如何在Django 1.4中使用DB路由器

本文介绍了如何在Django 1.4中使用DB路由器的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述

我一直在尝试将Django 1.4.3设置为使用多个数据库，但是我一生都无法使其正常运行。我阅读了SO的文档和帖子，并执行了以下操作：

1）在中添加第二个数据库配置settings.py ，如下所示：

DATABASES = {'default'：{ 'ENGINE'：'django.db.backends.sqlite3'，'NAME'：'/tmp/django.db'，'USER'：''， 'PASSWORD'：''，'HOST'：''，'PORT'：''，}，'db1'：{'ENGINE '：'django.db.backends.mysql'，'NAME'：'db1'，'USER'：'fake'，'PASSWORD'：'fake'，'HOST'：'fake.host'，'PORT'：'3306'，}，}

2）创建 routers.py 并定义数据库路由器，如下所示 （注意：根据SO的帖子，如果您在 models.py 中定义一个数据库路由器，则该路由器将无法工作）

class DBRouter（object）： def db_for _read（自我，模型，**提示）：返回'db1' def db_for_write（自我，模型，**提示）：返回'db1' def allow_syncdb（self，db，model）：返回'db1'

3）将以下行添加到 settings.py （注意：根据SO帖子，这些行必须在数据库配置之后

来自django.db导入连接 DATABASE_ROUTERS = ['fakeproject.routers.DBRouter'，]

这是错误的。不要在此处放置django.db导入连接中的 ，因为它会阻止路由器注册

我的症状： 显然，我所有的呼叫都通过默认数据库路由。下面的详细信息：

• 两个DB设置均有效（我可以执行 manage.py indpectdb --database db1 成功

• DATABASE_ROUTERS 设置不会产生任何抱怨（即使我

• 当我尝试通过 manage访问对象时，将错误的路径放置到DB路由器，甚至是非字符串对象） .py shell ，我可以执行 MyModel.objects.all（），但是当我实际尝试对其进行迭代时，会被告知没有这样的表。默认数据库没有该表，但是当我使用 inspectdb

任何帮助都值得赞赏！

解决方案

我发现第3步中的语句

I've been trying to setup Django 1.4.3 to use multiple DBs, but for the life of me I can't make it to work. I read the documentation and posts on SO, and did the following:

1) Add a second DB configuration in settings.py, as follows:

DATABASES = { 'default': { 'ENGINE': 'django.db.backends.sqlite3', 'NAME': '/tmp/django.db', 'USER': '', 'PASSWORD': '', 'HOST': '', 'PORT': '', }, 'db1' : { 'ENGINE': 'django.db.backends.mysql', 'NAME': 'db1', 'USER': 'fake', 'PASSWORD': 'fake', 'HOST': 'fake.host', 'PORT': '3306', }, }

2) Create a routers.py and define a DB router as follows (Note: According to SO posts, if you define a DB router in models.py, the router will not work)

class DBRouter(object): def db_for_read(self, model, **hints): return 'db1' def db_for_write(self, model, **hints): return 'db1' def allow_syncdb(self, db, model): return 'db1'

3) Add the following lines to settings.py (Note: According to SO posts, these lines must be AFTER the DATABASES configurations

from django.db import connections DATABASE_ROUTERS = ['fakeproject.routers.DBRouter',]

This was wrong. Do NOT put from django.db import connections here as it prevents the router to be registered

My symptoms: Apparently, all my calls are routed through the default DB. Details below:

• Both DB settings work (I can perform manage.py indpectdb --database db1 successfully

• DATABASE_ROUTERS setting does not generate any complains (even if I put a wrong path to the DB router, or even a non-string object)

• When I attempt to access my objects via manage.py shell, I can do MyModel.objects.all() but when I actually try to iterate it, I'm told no such table. The default DB does not have that table, but 'db1' clearly has it as I generated the model by using inspectdb on it. As a proof, if I swap the DB configuration between db1 and default, I can access the object without problems.

Any help highly appreciated!

解决方案

I found out that the statement in step 3 "from django.db import connections " was preventing the DB router to be registered. When I removed this statement, the router was registered and stuff started to work as expected.