多数据库操作

model。py

from django.db import models

class UserType(models.Model):
    title = models.CharField(max_length=32)

class UserInfo(models.Model):
    name = models.CharField(max_length=64)
    email = models.CharField(max_length=64)
    ut = models.ForeignKey(to='UserType')

命令

python3 manage.py makemigrations

# 指定到db1 数据库里面生成表结构
python3 manage.py migrate app01 --database=db1

方式一：手动

view。py

from django.shortcuts import render,HttpResponse
from app01 import models
def index(request):

    models.UserType.objects.using('db1').create(title='普通用户')
　　# 手动指定去某个数据库取数据
    result = models.UserType.objects.all().using('db1')
    print(result)

    return HttpResponse('...')

注意：

  .using() 是queryset的方法，所以放在后面 

 
  models.UserType.objects   取出来是一个queryset对象 
 
自动：添加配置文件 （读写分离）
 
  class Router1:
　　#  指定到某个数据库取数据
    def db_for_read(self, model, **hints):
        """
        Attempts to read auth models go to auth_db.
        """
        if model._meta.model_name == 'usertype':
            return 'db1'
        else:
            return 'default'
　　　# 指定到某个数据库存数据
    def db_for_write(self, model, **hints):
        """
        Attempts to write auth models go to auth_db.
        """
        return 'default' 
 
再写上配置
 
  DATABASES = {
    'default': {
        'ENGINE': 'django.db.backends.sqlite3',
        'NAME': os.path.join(BASE_DIR, 'db.sqlite3'),
    },
    'db1': {
        'ENGINE': 'django.db.backends.sqlite3',
        'NAME': os.path.join(BASE_DIR, 'db.sqlite3'),
    }
}
DATABASE_ROUTERS = ['db_router.Router1',] 
 

   精进粒度 
 

    读用户类型表去db1， 读用户表去default 
  
 
    class Router1:
    def allow_migrate(self, db, app_label, model_name=None, **hints):
        """
        All non-auth models end up in this pool.
        """
　　　　　# 对数据库迁移也做了约束
        if db=='db1' and app_label == 'app02':
            return True
        elif db == 'default' and app_label == 'app01':
            return True
        else:
            return False

    def db_for_read(self, model, **hints):
        """
        Attempts to read auth models go to auth_db.
        """
        if model._meta.app_label == 'app01':
            return 'default'
        else:
            return 'db1'

    def db_for_write(self, model, **hints):
        """
        Attempts to write auth models go to auth_db.
        """
        if model._meta.app_label == 'app01':
            return 'default'
        else:
            return 'db1' 
   

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