Django之连接多个数据库的相关配置
01-修改django默认的数据库
# settings.py DATABASES = { 'default': { 'ENGINE': 'django.db.backends.mysql', 'NAME': 'mysql01', #连接的数据库名 'PORT': '3306', 'HOST': 'localhost', 'USER': 'root', 'PASSWORD': '123456', } }
# 修改项目同名目录下的__init__.py文件 import pymysql pymysql.install_as_MySQLdb()
02-配置多数据库连接
# Django 要求default 数据库必须定义,但是如果不会用到,其参数字典可以保留为空。若要这样做,你必须为你的所有的应用的模型建立DATABASE_ROUTERS,包括正在使用的contrib 中的应用和第三方应用。 'default': {},
DATABASES = { 'default': { 'ENGINE': 'django.db.backends.mysql', 'NAME': 'mysql01', #连接的数据库名 'HOST': 'localhost', 'PORT': '3306', 'USER': 'root', 'PASSWORD': '123456', }, 'db02': { 'ENGINE': 'django.db.backends.mysql', 'NAME': 'db02', #连接的数据库名 'HOST': 'localhost', 'PORT': '3306', 'USER': 'root', 'PASSWORD': '123456', } } DATABASE_ROUTERS = ['项目名.database_router.DatabaseAppsRouter'] DATABASE_APPS_MAPPING = { 'app01': 'default', 'app02': 'db02', }
03-实现数据库路由
# 下面我们需要在项目同名目录myproject/myproject下新建一个database_router.py来实现数据库路由
# database_router.py 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 = {'app01': 'default', 'app02': 'db02'} """ 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 None 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 None 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 # for Django 1.4 - Django 1.6 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 # Django 1.7 - Django 1.11 def allow_migrate(self, db, app_label, model_name=None, **hints): print(db, app_label, model_name, hints) if db in DATABASE_MAPPING.values(): return DATABASE_MAPPING.get(app_label) == db elif app_label in DATABASE_MAPPING: return False return None
04-为每个app的model分别指定所需要连接的数据库
# 编辑app01下的models.py: class Book(models.Model): #该model使用default数据库 name=models.CharField(max_length=32,primary_key=True,unique=True) def __str__(self): return self.name class Meta: #app_label = 'app01' #由于该model连接default数据库,所以在此无需指定 ordering = ['name'] db_table = 'book' # 指定生成数据库的表名称
# 编辑app02下的models.py: class Author(models.Model): name=models.CharField(max_length=32,primary_key=True,unique=True) age = models.CharFieid() def __str__(self): return self.name class Meta: app_label = 'app02' #定义该model的app_label ordering = ['name'] db_table = 'authoe' # 指定生成数据库的表名称
05-同步数据库
# 同步default节点数据库,只运行不带 --database参数的命令,不对其他数据库进行同步 python manage.py makemigrations python manage.py migrate
# 同步db02节点数据库: python manage.py makemigrations python manage.py migrate --database=db02