欢迎来到代码驿站!

Python代码

当前位置:首页 > 软件编程 > Python代码

django使用多个数据库的方法实例

时间:2022-03-10 20:57:21|栏目:Python代码|点击:

通过官方文档https://docs.djangoproject.com/zh-hans/3.1/topics/db/multi-db/和csdnhttps://blog.csdn.net/songfreeman/article/details/70229839的这两篇文章可以进行多数据库的设置。但是设置后可能会出现问题,由于我连接的数据库是通过inspactdb的方法得到的model。于是在migrate的时候出现了问题,会提示 1146, “Table xxx doesn't exist” 。后来发现问题可能出在路由表上,按照DATABASE_APPS_MAPPING映射之后,django默认的表如果要写入可能会找不到数据库。而源代码里的映射关系并不包含新加入的app,例如grappelli等。

DATABASE_APPS_MAPPING = {
# example:
# 'app_name':'database_name',
# 'admin': 'default',
# 'users': 'default', #django
'basic_estate': 'basic_estate',
'footstone': 'footstone',
'mall': 'hsmall',
'iot_biz': 'iot_biz',
'mall': 'mall',
'hsuser': 'hsuser',
}

如果要解决这个问题可以修改router代码,在映射关系内找不到对应的数据库的情况下返回默认数据库连接即可:

# -*- coding: utf-8 -*-
"""
@author: obaby
@license: (C) Copyright 2013-2020, obaby@mars.
@contact: root@obaby.org.cn
@link: http://www.obaby.org.cn
  http://www.h4ck.org.cn
  http://www.findu.co
@file: atabase_router.py.py
@time: 2021/2/26 9:07
@desc:
"""
from django.conf import settings
 
DATABASE_MAPPING = settings.DATABASE_APPS_MAPPING
 
 
class DatabaseAppsRouter(object):
 """
 A router to control all database operations on models for different
 databases.
 
 In case an app is not set in settings.DATABASE_APPS_MAPPING, the router
 will fallback to the `default` database.
 
 Settings example:
 
 DATABASE_APPS_MAPPING = {'app1': 'db1', 'app2': 'db2'}
 """
 
 def db_for_read(self, model, **hints):
  """"Point all read operations to the specific database."""
  if model._meta.app_label in DATABASE_MAPPING:
   return DATABASE_MAPPING[model._meta.app_label]
  return 'default'
 
 def db_for_write(self, model, **hints):
  """Point all write operations to the specific database."""
  if model._meta.app_label in DATABASE_MAPPING:
   return DATABASE_MAPPING[model._meta.app_label]
  return 'default'
 
 def allow_relation(self, obj1, obj2, **hints):
  """Allow any relation between apps that use the same database."""
  db_obj1 = DATABASE_MAPPING.get(obj1._meta.app_label)
  db_obj2 = DATABASE_MAPPING.get(obj2._meta.app_label)
  if db_obj1 and db_obj2:
   if db_obj1 == db_obj2:
    return True
   else:
    return False
  return None
 
 def allow_syncdb(self, db, model):
  """Make sure that apps only appear in the related database."""
 
  if db in DATABASE_MAPPING.values():
   return DATABASE_MAPPING.get(model._meta.app_label) == db
  elif model._meta.app_label in DATABASE_MAPPING:
   return False
  return None
 
 def allow_migrate(self, db, app_label, model=None, **hints):
  """
  Make sure the auth app only appears in the 'auth_db'
  database.
  """
  if db in DATABASE_MAPPING.values():
   return DATABASE_MAPPING.get(app_label) == db
  elif app_label in DATABASE_MAPPING:
   return False
  return None

这样django系统所需的数据库就能正常创建了:

总结

上一篇:pandas数据分组groupby()和统计函数agg()的使用

栏    目:Python代码

下一篇:Python日志无延迟实时写入的示例

本文标题:django使用多个数据库的方法实例

本文地址:http://www.codeinn.net/misctech/195792.html

推荐教程

广告投放 | 联系我们 | 版权申明

重要申明:本站所有的文章、图片、评论等,均由网友发表或上传并维护或收集自网络,属个人行为,与本站立场无关。

如果侵犯了您的权利,请与我们联系,我们将在24小时内进行处理、任何非本站因素导致的法律后果,本站均不负任何责任。

联系QQ:914707363 | 邮箱:codeinn#126.com(#换成@)

Copyright © 2020 代码驿站 版权所有