Django 2 ----- database and admin

One . The view function

(1). Basic concepts

The function of view is to receive and send Web request , It is mainly used to deal with the business logic of the website

(2). Develop the first view

stay polls/views.py Next , Write the following code

from django.shortcuts import render
from django.http import HttpResponse
# Create your views here.

def index(request):
    return HttpResponse(" Welcome to the voting system ！")

notes ：request This parameter must be passed , What is it? I will introduce it later
After writing the view function , First in poll Configure distributed routing under the directory , Create a new one urls.py file , Write the following code

from django.urls import path
from . import views

urlpatterns = [
    path('', views.index, name="index"),
]

Go to the main directory again urls.py Include this route

from django.contrib import admin
from django.urls import path, include

urlpatterns = [
    path('admin/', admin.site.urls),
    path('index', include('poll.urls')),
]

Open it in a browser ”http://127.0.0.1:8000/index“, If it's not wrong , You should see the page

Two . Configuration of database

Here we use MySQL database
Direct access to settings.py, Probably 76 The position of the line
First of all mysql Create the corresponding database in

DATABASES = {
    
    'default': {
    
        'ENGINE': 'django.db.backends.mysql',
        'NAME': 'test1_0719', #  Names can be chosen at will 
        'USER':'root',
        'PASSWORD':'123456',
        'HOST':'127.0.0.1', #  Local loopback address 
        'PORT':'3306', #  Default port number 3306
    }
}

3、 ... and . Build a model

stay poll/models.py Write the following code ：

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(verbose_name='date published')

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

    def __str__(self):
        return self.question_text

class Choice(models.Model):
    question = models.ForeignKey(Question, on_delete=models.CASCADE)
    choice_text = models.CharField(max_length=200)
    votes = models.IntegerField(default=0) #  Integer types , Mapping to the database will become 11 Bit int type 

    def __str__(self):
        return self.choice_text

Then execute the following command on the command line ：

python3 manage.py makemigrations

python3 manage.py migrate

These two script commands are to tell MySQL database ,models A change has taken place .

Four . Admin modular

python manage.py createsuperuser

Then follow the command line
Type in the browser http://127.0.0.1:8000/admin/, You can go in superuser Interface

stay poll/admin.py Enter the following code

from django.contrib import admin

# Register your models here.
from . models import Question
admin.site.register(Question)

Refresh the page to get a new interface , Then click the plus sign to edit your own question .
Now we have a back-end page , But there's no front page , This is in Django—3 We will talk about .