Building Websites with Django: Build and Deploy Professional Websites with Python Programming and the Django Framework (English Edition)

The first is to start with Models (database layer) followed by creating views. Once the views are ready, then you can write your urls.py mapping to the views. Finally, templates should be designed as per the urlspattens in urls.py and views in views.py. This approach can be referred to as backend focused.

In Django, if there is a ForeignKey element, then the related element will also be deleted unless on_delete = CASCADE is changed in the model definition.

bool(): This is used to check whether the QuerySet has any result.

Iteration: You can write a QuerySet and iterate over it. For example, you have a database of books. You can write a QuerySet and iterate over the returned data to access each of the different records one at a time.

The QuerySet can be written for different kinds of purposes but it will not interact with databse unless it is evaluated.

Django comes with a powerful database-abstraction API that allows you to create, retrieve, update, and delete objects easily. The Django ORM is compatible with MySQL, PostgreSQL, SQLite, and Oracle. Remember that you can define the database of your project by editing the DATABASES setting in the settings.py file of your project. Django can work with multiple databases at a time and you can even program database routers that handle the data in any way you like.

This is because you have set unique = True in your class definition models.py. This ensures that no duplicate value is accepted for this field.

You can also control what the name of your model classes are displayed in different classes by subclasses in the model classes.

Once you have created your app, you need to tell Django that you have created an app so that Django can implement its features on that app. To do this, open settings.py in your project and add your app name in the list of INSTALLED_APPS as shown in the following screenshot:

So, go to your terminal and shut down the server. Then, execute the python manage.py startapp student command: