DJANGO TUTORIAL

 

In this blog I am explaining about how to create a basic app using the Django –python web framework, if you don’t know about the Django framework please refer the blog below,

Reference link : https://mayura-apptech.blogspot.com/2022/07/introduction-about-django-python-web.html

 

GETTING STARTED WITH DJANGO:

Requirements:

Python should be installed                                      

Pip = package manager

 

CREATING THE VIRTUAL ENVIRONMENT:

Before you create a project you need a virtual Environment to isolate the code from the other projects and for the security.

You can create a virtual environment by using the following syntax,

            Python –m  venv environment_name

This will create a folder/directory with the environment name.

 

You can activate the virtual environment .

              Environment name/scripts/actiavte

You can see the result once it is activated.

Output:

PS C:\Users\sugum\OneDrive\my_django> my_django/Scripts/activate

(my_django) PS C:\Users\sugum\OneDrive\my_django>

 

INSTALLING  DJANGO:

You can install django using the following syntax,

               Pip install django

 

CREATING THE PROJECT:

After creating the virtual environment the first step is to create the project folder

By using the following syntax you can create the project folder inside the virtual environment. 

              Django-admin  startprojecrt  project_name

The project folder will contains the following files,

 

RUN THE PROJECT:

Navigate to the project folder , by entering  the following  syntax you can run the project on the browser.

                      Python manage.py  runserver

 

CREATING THE APP:

We have a Django project! The next step is to make an app in your project.

You cannot have a web page created with Django without an app

               Python manage.py startapp appname

 

I will name my app blog.

If the server is still running, and you are not able to write commands, press ctrl+c to stop the server and you should be back in the virtual environment.

It will create the application folder inside the project folder with the following files.

All the file in the folder have specific meaning.

 

DJANGO VIEWS:

Django views are Python functions that takes http requests and returns http response, like HTML documents.

A web page that uses Django is full of views with different tasks and missions.

Views are usually put in a file called views.py located on your app's folder.

 

There is views .py in my app (blog) folder, I open the views.py file and add the content like below,

from django.http import HttpResponse

def index(request):

return HttpResponse("Hello world!")

 

This is a simple example on how to send a response back to the browser.

But how can we execute the view? Well, we must call the view via a URL.

 

URLS:

Create a file named urls.py, in the same application folder, and add the code inside the file.

from django.urls import path

from . import views

 

urlpatterns = [

    path('', views.index, name='index'),

]

The urls.py file you just created is specific for the blog application. We have to do some routing in the project directory  demo as well. 

There is a file called urls.py on the demo folder, open that file and add the include module in the import statement, and also add a path() function in the urlpatterns[] list, with arguments that will route users that comes in via 127.0.0.1:8000/blog/ 

Now run the server you will get the webpage result in the browser.

 

TEMPLATES:

Templates are used to define the layout of the webpage , Django follows HTML as the template language.

Create a templates folder in the application folder and create a html file inside that  for the webpages like below,

 

Them modify the views.py like below,

from django.http import HttpResponse

from django.template import loader

 

def index(request):

  template = loader.get_template('blog.html')

  return HttpResponse(template.render())

then open the settings.py in the project folder and add our app in the installed apps list.

 

Then run the server you will get the webpage result in the browser.

 

DJANGO MODELS:

Model means a table inside a database.

SQLite database:

When we created the Django project, we got an empty SQLite database. It was created in the demo root folder.

We will use this database.

Create Table (Model)

To create a new table, we must create a new model.

In the /blog/ folder, open the models.py file. It is almost empty by default, with only an import statement and a comment:

To add a Members table in our database, start by creating a Members class, and describe the table fields in it:

from django.db import models

 

class blog(models.model):

    blog_title=models.CharField(max_length=100)

    blog_content=models.CharField(max_length=10000)

    published_date=models.DateField(max_length=15)

 

then navigate to the project folder and run the following comment,

                 py manage.py makemigrations blog

 

which will result in,

Migrations for 'blog':

  blog\migrations\0001_initial.py

    - Create model blog

(my_django) PS C:\Users\sugum\OneDrive\my_django\demo>

 

Django creates a file with any new changes and stores the file in the /migrations/ folder.

Next time you run py manage.py migrate Django will create and execute an SQL statement, based on the content of the new file in the migrations folder.

Run the migrate command:

                py manage.py migrate

The SQL statement created from the model is:

migrations.CreateModel(

            name='blog',

            fields=[

                ('id', models.BigAutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),

                ('blog_title', models.CharField(max_length=100)),

                ('blog_content', models.CharField(max_length=100)),

                ('published_date', models.DateField(max_length=15)),

            ],

        ),

 

Now the blog table is empty we should add the records.

 

ADD RECORDS:

let's write Python code directly in the Python interpreter (Python shell) and add some blog in our database, without the user interface.

To open a Python shell, type this command:

               py manage.py shell

it will open a interactive console in the terminal.

after the three >>> write the following

                      >>> from blog.models import blog

Hit [enter] and write this to look at the empty Members table:

                         Blog.objects.all()

This should give you an empty QuerySet object, like this:

                         <QuerySet []>

A QuerySet is a collection of data from a database.

You can add a blog record by following comment,

>>> blog1=blog(blog_title='demo_blog', blog_content='demo_content', published_date='2022-07-08')

then save the values in database,and view the values if it is saved,

blog.save(blog1)

>>> blog.objects.all().values()

<QuerySet [{'id': 1, 'blog_title': 'demo_blog', 'blog_content': 'demo_content', 'published_date': datetime.date(2022, 7, 8)}]>

 

ADD MULTIPLE RECORDS:

You can also add multiple records by making a list of blogs and execute .save() comment.

>>> blog2=blog(blog_title='demo_blog1', blog_content='demo_content1', published_date='2022-07-08')

>>> blog3=blog(blog_title='demo_blog2', blog_content='demo_content2', published_date='2022-07-08')

>>> blogs=[blog2, blog3]

>>> for x in blogs:

...     blog.save(x)

...

>>> blog.objects.all().values()

It will give a output like,

<QuerySet [{'id': 1, 'blog_title': 'demo_blog', 'blog_content': 'demo_content', 'published_date': datetime.date(2022, 7, 8)}, {'id': 2, 'blog_title': 'demo_blog1', 'blog_content': 'demo_content1', 'published_date': datetime.date(2022, 7, 8)}, {'id': 3, 'blog_title': 'demo_blog2', 'blog_content': 'demo_content2', 'published_date': datetime.date(2022, 7, 8)}]>

 

VIEW IN BROWSER:

We want to see the result in a web page, not in a Python shell environment.

To see the result in a web page, we can create a view for this particular task.

For that we are changing the index template as follows

And modify the views.py as,

Now exit the shell using quit() navigate to the project folder and run the server

Now you can see the result in the browser.