django同一个项目中连接多个数据库
一、场景与思路
同一个项目中需要连接多个数据库。
二、代码
代码中主要是三个部分,settings、models以及自己写的一个类。
1.自己写的文件:database_app_router.py 类名:DatabaseAppsRouter
# database_app_router.py
# -*- coding: utf-8 -*-
from django.conf import settings
DATABASE_MAPPING = settings.DATABASES_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."""
"""将所有读操作指向特定的数据库。"""
if model._meta.app_label in DATABASE_MAPPING:
return DATABASE_MAPPING[model._meta.app_label]
return None
def db_for_write(self, model, **hints):
"""Point all write operations to the specific database."""
"""将所有写操作指向特定的数据库。"""
if model._meta.app_label in DATABASE_MAPPING:
return DATABASE_MAPPING[model._meta.app_label]
return None
def allow_relation(self, obj1, obj2, **hints):
"""Allow any relation between apps that use the same database."""
"""允许使用相同数据库的应用程序之间的任何关系"""
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
else:
return None
def allow_syncdb(self, db, model):
"""Make sure that apps only appear in the related database."""
"""确保这些应用程序只出现在相关的数据库中。"""
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."""
"""确保身份验证应用程序只出现在“authdb”数据库中。"""
if db in DATABASE_MAPPING.values():
return DATABASE_MAPPING.get(app_label) == db
elif app_label in DATABASE_MAPPING:
return False
return None
settings.py文件中修改
# settings.py
DATABASES = {
"default": {
"ENGINE": "django.db.backends.mysql",
"NAME": "integral_wall",
"USER": "root",
"PASSWORD": "123456",
"HOST": "127.0.0.1",
"PORT": "3306",
},
"sdk_51zhuan": {
"ENGINE": "django.db.backends.mysql",
"NAME": "sdk_51zhuan",
"USER": "root",
"PASSWORD": "123456",
"HOST": "127.0.0.1",
"PORT": "3306",
},
}
DATABASES_APPS_MAPPING = {
'integral_wall': 'default',
'sdk_db': 'sdk_51zhuan',
'admin': 'sdk_51zhuan',
'auth': 'sdk_51zhuan',
} DATABASE_ROUTERS = ['integral_wall_manager.database_app_router.DatabaseAppsRouter']
models.py文件修改
# models.py
class SdkApplication(models.Model):
"""
应用程序列表
"""
sdk_type_choices = (
(0, '不合作'),
(1, '一定时间内合作'),
(2, '永久合作'),
)
id = models.AutoField(primary_key=True)
app_id = models.CharField('苹果商店里的APP id', max_length=16, default='')
app_name = models.CharField('应用名称', max_length=64)
bundle_id = models.CharField('包ID,域名倒序', max_length=64, default='')
create_time = models.DateTimeField('创建时间', auto_now_add=True)
class Meta:
app_label = 'sdk_db' # 连接的数据库
db_table = "sdk_application" # 表名
class AdRecord(models.Model):
"""
广告记录
"""
type = models.CharField('操作类型', max_length=16)
action = models.CharField('操作、行为', max_length=16)
create_time = models.DateTimeField('创建时间', auto_now_add=True)
class Meta:
# app_label 不写,使用默认
db_table = "ad_record" # 表名
三、执行
执行的顺序就是大家熟悉的了:
1.python manage.py makemigrations
之后的稍有不同:
2.python manage.py migrate —database=sdk_51zhuan
……
python manage.py migrate(只有默认数据库不为空时才可以这么实用,若为空则是用上面的方法)
其实在这里没有特别的执行顺序,但是我个人建议大家是最后执行migrate(即默认数据库)。另外要注意一点,admin、auth是一定要在一个app里被makemigrations放到一个XXXX_initial.py文件中的,不然你怎么migrate都不会有这些Django自建的表的!
****最后的最后一定要注意:不在一个库里了,没法跨库建立约束关系,放弃外键,老老实实一步步查!****
转载于//www.cnblogs.com/aaron-agu/p/11019226.html
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