Build Your First Django Web App: Step‑by‑Step Guide for Beginners

1. Introduction to Django

1. Web framework overview

Before introducing Django, we need to explain the concept of a web framework. A web framework is a pre‑defined website template that you fill or modify to suit your needs.

Typical web framework architecture is shown below:

Other Python web frameworks such as Tornado, Flask, and WebPy are variations of this architecture; Tornado uses its own asynchronous WSGI, Flask provides a minimal core, while Django uses WSGI and implements most functionality out of the box.

2. MVC/MTV explanation

MVC (Model‑View‑Controller) separates business logic, data, and presentation. In simple terms, it organizes files into separate directories.

Model : defines database‑related content, usually placed in models.py.

View : defines static files such as HTML, CSS, and JavaScript.

Controller : contains the business logic.

Some frameworks rename MVC to MTV, where the “view” becomes the controller and HTML templates are stored in a templates directory.

3. Django’s MTV organization

Django uses urls, ORM, static files, and settings to connect the separated components. A typical workflow is illustrated below:

2. Django project example

1. Installation

Install Python 3.5, pip3, and PyCharm Professional (the free edition does not support Django).

Installation of Django

Download from http://www.cnblogs.com/qianyuliang/p/6729298.html .

2. Create a Django project

Use Django commands in a Linux terminal or Eclipse. In Eclipse choose File → Project, select PyDev/Django, and name the project “mysite”.

Django automatically generates the following directory structure:

The project‑named directory contains configuration files; the templates directory holds HTML files; manage.py is the project management script.

3. Create an app

Each Django project can contain multiple apps, which are relatively independent sub‑modules sharing project resources.

Right‑click mysite → Django → Create application to generate an app folder (e.g., app01).

4. Define URLs

All routes are defined in urls files, mapping browser URLs to business logic.

5. Write business logic

Business logic resides in views.py.

Mapping the “index” URL to the index() function returns a “hello world” string.

6. Run the web service

Remember to add app01 to settings.py, then start the server with python manage.py runserver 127.0.0.1:8000. In Eclipse use Run Configurations.

After a successful start, open the browser at 127.0.0.1:8000.

7. Return HTML files

Instead of a plain string, return an HTML file (e.g., index.html).

8. Use static files

Place CSS, JS, and plugins in a static directory and configure settings.py accordingly.

9. Receive user data

Add a form to index.html for username and password, submit to the index URL, and handle the data in views.py. Disable CSRF protection in settings.py for this demo.

10. Return dynamic pages

Use Django’s template language (similar to Jinja2) to render data dynamically.

11. Use a database

Configure a MySQL database (or use the default SQLite). Define models with fields for name and password, then run python manage.py makemigrations and python manage.py migrate. Update views.py to store and retrieve data.

After restarting the server, user data is persisted in the database.

3. Summary

Django is a powerful, comprehensive Python web framework. While it imposes certain constraints, mastering its core principles—MTV architecture, routing, views, templates, static files, and ORM—allows you to build full‑featured web applications efficiently.