Source address: http://python.usyiyi.cn/documents/django_182/intro/tutorial02.html
Address 2: https://django-intro-zh.readthedocs.io/zh_CN/latest/whats_next/
1,django-admin startproject mysite
2,python manage.py startapp polls
3. Write models.py file in app

import datetime
from django.db import models
from django.utils import timezone

# Create your models here.
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)
    choice_text = models.CharField(max_length=200)
    votes = models.IntegerField(default=0)

    def __str__(self):
        return self.choice_text

4. Python management. py makemigrations to create migration files for these changes
5. Python management. py migrate, update these changes to the database.
6,python manage.py createsuperuser
7. Modify polls/admin.py to allow poll applications to be editable in management sites

from django.contrib import admin

from .models import Question

admin.site.register(Question)

8. Create a model management object (class), and then pass the object (class name) as the second parameter to admin.site.register() to customize the management form.

from django.contrib import admin

# Register your models here.
from .models import Question

class QuestionAdmin(admin.ModelAdmin):
    fields = ['pub_date','question_text']

admin.site.register(Question,QuestionAdmin)

9. Divide the form into field sets. The first element of each tuple in field sets is the title of the field set.

from django.contrib import admin

# Register your models here.
from .models import Question

class QuestionAdmin(admin.ModelAdmin):
    # fields = ['pub_date','question_text']
    fieldsets = [
        (None,              {'fields':['question_text']}),
        ('Time information',{'fields':['pub_date']}),
    ]

admin.site.register(Question,QuestionAdmin)

10. You can add a set of Choice s directly while creating Question objects

from django.contrib import admin

# Register your models here.
from .models import Question,Choice

class ChoiceInline(admin.StackedInline):
    model = Choice
    extra = 3

class QuestionAdmin(admin.ModelAdmin):
    # fields = ['pub_date','question_text']
    fieldsets = [
        (None,              {'fields':['question_text']}),
        ('Time information',{'fields':['pub_date']}),
    ]
    inlines = [ChoiceInline]

admin.site.register(Question,QuestionAdmin)
# admin.site.register(Choice)

This tells Django: Choice objects to be edited in the Question management interface. Provide enough space for three choices by default

11. By default, Django displays the contents returned by str() for each object. But sometimes it would be helpful if we could display individual fields. We use the list_display option to do this.

from django.contrib import admin

# Register your models here.
from .models import Question,Choice

class ChoiceInline(admin.TabularInline):
    model = Choice
    extra = 3

class QuestionAdmin(admin.ModelAdmin):
    # fields = ['pub_date','question_text']
    fieldsets = [
        (None,              {'fields':['question_text']}),
        ('Time information',{'fields':['pub_date']}),
    ]
    inlines = [ChoiceInline]
    list_display = ('question_text','pub_date','was_published_recently')

admin.site.register(Question,QuestionAdmin)
# admin.site.register(Choice)

12. Adding filters and search functions

from django.contrib import admin

# Register your models here.
from .models import Question,Choice

class ChoiceInline(admin.TabularInline):
    model = Choice
    extra = 3

class QuestionAdmin(admin.ModelAdmin):
    # fields = ['pub_date','question_text']
    fieldsets = [
        (None,              {'fields':['question_text']}),
        ('Time information',{'fields':['pub_date']}),
    ]
    inlines = [ChoiceInline]
    list_display = ('question_text','pub_date','was_published_recently')
    list_filter = ['pub_date']
    search_fields = ['question_text']

admin.site.register(Question,QuestionAdmin)
# admin.site.register(Choice)

13. Custom Management Interface Template
14. Modify the view function, modify urlconf, and include urls.py in app
https://django-intro-zh.readthedocs.io/zh_CN/latest/part3/

# polls/urls.py
from django.conf.urls import url
from . import views

urlpatterns = [
    url(r'^$', views.index,name='index'),
    url(r'^(?P<question_id>[0-9]+)/$', views.detail,name='detail'),
    url(r'^(?P<question_id>[0-9]+)/results/$', views.results,name='results'),
    url(r'^(?P<question_id>[0-9]+)/vote/$', views.vote,name='vote'),
]

15. Load the polls/index.html template file and pass it a context

# polls/views.py

from django.http import HttpResponse
from django.template import loader

from .models import Question


def index(request):
    latest_question_list = Question.objects.order_by('-pub_date')[:5]
    template = loader.get_template('polls/index.html')
    context = {
        'latest_question_list': latest_question_list,
    }
    return HttpResponse(template.render(context, request))

16. Shortcut function render

from django.shortcuts import render

# Create your views here.
from django.http import HttpResponse
from .models import Question
from django.template import loader

def index(request):
    latest_question_list = Question.objects.order_by('-pub_date')[:5]

    # output = ','.join([p.question_text for p in latest_question_list])
    # template = loader.get_template('polls/index.html')
    context = {'latest_question_list':latest_question_list}

    return render(request,'polls/index.html',context)

17. Throw 404 errors

# polls/views.py

from django.http import Http404
from django.shortcuts import render

from .models import Question
# ...
def detail(request, question_id):
    try:
        question = Question.objects.get(pk=question_id)
    except Question.DoesNotExist:
        raise Http404("Question does not exist")
    return render(request, 'polls/detail.html', {'question': question})

18. Shortcut function: get_object_of_404()

# polls/views.py

from django.shortcuts import get_object_or_404, render

from .models import Question
# ...
def detail(request, question_id):
    question = get_object_or_404(Question, pk=question_id)
    return render(request, 'polls/detail.html', {'question': question})

19. Remove hard-coded URLs from templates and define URLs by name parameter in the urls() function of polls.urls. You can use the {% url%} tag instead.
20. Add a namespace for the URL name

# mysite/urls.py

from django.conf.urls import include, url
from django.contrib import admin

urlpatterns = [
    url(r'^polls/', include('polls.urls', namespace="polls")),
    url(r'^admin/', include(admin.site.urls)),
]

//Now edit the polls/index.html file from:

<li><a href="{% url 'detail' question.id %}">{{ question.question_text }}</a></li>
//Amend to read:

<li><a href="{% url 'polls:detail' question.id %}">{{ question.question_text }}</a></li>

20. Write view functions to simplify and delete old index, detail, and results views, and replace them with Django's general view (Part 4)
21. Write forms for testing