快捷導(dǎo)航

django使用多個(gè)數(shù)據(jù)庫的方法實(shí)例

更新時(shí)間：2021年03月04日 11:54:00 作者：obaby@mars

這篇文章主要給大家介紹了關(guān)于django使用多個(gè)數(shù)據(jù)庫的相關(guān)資料，文中通過示例代碼介紹的非常詳細(xì)，對(duì)大家的學(xué)習(xí)或者工作具有一定的參考學(xué)習(xí)價(jià)值，需要的朋友們下面隨著小編來一起學(xué)習(xí)學(xué)習(xí)吧

通過官方文檔https://docs.djangoproject.com/zh-hans/3.1/topics/db/multi-db/和csdnhttps://blog.csdn.net/songfreeman/article/details/70229839的這兩篇文章可以進(jìn)行多數(shù)據(jù)庫的設(shè)置。但是設(shè)置后可能會(huì)出現(xiàn)問題，由于我連接的數(shù)據(jù)庫是通過inspactdb的方法得到的model。于是在migrate的時(shí)候出現(xiàn)了問題，會(huì)提示 1146, “Table xxx doesn't exist” 。后來發(fā)現(xiàn)問題可能出在路由表上，按照DATABASE_APPS_MAPPING映射之后，django默認(rèn)的表如果要寫入可能會(huì)找不到數(shù)據(jù)庫。而源代碼里的映射關(guān)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',
}

如果要解決這個(gè)問題可以修改router代碼，在映射關(guān)系內(nèi)找不到對(duì)應(yīng)的數(shù)據(jù)庫的情況下返回默認(rèn)數(shù)據(jù)庫連接即可：

# -*- 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

這樣django系統(tǒng)所需的數(shù)據(jù)庫就能正常創(chuàng)建了：