~$ which python3 
show >> path_to_be_copied

~$ virtualenv -p path_to_be_copied vir_name

~$ source vir_name/bin/activate

// to leave the virtualenv
(vir_name) ~$ deactivate 

(vir_name) ~$ pip list

(vir_name) ~$ pip3 install django

(vir_name) ~$ mkdir proj_name


(vir_name) ~$cd proj_name

(vir_name) proj_name$ django-admin startproject site_name_top_level

(vir_name) proj_name$ cd site_name_top_level

(vir_name) site_name$ ls

               site_name_sub_level/settings.py + urls.py
               
               manage.py
               
               (sqlite3 waits to be created)
               
               (blog app waits to be created)/models.py + views.py + admin.py + migration + apps.py

python manage.py runserver

python manage.py makemigrations

python manage.py migrate

python manage.py startapp kblog

python3 manage.py createsuperuser

Username (leave blank to use 'katesandroid'): xxxxx
Email address: [email protected]
Password: 
Password (again): 
Superuser created successfully.
(k0219) KatesAndroiddeMacBook-Pro:site0219 katesandroid$ python manage.py runserver
Watching for file changes with StatReloader
Performing system checks...

python manage.py shell



>>> from kblog.models import Post
>>> Post.objects.all()
>>> 
>>> 
<QuerySet []>


>>> Post.objects.create(author=user, title='Sample title', text='Test')
>>> 
Traceback (most recent call last):
  File "<console>", line 1, in <module>
NameError: name 'user' is not defined
>>> Post.objects.create(author='kate chen', title='Sample title', text='Test')
ValueError: Cannot assign "'kate chen'": "Post.author" must be a "User" instance.


>>> from django.contrib.auth.models import User
>>> User.objects.all()
<QuerySet []>


>>> user = User.objects.get(username='Poupou Chen')
Traceback (most recent call last):
  File "<console>", line 1, in <module>
  File "/Users/katesandroid/k0219/lib/python3.8/site-packages/django/db/models/manager.py", line 85, in manager_method
    return getattr(self.get_queryset(), name)(*args, **kwargs)
  File "/Users/katesandroid/k0219/lib/python3.8/site-packages/django/db/models/query.py", line 429, in get
    raise self.model.DoesNotExist(
django.contrib.auth.models.User.DoesNotExist: User matching query does not exist.


>>> from django.contrib.auth.models import User
>>> User.objects.all()
<QuerySet []>


>>> from django.contrib.auth.models import User
>>> user = User.objects.create_user('Poupou', '[email protected]', '0123456789')
>>> user.save()
>>> 

>>> from django.contrib.auth.models import User
>>> User.objects.all()
<QuerySet [<User: Poupou>]>


>>> user = User.objects.get(username='Poupou')
>>> Post.objects.create(author = user, title = 'Cats Lovely Home', text = 'Test')
<Post: Cats Lovely Home>


>>> Post.objects.all()
<QuerySet [<Post: Cats Lovely Home>]>


>>> post = Post.objects.get(id=1)
>>> post.publish()
>>> 
>>> Post.objects.filter(published_date__isnull=False)
<QuerySet [<Post: Cats Lovely Home>]>
>>> exit()