django 数据库相关配置

I.读写分离

1.手动分库的写法

配置多个数据库

DATABASES = {

'default': {

'ENGINE': 'django.db.backends.sqlite3',

'NAME': os.path.join(BASE_DIR, 'db.sqlite3'),

},

'db2': {

'ENGINE': 'django.db.backends.sqlite3',

'NAME': os.path.join(BASE_DIR, 'db2.sqlite3'),

},

}

配置之后迁移数据库

python manage.py migrate

视图函数中进行orm操作时,可以指定数据库

# Create your views here.

def index(request, *args):

obj = models.Student.objects.using('deafult').get(pk=3)

obj2 = models.Student.objects.using('db2').create(name='xxx',class='1')

return render(request, 'index.html',{'time':time.time()})

2.自动分库的写法

settings.py中配置

DATABASE_ROUTERS = ['myrouter.Router']

新建一个myrouter.py文件

class Router:

def db_for_read(self, model, **kwargs):

return 'default'

def db_for_write(self, model, **kwargs):

return 'db2'

此时在视图函数中就不用手动指定库名了

II.一主多从的配置

要求一个库中写入,多个库中读取

myrouter.py中

import random

class Router:

"""

一主多从

"""

def db_for_read(self, model, **kwargs):

return random.choice(['db1', 'db2', 'db3']) # 这是自己做的逻辑,还可以加权重

def db_for_write(self, model, **kwargs):

return 'default'

III.分库分表的配置

class Router:

"""

分库分表

app01的操作 default

app02的操作 db2

"""

def db_for_read(self, model, **kwargs):

if model._meta.app_label == 'app01':

return 'default'

elif model._meta.app_label == 'app02':

return 'db2'

def db_for_write(self, model, **kwargs):

if model._meta.app_label == 'app01':

return 'default'

elif model._meta.app_label == 'app02':

return 'db2'