Django读写分离

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'),
    },
}

迁移 migrate --databse db2

读写分离

手动：

# 写入数据库 use using
models.Student.objects.using('db2').create(name='xxxx')

# 读取数据库
ret = models.Student.objects.using('default').all()


# 读取数据库
ret = models.Student.objects.using('default').all()


for i in ret:
    i.name = 'wl'
    i.save(using='default')

自动配置

在项目中创建router文件:app01-> router

class Router:
    def db_for_read(self, model, **kwargs):
        return 'default'

    def db_for_write(self, model, **kwargs):
        return 'db2'

settings

DATABASE_ROUTERS = ['app01.router.Router']

一主多从

写入一个数据中，从多个数据库读取

# 一主多从
import random


class Router:
    def db_for_read(self, model, **kwargs):
        return random.choice(['db1', 'db2', 'db3'])

    def db_for_write(self, model, **kwargs):
        return 'default'

分库分表

app01的表放在db1

app02的表放在db2

# 分库分表

class Router:
    def db_for_read(self, model, **kwargs):
        label = model._meta.app_label

        if label == 'app01':
            return 'db1'
        elif label == 'app02':
            return 'db2'

    def db_for_write(self, model, **kwargs):
        label = model._meta.app_label

        if label == 'app01':
            return 'db1'
        elif label == 'app02':
            return 'db2'

model

model._meta.app_label   app名称
model._meta.model_name    model名称