Django项目连接多个数据库配置

1、设置数据库连接

pip install PyMySQL

2、在项目同名目录myproject/myproject下的__init__.py添加以下代码

import pymysql
pymysql.install_as_MySQLdb()

3、修改settings.py中默认的数据库 default

DATABASES = {
    'default': {
        'ENGINE': 'django.db.backends.mysql', #数据库引擎
          'NAME': 'pythondms',                       #数据库名
          'USER': 'root',                       #用户名
          'PASSWORD': '',                   #密码
          'HOST': '36.103.245.29',                           #数据库主机，默认为localhost
          'PORT': '3306',                           #数据库端口，MySQL默认为3306
          'OPTIONS': {
             'autocommit': True,
         }
    }
}

4、多数据库连接配置

#数据库配置
DATABASES = {
   'default': {
          'ENGINE': 'django.db.backends.mysql', #数据库引擎
          'NAME': 'pythondms',                       #数据库名
          'USER': 'root',                       #用户名
          'PASSWORD': '',                   #密码
          'HOST': '36.103.245.29',                           #数据库主机，默认为localhost
          'PORT': '3306',                           #数据库端口，MySQL默认为3306
          'OPTIONS': {
             'autocommit': True,
         }
    },
    'default1': {
          'ENGINE': 'django.db.backends.mysql', #数据库引擎
          'NAME': 'pythondms',                       #数据库名
          'USER': 'root',                       #用户名
          'PASSWORD': '',                   #密码
          'HOST': '39.107.35.95',                           #数据库主机，默认为localhost
          'PORT': '3306',                           #数据库端口，MySQL默认为3306
          'OPTIONS': {
             'autocommit': True,
         }
    }
}
DATABASE_ROUTERS = ['dms.database_router.DatabaseAppsRouter']
DATABASE_APPS_MAPPING = {
    'userctrl': 'default',
    'app02': 'default1',
}

这里配置了一个数据库路由dms.database_router.DatabaseAppsRouter，然后对指定app指定了数据库，'userctrl': 'default', 'app02': 'default',。下面我们需要在唉项目同名目录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 = {'app1': 'db1', 'app2': 'db2'}
    """

    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
            

这样我们就实现了不同app使用不同的数据库了，我们可以使用python manage.py migrate --database=mysql02命令来实现数据库同步（创建表）