如何将数据库路由器添加到 Django 项目

Question

我正在遵循关于如何在一个 Django 项目中处理多个数据库的说明，来自这里的topics/db/multi-db

我已经创建了所需的两个路由器。它们被保存为 ./database_routers/discourse.py 和 ./database_routers/wordpress.py

./database_routers/discourse.py 的内容是

class DiscourseRouter:
    """
    A router to control all database operations on models in the
    discourse application.
    """
    def db_for_read(self, model, **hints):
        """
        Attempts to read discourse models go to discourse.
        """
        if model._meta.app_label == 'discourse':
            return 'discourse'
        return None

    def db_for_write(self, model, **hints):
        """
        Attempts to write discourse models go to discourse.
        """
        if model._meta.app_label == 'discourse':
            return 'discourse'
        return None

    def allow_relation(self, obj1, obj2, **hints):
        """
        Allow relations if a model in the discourse app is involved.
        """
        if obj1._meta.app_label == 'discourse' or \
           obj2._meta.app_label == 'discourse':
           return True
        return None

    def allow_migrate(self, db, app_label, model_name=None, **hints):
        """
        Make sure the discourse app only appears in the 'discourse'
        database.
        """
        if app_label == 'discourse':
            return db == 'discourse'
        return None

./database_routers/wordpress.py 的内容是

class WordpressRouter:
    """
    A router to control all database operations on models in the
    wordpress application.
    """
    def db_for_read(self, model, **hints):
        """
        Attempts to read wordpress models go to wordpress.
        """
        if model._meta.app_label == 'wordpress':
            return 'wordpress'
        return None

    def db_for_write(self, model, **hints):
        """
        Attempts to write wordpress models go to wordpress.
        """
        if model._meta.app_label == 'wordpress':
            return 'wordpress'
        return None

    def allow_relation(self, obj1, obj2, **hints):
        """
        Allow relations if a model in the wordpress app is involved.
        """
        if obj1._meta.app_label == 'wordpress' or \
           obj2._meta.app_label == 'wordpress':
           return True
        return None

    def allow_migrate(self, db, app_label, model_name=None, **hints):
        """
        Make sure the wordpress app only appears in the 'wordpress'
        database.
        """
        if app_label == 'wordpress':
            return db == 'wordpress'
        return None

我创建了一个空./database_routers/__init__.py文件

我设置的 api/settings 中的数据库路由器设置

DATABASE_ROUTERS = ['database_routers.DiscourseRouter', 'database_routers.WordpressRouter']

当我尝试使用 shell 和 I 查看项目时

 ./manage.py shell_plus

我得到

ImportError: Module "database_routers" does not define a "DiscourseRouter" attribute/class

您如何将数据库路由器添加到 Django 项目，以便 python 识别路径 directory_name.ClassName？

Answer 1

你错过了模块名称。

DATABASE_ROUTERS = [
    'database_routers.discourse.DiscourseRouter', 
    'database_routers.wordpress.WordpressRouter'
]