Django 多数据库联用

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每个app都可以单独设置一个数据库

settings.py中有数据库的相关设置，有一个默认的数据库 default,我们可以再加一些其它的，比如：

# Database# https://docs.djangoproject.com/en/1.8/ref/settings/#databasesDATABASES = {    'default': {        'ENGINE': 'django.db.backends.sqlite3',        'NAME': os.path.join(BASE_DIR, 'db.sqlite3'),    },    'db1': {        'ENGINE': 'django.db.backends.postgresql_psycopg2',        'NAME': 'dbname1',        'USER': 'your_db_user_name',        'PASSWORD': 'yourpassword',        "HOST": "localhost",    },    'db2': {        'ENGINE': 'django.db.backends.postgresql_psycopg2',        'NAME': 'dbname2',        'USER': 'your_db_user_name',        'PASSWORD': 'yourpassword',        "HOST": "localhost",    },} # use multi-database in django# add by WeizhongTuDATABASE_ROUTERS = ['project_name.database_router.DatabaseAppsRouter']DATABASE_APPS_MAPPING = {    # example:    #'app_name':'database_name',    'app1': 'db1',    'app2': 'db2',}

在project_name文件夹中存放 database_router.py 文件，内容如下：

# -*- coding: utf-8 -*-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

这样就实现了指定的 app 使用指定的数据库了,当然你也可以多个sqlite3一起使用，相当于可以给每个app都可以单独设置一个数据库！如果不设置或者没有设置的app就会自动使用默认的数据库。

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