py
,
# import the standard Django Model # from built-in library 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 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,
from django import forms from .models import GeeksModel # creating a form class GeeksForm(forms.ModelForm): # create meta class class Meta: # specify model to be used model = GeeksModel # specify fields to be used fields = [ "title" , "description" , ] |
Create View
Create View refers to a view (logic) to create an instance of a table in the database. It is just like taking an input from a user and storing it in a specified table.
In geeks/views.py
,
from django.shortcuts import render # relative import of forms from .models import GeeksModel from .forms import GeeksForm def create_view(request): # dictionary for initial data with # field names as keys context = {} # add the dictionary during initialization form = GeeksForm(request.POST or None ) if form.is_valid(): form.save() context[ "form" ] = form return render(request, "create_view.html" , context) |
Create a template in templates/create_view.html
,
< form method = "POST" enctype = "multipart/form-data" > <!-- Security token --> {% csrf_token %} <!-- Using the formset --> {{ form.as_p }} < input type = "submit" value = "Submit" > </ form > |
Now visit http://localhost:8000/
To check complete implementation of Function based Create View, visit Create View – Function based Views Django.
Retrieve View
Retrieve view is basically divided into two types of views Detail View and List View.
List View
List View refers to a view (logic) to list all or particular instances of a table from the database in a particular order. It is used to display multiple types of data on a single page or view, for example, products on an eCommerce page.
In geeks/views.py,
from django.shortcuts import render # relative import of forms 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 templates/list_view.html
,
< div class = "main" > {% for data in dataset %}. {{ data.title }}< br /> {{ data.description }}< br /> < hr /> {% endfor %} </ div > |
Now visit http://localhost:8000/
To check complete implementation of Function based List View, visit List View – Function based Views Django
Detail View
Detail View refers to a view (logic) to display a particular instnace of a table from the database with all the necessary details. It is used to display multiple types of data on a single page or view, for example, profile of a user.
In geeks/views.py
,
from django.urls import path # importing views from views..py from .views import detail_view urlpatterns = [ path( "<id>" , detail_view ), ] |
Let’s create a view and template for the same. In geeks/views.py
,
from django.shortcuts import render # relative import of forms from .models import GeeksModel # pass id attribute from urls def detail_view(request, id ): # dictionary for initial data with # field names as keys context = {} # add the dictionary during initialization context[ "data" ] = GeeksModel.objects.get( id = id ) return render(request, "detail_view.html" , context) |
Create a template in templates/Detail_view.html
,
< div class = "main" > <!-- Specify fields to be displayed --> {{ data.title }}< br /> {{ data.description }}< br /> </ div > |
Let’s check what is there on http://localhost:8000/1
To check complete implementation of Function based Detail View, visit Detail View – Function based Views Django
Update View
Update View 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 geeksforgeeks.
In geeks/views.py
,
from django.shortcuts import (get_object_or_404, render, HttpResponseRedirect) # relative import of forms from .models import GeeksModel from .forms import GeeksForm # after updating it will redirect to detail_View def detail_view(request, id ): # dictionary for initial data with # field names as keys context = {} # add the dictionary during initialization context[ "data" ] = GeeksModel.objects.get( id = id ) return render(request, "detail_view.html" , context) # update view for details def update_view(request, id ): # dictionary for initial data with # field names as keys context = {} # fetch the object related to passed id obj = get_object_or_404(GeeksModel, id = id ) # pass the object as instance in form form = GeeksForm(request.POST or None , instance = obj) # save the data from the form and # redirect to detail_view if form.is_valid(): form.save() return HttpResponseRedirect( "/" + id ) # add form dictionary to context context[ "form" ] = form return render(request, "update_view.html" , context) |
Now create following templates in templates
folder,
In geeks/templates/update_view.html
,
< div class = "main" > <!-- Create a Form --> < form method = "POST" > <!-- Security token by Django --> {% csrf_token %} <!-- form as paragraph --> {{ form.as_p }} < input type = "submit" value = "Update" > </ form > </ div > |
In geeks/templates/detail_view.html
,
< div class = "main" > <!-- Display attributes of instance --> {{ data.title }} < br /> {{ data.description }} </ div > |
Let’s check if everything is working, visithttp://localhost:8000/1/update.
To check complete implementation of Function based update View, visit Update View – Function based Views Django
Delete View
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.
In geeks/views.py
from django.shortcuts import (get_object_or_404, render, HttpResponseRedirect) from .models import GeeksModel # delete view for details def delete_view(request, id ): # dictionary for initial data with # field names as keys context = {} # fetch the object related to passed id obj = get_object_or_404(GeeksModel, id = id ) if request.method = = "POST" : # delete object obj.delete() # after deleting redirect to # home page return HttpResponseRedirect( "/" ) return render(request, "delete_view.html" , context) |
Now a url mapping to this view with a regular expression of id
,
In geeks/urls.py
from django.urls import path # importing views from views..py from .views import delete_view urlpatterns = [ path( "<id>/delete" , delete_view ), ] |
Template for delete view includes a simple form confirming whether user wants to delete the instance or not. In geeks/templates/delete_view.html
,
< div class = "main" > <!-- Create a Form --> < form method = "POST" > <!-- Security token by Django --> {% csrf_token %} Are you want to delete this item ? < input type = "submit" value = "Yes" /> < a href = "/" >Cancel </ a > </ form > </ div > |
Everything ready, now let’s check if it is working or not, visit http://localhost:8000/2/delete
To check complete implementation of Function based Delete View, visit Delete View – Function based Views Django
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