[Python知识库]Django-MySQL

1、新建项目

django-admin startproject HelloWorld

2、新建数据库runoob

create database runoob default charset=utf8;

3、修改HelloWorld/HelloWorld/settings.py: 文件代码：

DATABASES = { 
    'default': 
    { 
        'ENGINE': 'django.db.backends.mysql',    # 数据库引擎
        'NAME': 'runoob', # 数据库名称
        'HOST': '127.0.0.1', # 数据库地址，本机 ip 地址 127.0.0.1 
        'PORT': 3306, # 端口 
        'USER': 'root',  # 数据库用户名
        'PASSWORD': '123456', # 数据库密码
    }  
}

4、在与 settings.py 同级目录下的 __init__.py 中引入模块和进行配置（安装第三方库：pymysql和mysqlclient）

import pymysql
pymysql.install_as_MySQLdb()

5、创建一个 app。我们使用以下命令创建一个 TestModel 的 app:

django-admin startapp TestModel

6、修改 TestModel/models.py 文件

from django.db import models

# Create your models here.
# 书籍表
class BookInfo(models.Model):
    id = models.AutoField(primary_key=True)
    name = models.CharField(max_length=50)
    btitle = models.CharField(max_length=50)
    bpub_date = models.DateTimeField(auto_now=True)#自动填充当前时间
    bread = models.CharField(max_length=50)
    bcomment = models.CharField(max_length=50)

?7、在 settings.py 中找到INSTALLED_APPS这一项添加TestModel

?8、创建表结构，插入数据

按正常顺序需要数据迁移，用命令来自动创建表。

python manage.py migrate   # 创建表结构

python manage.py makemigrations TestModel  # 让 Django 知道我们在我们的模型有一些变更

python manage.py migrate TestModel

?如果数据库中没有自动生成表，就手动创建：

create table testmodel_bookinfo
(
	id int primary key,
    name varchar(50),
    btitle varchar(50),
    bpub_date DATETIME,
    bread varchar(50),
    bcomment varchar(50)
);

?9、修改HelloWorld/HelloWorld/urls.py: 文件代码

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

urlpatterns = [
    path('admin/', admin.site.urls),
    path('a/', include('TestModel.urls')),
]

10、修改HelloWorld/TestModel/views.py文件

import json
from django.http import HttpResponse, JsonResponse
from django.shortcuts import render

# Create your views here.
from datetime import datetime

from django.views import View

from TestModel.models import BookInfo

class BooksAPIVIew(View):
   """
   查询所有图书、增加图书
   """
   def get(self, request):
       """
       查询所有图书
       路由：GET /books/
       """
       print(BookInfo.objects.all())
       queryset = BookInfo.objects.all()
       book_list = []
       for book in queryset:
           print(book)
           book_list.append({
               'id': book.id,
               'name' : book.name,
               'btitle': book.btitle,
               'bpub_date': book.bpub_date,
               'bread': book.bread,
               'bcomment': book.bcomment,
            #    'image': book.image.url if book.image else ''
           })
       return JsonResponse(book_list, safe=False)

   def post(self, request):
       """
       新增图书
       路由：POST /books/ 
       """
       json_bytes = request.body
       json_str = json_bytes.decode()
       book_dict = json.loads(json_str)

       # 此处详细的校验参数省略

       book = BookInfo.objects.create(
           btitle=book_dict.get('btitle'),
           bpub_date=datetime.strptime(book_dict.get('bpub_date'), '%Y-%m-%d').date()
       )

       return JsonResponse({
           'id': book.id,
           'name' : book.name,
           'btitle': book.btitle,
           'bpub_date': book.bpub_date,
           'bread': book.bread,
           'bcomment': book.bcomment,
           'image': book.image.url if book.image else ''
       }, status=201)


class BookAPIView(View):
   def get(self, request, pk):
       """
       获取单个图书信息
       路由： GET  /books/<pk>/
       """
       try:
           book = BookInfo.objects.get(pk=pk)
       except BookInfo.DoesNotExist:
           return HttpResponse(status=404)

       return JsonResponse({
           'id': book.id,
           'name' : book.name,
           'btitle': book.btitle,
           'bpub_date': book.bpub_date,
           'bread': book.bread,
           'bcomment': book.bcomment,
           'image': book.image.url if book.image else ''
       })

   def put(self, request, pk):
       """
       修改图书信息
       路由： PUT  /books/<pk>
       """
       try:
           book = BookInfo.objects.get(pk=pk)
       except BookInfo.DoesNotExist:
           return HttpResponse(status=404)

       json_bytes = request.body
       json_str = json_bytes.decode()
       book_dict = json.loads(json_str)

       # 此处详细的校验参数省略

       book.btitle = book_dict.get('btitle')
       book.bpub_date = datetime.strptime(book_dict.get('bpub_date'), '%Y-%m-%d').date()
       book.save()

       return JsonResponse({
           'id': book.id,
           'name' : book.name,
           'btitle': book.btitle,
           'bpub_date': book.bpub_date,
           'bread': book.bread,
           'bcomment': book.bcomment,
           'image': book.image.url if book.image else ''
       })

   def delete(self, request, pk):
       """
       删除图书
       路由： DELETE /books/<pk>/
       """
       try:
           book = BookInfo.objects.get(pk=pk)
       except BookInfo.DoesNotExist:
           return HttpResponse(status=404)

       book.delete()

       return HttpResponse(status=204)

11、修改HelloWorld/TestModel/urls.py文件

from . import views
from django.urls import re_path

urlpatterns = [
   re_path(r'^books/$', views.BooksAPIVIew.as_view()),
   re_path(r'^books/(?P<pk>\d+)/$', views.BookAPIView.as_view())
]

12、启动服务

python manage.py runserver 0.0.0.0:8000

13、输入网址：127.0.0.1:8000/a/books/