Web app called Learning Log that allows users to log the topics they’re interested in and to make journal entries as they learn about each topic. The Learning Log home page describes the site and invites users to either register or log-in. Once logged in, a user can create new topics, add new entries, and read and edit existing entries.

To work with Django, we’ll first set up a virtual environment. A virtual environment is a place on your system where you can install packages and isolate them from all other Python packages. Separating one project’s libraries from other projects is beneficial and will be necessary when we deploy Learning Log to a server. Create a new directory for the project called learning_log, switch to that directory in a terminal, and enter the following code to create a virtual environment:

learning_log$ python3 -m venv ll_env 
learning_log$

Now we activate the virtual environment using the following command:

learning_log$ source ll_env/bin/activate

you will see : (ll_env)learning_log$

NOTE: If you’re using Windows, use the command ll_env\Scripts\activate (without the word "source") to activate the virtual environment. If you’re using PowerShell, you might need to capitalize "Activate".

(ll_env)learning_log$ deactivate

you will see : learning_log$

ll_env)learning_log$ pip install django

Collecting django

--snip--
Installing collected packages: pytz, django
Successfully installed django-2.2.0 pytz-2018.9 sqlparse-0.2.4 

(ll_env)learning_log$

(ll_env)learning_log$ django-admin startproject learning_log .

(ll_env)learning_log$ ls

learning_log ll_env manage.py

(ll_env)learning_log$ ls learning_log

__init__.py  settings.py  urls.py  wsgi.py

(ll_env)learning_log$ python3 manage.py migrate 

Operations to perform:
    Apply all migrations: admin, auth, contenttypes, sessions

Running migrations:
    Applying contenttypes.0001_initial... OK
    Applying auth.0001_initial... OK
    --snip--
    Applying sessions.0001_initial... OK

(ll_env)learning_log$ ls
db.sqlite3 learning_log ll_env manage.py

Run Server: Let’s make sure that Django has set up the project properly. Enter the runserver command as follows to view the project in its current state:

(ll_env)learning-Log % python manage.py runserver
Watching for file changes with StatReloader
Performing system checks...

System check identified no issues (0 silenced).
February 08, 2021 - 03:14:34
Django version 3.1.6, using settings 'learning_log.settings'
Starting development server at https://127.0.0.1:8000/
Quit the server with CONTROL-C. 

Open a web browser and enter the URL https://localhost:8000/, or https:// 127.0.0.1:8000/ if the first one doesn’t work. You should see something like Figure 18-1, a page that Django creates to let you know all is working properly so far. Keep the server running for now, but when you want to stop the server, press cTrL-C in the terminal where the runserver command was issued.

leave the development server running in the terminal window you opened earlier. Open a new terminal window (or tab), and navigate to the directory that contains manage.py. Activate the virtual environment, and then run the startapp command:

learning_log$ source ll_env/bin/activate
(ll_env)learning_log$ python manage.py startapp learning_logs 
(ll_env)learning_log$ ls
db.sqlite3 learning_log learning_logs ll_env manage.py
(ll_env)learning_log$ ls learning_logs/
__init__.py  admin.py  apps.py  migrations  models.py  tests.py  views.py

The command startapp appname tells Django to create the infrastructure needed to build an app. In the project directory now, we will have a new folder called learning_logs. Django has created init.py , admin.py , apps.py , migrations , models.py , tests.py , views.py files. The most important files are models.py, admin.py, and views.py. We’ll use models.py to define the data we want to manage in our app.

Every time a Model is added we need to migrate the database. Migrate the database and check the output by entering the following commands:

(ll_env)learning_log$ python manage.py makemigrations learning_logs

Migrations for 'learning_logs':
    learning_logs/migrations/0002_entry.py
        - Create model Entry

(ll_env)learning_log$ python manage.py migrate 

Operations to perform:
    --snip--
    Applying learning_logs.0002_entry... OK

A new migration called 0002_entry.py is generated, which tells Django how to modify the database to store information related to the model Entry.