TungNT (Blue)

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====== Django ======

https://docs.djangoproject.com/en/5.1/contents

<code python>
(venv) % python -m pip install Django

>>> import django
>>> print(django.get_version())
4.2.1

(venv) % python -m django --version
4.2.1
</code>

====== Creating a project ======

<code python>
% django-admin startproject django_blue
</code>

===== The development server =====

<code python>
(django5.1) tungnt@MacBook-Pro-cua-Nguyen-2 django_blue % python manage.py runserver
Watching for file changes with StatReloader
Performing system checks...

System check identified no issues (0 silenced).

You have 18 unapplied migration(s). Your project may not work properly until you apply the migrations for app(s): admin, auth, contenttypes, sessions.
Run 'python manage.py migrate' to apply them.
August 28, 2024 - 15:13:33
Django version 5.1, using settings 'django_blue.settings'
Starting development server at http://127.0.0.1:8000/
Quit the server with CONTROL-C.
</code>

===== Creating the app =====

<code python>
% python manage.py startapp polls
</code>

===== Write your first view =====

<file python polls/views.py>
from django.http import HttpResponse

def index(request):
    return HttpResponse("Hello, world. You're at the polls index.")
</file>

<file python polls/urls.py>
from django.http import HttpResponse

def index(request):
    return HttpResponse("Hello, world. You're at the polls index.")
</file>

<file python django_blue/urls.py>
from django.contrib import admin
from django.urls import include, path

urlpatterns = [
    path('admin/', admin.site.urls),
    path("polls/", include("polls.urls")),
]
</file>

<code>
$ python manage.py runserver
</code>

===== Migrations =====

<code python>
(django5.1) tungnt@MacBook-Pro-cua-Nguyen-2 django_blue % python 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
  Applying admin.0001_initial... OK
  Applying admin.0002_logentry_remove_auto_add... OK
  Applying admin.0003_logentry_add_action_flag_choices... 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 auth.0009_alter_user_last_name_max_length... OK
  Applying auth.0010_alter_group_name_max_length... OK
  Applying auth.0011_update_proxy_permissions... OK
  Applying auth.0012_alter_user_first_name_max_length... OK
  Applying sessions.0001_initial... OK
</code>

===== Creating models =====

<file python polls/models.py>
from django.db import models

class Question(models.Model):
    question_text = models.CharField(max_length=200)
    pub_date = models.DateTimeField("date published")

class Choice(models.Model):
    question = models.ForeignKey(Question, on_delete=models.CASCADE)
    choice_text = models.CharField(max_length=200)
    votes = models.IntegerField(default=0)
</file>

<file python django_blue/settings.py>
INSTALLED_APPS = [
    ...
    "polls.apps.PollsConfig",
]
</file>

<code bash>
(django5.1) tungnt@MacBook-Pro-cua-Nguyen-2 django_blue % python manage.py makemigrations polls
Migrations for 'polls':
  polls/migrations/0001_initial.py
    + Create model Question
    + Create model Choice
    
(django5.1) tungnt@MacBook-Pro-cua-Nguyen-2 django_blue % python manage.py migrate
Operations to perform:
  Apply all migrations: admin, auth, contenttypes, polls, sessions
Running migrations:
  Applying polls.0001_initial... OK
</code>

===== Django shell =====

<code bash>
(django5.1) tungnt@MacBook-Pro-cua-Nguyen-2 django_blue % python manage.py shell
Python 3.11.6 (main, Oct  2 2023, 13:45:54) [Clang 15.0.0 (clang-1500.0.40.1)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
(InteractiveConsole)
>>> from polls.models import Choice, Question
>>> Question.objects.all()
<QuerySet []>
>>> from django.utils import timezone
>>> q = Question(question_text="What's new?", pub_date=timezone.now())
>>> q.save()
>>> q.id
1
>>> q.question_text
"What's new?"
>>> q.pub_date
datetime.datetime(2024, 8, 29, 7, 24, 30, 119985, tzinfo=datetime.timezone.utc)
>>> q.question_text = "What's up?"
>>> q.save()
>>> Question.objects.all()
<QuerySet [<Question: Question object (1)>]>
</code>

<file python polls/models.py>
import datetime
from django.db import models
from django.utils import timezone

class Question(models.Model):
    question_text = models.CharField(max_length=200)
    pub_date = models.DateTimeField("date published")

def __str__(self):
        return self.question_text

def was_published_recently(self):
        return self.pub_date >= timezone.now() - datetime.timedelta(days=1)

class Choice(models.Model):
    question = models.ForeignKey(Question, on_delete=models.CASCADE)
    choice_text = models.CharField(max_length=200)
    votes = models.IntegerField(default=0)

def __str__(self):
        return self.choice_text    
</file>

<code bash>
(django5.1) tungnt@MacBook-Pro-cua-Nguyen-2 django_blue % python manage.py shell
Python 3.11.6 (main, Oct  2 2023, 13:45:54) [Clang 15.0.0 (clang-1500.0.40.1)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
(InteractiveConsole)
>>> 
>>> from polls.models import Choice, Question
>>> Question.objects.all()
<QuerySet [<Question: What's up?>]>
>>> Question.objects.filter(id=1)
<QuerySet [<Question: What's up?>]>
>>> Question.objects.filter(question_text__startswith="What")
<QuerySet [<Question: What's up?>]>
>>> 
>>> from django.utils import timezone
>>> current_year = timezone.now().year
>>> Question.objects.get(pub_date__year=current_year)
<Question: What's up?>
>>> 
>>> Question.objects.get(id=2)
Traceback (most recent call last):
...
    raise self.model.DoesNotExist(
polls.models.Question.DoesNotExist: Question matching query does not exist.
>>> Question.objects.get(pk=1)
<Question: What's up?>
>>> q = Question.objects.get(pk=1)
>>> q.was_published_recently()
True
>>> q = Question.objects.get(pk=1)
>>> q.choice_set.all()
<QuerySet []>
>>> q.choice_set.create(choice_text="Not much", votes=0)
<Choice: Not much>
>>> q.choice_set.create(choice_text="The sky", votes=0)
<Choice: The sky>
>>> c = q.choice_set.create(choice_text="Just hacking again", votes=0)
>>> c.question
<Question: What's up?>
>>> q.choice_set.all()
<QuerySet [<Choice: Not much>, <Choice: The sky>, <Choice: Just hacking again>]>
>>> q.choice_set.count()
3
>>> Choice.objects.filter(question__pub_date__year=current_year)
<QuerySet [<Choice: Not much>, <Choice: The sky>, <Choice: Just hacking again>]>
>>> c = q.choice_set.filter(choice_text__startswith="Just hacking")
>>> c.delete()
(1, {'polls.Choice': 1})
</code>

====== Django Admin ======

<code bash>
% python manage.py createsuperuser
</code>

<file python polls/admin.py>
from django.contrib import admin
from .models import Question

admin.site.register(Question)
</file>

====== Views ======

https://docs.djangoproject.com/en/5.1/intro/tutorial03/

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