Building Web Applications with Django from Scratch

Introduction to Django

Django is a high-level Python web framework that enables rapid development of secure and maintainable websites. Built by experienced developers, it takes care of much of the hassle of web development, so you can focus on writing your app without needing to reinvent the wheel. It’s free and open source.

Django is designed to help developers take applications from concept to completion as quickly as possible. It follows the Model-View-Controller (MVC) architectural pattern, which separates an application into three interconnected parts: the Model (database schema and queries), the View (how the information is presented), and the Controller (handles user interaction).

One of the key features of Django is its built-in admin interface. This allows you to manage data in your application through a web-based interface, without having to write any code. It also includes an Object-Relational Mapping (ORM) system, which allows you to interact with your database using Python code instead of writing SQL queries.

Getting Started with Django

To get started with Django, you’ll need to have Python and pip (Python’s package manager) installed on your computer. Once you have those, you can install Django using pip by running the command `pip install django` in your terminal.

Once Django is installed, you can create a new project by running the command `django-admin startproject mysite`. This will create a new directory called mysite, which will contain the basic structure of your new Django project. You can then start the development server by navigating to the new directory and running the command `python manage.py runserver`.

Django comes with a built-in development server that you can use to test your application. To view your new Django project in a web browser, navigate to `http://127.0.0.1:8000/` in your web browser. You should see a “Congratulations” page, which means that your new Django project is up and running!

Creating a Django App

Once you have your Django project set up, you can start building your application. In Django, an application is a module that performs a specific function. To create a new app, navigate to your project directory and run the command `python manage.py startapp myapp`. This will create a new directory called myapp, which will contain the basic structure of your new Django app.

Next, you’ll need to define your models. Models define the structure of your database and the relationships between different pieces of data. To define your models, open the `models.py` file in your app directory and define your model classes.

Once you have defined your models, you can create your views. Views are Python functions that take a web request and return a web response. To define your views, open the `views.py` file in your app directory and define your view functions. Finally, you’ll need to define your URLs. URLs map URLs to views. To define your URLs, open the `urls.py` file in your app directory and define your URL patterns.

Building a Database with Django

Now that you have your app set up, you can start building your database. Django comes with a built-in ORM (Object-Relational Mapping) system, which allows you to interact with your database using Python code instead of writing SQL queries. To use the ORM, you’ll need to define your models.

Models are defined in the `models.py` file in your app directory. A model is a Python class that subclasses `django.db.models.Model`. Each model represents a database table. Fields on the model represent columns in the table. Django provides a wide range of field types, including CharField, TextField, IntegerField, and DateTimeField.

Once you have defined your models, you can create your database by running the command `python manage.py migrate`. This will create the tables in your database based on your models. You can then use the ORM to add, update, and delete records in your database using Python code.

Summary

In this blog post, we’ve covered the basics of building web applications with Django, a high-level Python web framework. Django is a powerful tool for quickly building web applications, with a built-in admin interface, ORM system, and development server. To get started with Django, you can install it using pip, create a project using `django-admin startproject`, and start the development server using `python manage.py runserver`.

Once you have your project set up, you can start building your application by creating a new app using `python manage.py startapp`. You can define your models in the `models.py` file, your views in the `views.py` file, and your URLs in the `urls.py` file. You can then create your database using the ORM by running `python manage.py migrate`.

Django is a powerful tool for quickly building web applications. With its built-in admin interface, ORM system, and development server, you can focus on writing your app without needing to reinvent the wheel. Whether you’re building a simple web application or a complex web platform, Django is a great choice for your next web development project.