初始化操作

创建app

python manage.py startapp appname

MySQL连接

SETTING.py

DATABASES = {
    'default': {
        'ENGINE': 'django.db.backends.mysql',
        'NAME': 'xxx',
        'HOST':'localhost',
        'PORT':'3306',
        'USER':'username',
        'PASSWORD':'password'
    }
}

LANGUAGE_CODE = 'zh-hans'

init.py

import pymysql
pymysql.install_as_MySQLdb()

数据库模型(models.py)

from Django.db import models

class xxx(models.Model):
    a = models.AutoField(primary_key=True)
    ……
    
    class Meta:
        db_table='tableName'

数据库迁移

python manage.py makemigrations
python manage.py migrate

mongoDB连接

djongo

安装

1. 必须完全按照以下版本安装引用来源

   asgiref==3.5.0
   Django==4.0.3
   djongo==1.3.6
   dnspython==2.2.1
   pymongo==3.12.1
   python-snappy==0.6.1
   pytz==2022.1
   sqlparse==0.2.4

2. 在您的项目settings.py文件中，添加：

   DATABASES = {
       'default': {
           'ENGINE': 'djongo',
           'NAME': 'your-db-name',
       }
   }

   setting.py配置数据库

   DATABASES = {
           'default': {
               'ENGINE': 'djongo',
               'NAME': 'mdb',
               'ENFORCE_SCHEMA': False,
               'CLIENT': {
                   'host': 'ip',
                   'port': 27017,
                   'username': 'xx',
                   'password': 'xx',
                   'authSource': 'mdb',
                   'authMechanism': 'SCRAM-SHA-1'
               },
           }
       }

定义模型

Blog是一个抽象类，相当于二级集合，在下面Entry集合中的blog字段里面用

from djongo import models

class Blog(models.Model):
    name = models.CharField(max_length=100)

    class Meta:
        abstract = True  
        //定义抽象类后不会在数据库中建表

class Entry(models.Model):
    blog = models.EmbeddedField(
        model_container=Blog
    )    
    headline = models.CharField(max_length=255)    

在view的自定义函数中这样用。通过字典的形式给blog集合内的值赋值

e = Entry()
e.blog = {
    'name': 'Djongo'
}
e.headline = 'The Django MongoDB connector'
e.save()

报错处理

1. Array and Embedded Fields vs Error Abstract models cannot be instantiated

在读取数据库时报错，抽象类不能被实例化。说明blog这个字段出现了问题，无法读取数据库

解决办法

• 根据文档的说法在Model模型中添加一个objects字段，示例如下

  class Entry(models.Model):
  blog = models.EmbeddedField(
      model_container=Blog,
  )
  headline = models.CharField(max_length=255)    
  objects = models.DjongoManager()    

• 添加objects字段后就就可以使用pymongo的命令来读取数据库了

  index = [i for i in Entry.objects.mongo_aggregate([
              {
                  '$match': {
                      'headline': 'xx'
                  }
              },
          ])]
  
  return index

2.Object of type ‘ObjectId’ is not JSON serializable

读取数据库后通过JsonResponse返回报错

mongodb读取后返回的是一个orderdict（有序字典）它是有元素的先后顺序的。通过Json.load也无法将其格式化。

解决办法

from bson import json_util
 
data = json_util.dumps(data)
return HttpResponse(data)

路由配置

app/urls.py(需自建)

import App.views
from django.contrib import admin
from django.urls import path

urlpatterns = [
    path('',App.views.function),
    path……
]

urls.py

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

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

跨域问题解决

https://www.cnblogs.com/majingjie/p/11152052.html

django.core.management.base.SystemCheckError: SystemCheckError: System check identified some issues:

ERRORS:
?: (corsheaders.E014) Origin ‘http://123.56.127.98/' in CORS_ORIGIN_WHITELIST should not have path
?: (corsheaders.E014) Origin ‘http://onestep.wanqqq29.cn/' in CORS_ORIGIN_WHITELIST should not have path