Django 2 Tutorial for Beginners: Building a CRM

Throughout this beginner's tutorial for Django 2.0, we are going to learn to build web applications with Python and Django. This tutorial assumes no prior experience with Django, so we'll be covering the basic concepts and elements of the Django framework by emphasizing essential theory with practice.

Basically, we are going to learn Django fundamental concepts while building a real world real estate web application starting from the idea to database design to full project implementation and deployment.

This tutorial doesn't only cover fundamental basics of Django but also advanced concepts such as how to use and integrate Django with modern front end frameworks like Angular 2+, Vue and React.

What's Django?

Django is an open source Python based web framework for building web applications quickly.

  • It's a pragmatic framework designed for developers working on projects with strict dead lines.
  • It's perfect for quickly creating prototypes and then continue building them after clients approval.
  • It follows a Model View Controller (MVC) design pattern
  • Django uses the Python language, a general purpose, powerful and feature-rich programming language.

What's MVC?

MVC is a software architectural design pattern which encourages the separation of concerns and effective collaboration between designers and developers when working on the same project. It basically divides or separates your app into three parts:

  • Model: responsible for data storage and management,
  • View: responsible of representing and rendering the user interface or view,
  • Controller: responsible for handling logic to control the user interface and work with data model.

Thanks to MVC, you as a developer can work in the model and controller parts without being concerned with the user interface (left to designers) so if anything changes on the side of designers on the user interface, you can rest assured that you will not be affected.

Introduction to Python

Python is a general purpose programing language that's suitable for developing all kind of applications including web applications. Python is known by a clean syntax and a large standard library which contains a wide range of modules that can be used by developers to build their applications instead of reinventing the wheel.

Here is a list of features and characteristics of Python:

  • Python is an Object Oriented Language just like Java or C++. Also like Java, Python is an interpreted language that runs on top of its own virtual machine which makes it a portable language that can runs across every machine and operating system such as Linux, Windows and MAC.

  • Python is especially popular among the scientific community where it's used for creating numeric applications.

  • Python is also known by the great performance of its runtime environment which makes it a good alternative to PHP for developing web applications.

For more information you can head to http://python.org/ where you can also download Python binaries for supported systems.

For Linux and MAC, Python is included by default so you don't have to install it. For Windows just head over to the official Python website and grab your installer. Just like any normal Windows program, the installation dead process is easy and straightforward.

Why Using Django?

Due to its popularity and large community, Python has numerous web frameworks among them Django. So what makes Django the right choice for you or your next project?

Django is a batteries-included framework

Django includes a set of batteries that can be used to solve common web problems without reinventing the wheel such as:

  • the sites framework,
  • the auth system,
  • forms generation,
  • an ORM for abstracting database systems,
  • and a very powerful templating engine,
  • caching system,
  • RSS generation framework etc.

The Django ORM

Django has a powerful ORM (Object Relational Mapper) which allows developers to use Python OOP classes and methods instead of SQL tables and queries to work with SQL based databases. Thanks to the Django ORM, developers can work with any database system such as MySQL or PostgresSQL without knowing anything about SQL. In the same time the ORM doesn't get in the way. You can write custom SQL anytime you want especially if you need to optimize the queries against your server database for increased performance.

Support for Internationalization: i18n

You can use Django for writing web applications for other languages than English with a lot of ease thanks to its powerful support for internationalization or you can also create multi lingual websites

The Admin Interface

Django is a very suitable framework for quickly building prototypes thanks to its auto-generated admin interface.

You can generate a full fledged admin application that can be used to do all sorts of CRUD operations against your database models you have registered with the admin module using a few lines of code.

Community and Extensive Documentation

Django has a great community that has contributed all sorts of awesome things to Django from tutorials and books to reusable open source packages that extend the core framework to include solutions for even more web development problems without reinventing the wheel or wasting time implementing what other developers have already created.

Django has also one of the most extensive and useful documentation on the web which can gets you up and running with Django in no time.

As a conclusion, if you are looking for a web framework full of features that makes building web applications fun and easy and that has all what you can expect from a modern framework. Django is the right choice for you if you are a Python developer.

  • Python is a portable programming language that can be used anywhere its runtime environment is installed.

  • Django is a Python framework which can be installed on any system which supports the Python language.

In this tutorial part, we are going to see how to install Python and Django on the major available operating systems i.e Windows, Linux and MAC.

Installing Python

Depending on your operating system you may or may not need to install Python. In Linux and MAC OS Python is included by default. You may only need to update it if the installed version is outdated.

Installing Python On Windows

Python is not installed by default on Windows, so you'll need to grab the official installer from the official Python website at http://www.python.org/download/. Next launch the installer and follow the wizard to install Python just like any other Windows program.

Also make sure to add Python root folder to system path environment variable so you can execute the Python executable from any directory using the command prompt.

Next open a command prompt and type python. You should be presented with a Python Interactive Shell printing the current version of Python and prompting you to enter your Python commands (Python is an interpreted language)

Installing Python on Linux

If you are using a Linux system, there is a great chance that you already have Python installed but you may have an old version. In this case you can very easily update it via your terminal depending on your Linux distribution.

For Debian based distributions, like Ubuntu you can use the apt package manager

sudo apt-get install python

This will update your Python version to the latest available version.

For other Linux distributions you should look for equivalent commands to install or update Python which is not a daunting task if you already use a package manager to install packages for your system then you should follow the same process to install or update Python.

Installing Python on MAC OS

Just like Linux, Python is included by default on MAC but in case you have an old version you should be able to update it by going to [http://www.python.org/download/mac/](http://www.python.org/download/mac/ and grab a Python installer for MAC.

Now if you managed to install or update Python on your own system or in case you have verified that you already have an updated version of Python installed on your system let's continue by installing Django.

Installing PIP

PIP is a Python package manager which's used to install Python packages from Python Package Index which is more advanced than easy_install the default Python package manager that's installed by default when you install Python.

You should use PIP instaed of easy_install whenever you can but for installing PIP itself you should use easy_install. So let's first install PIP:

Open your terminal and enter:

$ sudo easy_install pip

You can now install Django on your system using pip

$ sudo pip install django

While you can do this to install Django, globally on your system, it's strongly not recommend. Instead you need to use a virtual environement to install packages.

virtualenv

virtualenv is a tool that allows you to work with multiple Python projects with different or the same (often different and conflicting versions) requirements on the same system without any problems by creating multiple and isolated virtual environments for Python packages.

Now lets first install virtualenv using pip :

$ sudo pip install virtualenv      

Or you can install virtualenv before even installing pip from its official website.

In this case, you don't need to install pip because it comes installed with virtualenv and gets copied into any virtual environment you create.

Creating a Virtual Environment

After installing virtualenv you can now create your first virtual environment using your terminal:

$ cd ~/where-ever-you-want 
$ virtualenv env 

Next you should activate your virtual environment:

$ source env/bin/activate 

Now you can install any Python package using pip inside your created virtual environment.

Lets install Django!

Installing Django

After creating a new virtual environment and activating it. It's time to install Django using pip

$ pip install django 

Django will only be installed on the activated virtual environment not globally.

Now lets summarize what we have done:

  • we first installed Python
  • we then installed pip and virtualenv to install packages from PyPI and create isolated virtual environments for multiple Python projects
  • finally we created a virtual environment and installed Django.

Now that we have installed required development tools including Django framework. It's time for the first real step to start building our real estate application while learning Django essentials from scratch.

Django framework includes a bunch of very useful utilities to create and manage projects that can be accessed from a Python file called django-admin.py that becomes available when we first installed Django.

In this section we are going to see how to:

  • create a new project
  • setup and create the project database
  • start the development server

Create a new Django project

Creating a new Django project is easy and quick so open your terminal or command prompt then enter:

$ django-admin.py startproject crm

This command will take care of creating a bunch of necessary files for the project.

Executing the tree command in the root of our created project will show us the files that were created.

    .
    ├── crm
    │   ├── __init__.py
    │   ├── settings.py
    │   ├── urls.py
    │   └── wsgi.py
    └── manage.py

__init__ is the Python way to mark the containing folder as a Python package which means a Django project is a Python package.

settings.py is the project configuration file. You can use this file to specify every configuration option of your project such as the installed apps, site language and database options etc.

urls.py is a special Django file which maps all your web app urls to the views.

wsgi.py is necessary for starting a wsgi application server.

manage.py is another Django utility to manage the project including creating database and starting the local development server.

These are the basic files that you will find in every Django project. Now the next step is to set up and create the database.

Setting Up the Database

Using your favorite code editor or IDE, open your project settings.py file and lets configure the database.

    DATABASES = {
        'default': {
            'ENGINE': 'django.db.backends.sqlite3',
            'NAME': os.path.join(BASE_DIR, 'db.sqlite3'),
        }
    }

Django works with multiple database systems from simple to advanced systems (both open source and proprietary) such as SQLite, MySQL,PostgreSQL, SQL Server, Oracle etc.

Also you can switch to any database system whenever you want, even after starting developing your web app, without any problems thanks to Django ORM that abstracts how you can work with any database system.

For the sake of simplicity, we'll be using SQLite since it comes already installed with Python so we actually have our database configuration already set up for development. Next for deployment you can use an advanced database system such as MySQL or PostgreSQL by just editing this configuration option.

Finally we need to tell Django to actually create the database and tables. Even if we didn't create actual code or data for our app yet,Django needs to create many tables for its internal use. So lets create the database.

Creating the database and the tables is a matter of issuing this one command.

$ python manage.py migrate 

You should get an output like:

    Operations to perform:
    Apply all migrations: admin, auth, contenttypes, sessions
    Running migrations:
    Applying contenttypes.0001_initial... OK
    Applying auth.0001_initial... OK
    Applying admin.0001_initial... OK
    Applying admin.0002_logentry_remove_auto_add... OK
    Applying contenttypes.0002_remove_content_type_name... OK
    Applying auth.0002_alter_permission_name_max_length... OK
    Applying auth.0003_alter_user_email_max_length... OK
    Applying auth.0004_alter_user_username_opts... OK
    Applying auth.0005_alter_user_last_login_null... OK
    Applying auth.0006_require_contenttypes_0002... OK
    Applying auth.0007_alter_validators_add_error_messages... OK
    Applying auth.0008_alter_user_username_max_length... OK
    Applying sessions.0001_initial... OK

Since we are using a SQLite database, you should also find a sqlite file under the current directory:

    .
    ├── db.sqlite3
    ├── crm
    │   ├── __init__.py
    │   ├── __init__.pyc
    │   ├── settings.py
    │   ├── settings.pyc
    │   ├── urls.py
    │   ├── urls.pyc
    │   └── wsgi.py
    └── manage.py

Starting the local development server

Django has a local development server that can be used while developing your project. It's a simple and primitive server which's suitable only for development not for production.

To start the local server for your project, you can simply issue the following command inside your project root directory:

$ python manage.py runserver

Next navigate to http://localhost:8000/ with a web browser.

You should see a web page with a message:

It worked!
Congratulations on your first Django-powered page.

Next, start your first app by running python manage.py startapp [app_label].

You're seeing this message because you have DEBUG = True in your Django settings file and you haven't configured any URLs. Get to work!

Conclusion

To conclude this tutorial, lets summarize what we have done: We have created a new Django project, created and migrated a SQLite database and started a local development server. In the next tutorial we are going to start creating our crm prototype.


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