django多数据库迁移：如何防止在每个数据库中创建django默认表答案

【问题标题】：django multiple database migrations:how to prevent to create django default tables in each databasedjango多数据库迁移：如何防止在每个数据库中创建django默认表
【发布时间】：2021-07-09 20:19:59
【问题描述】：

我有多个数据库，每个应用程序通过路由器类绑定到一个数据库

class DatabaseRouter:
    """
    A router to control all database operations on models in the
    auth and contenttypes applications.
    """
    lawyer_app_labels = {'lawyer'}
    court_app_labels = {'court'}
    type_app_labels = {'type'}

    def db_for_read(self, model, **hints):
        """
        Attempts to read auth and contenttypes models go to auth_db.
        """
        if model._meta.app_label in self.lawyer_app_labels:
            return 'lawyer_db'
        if model._meta.app_label in self.court_app_labels:
            return 'court_db'
        if model._meta.app_label in self.type_app_labels:
            return 'type_db'
        return None

    def db_for_write(self, model, **hints):
        """
        Attempts to write auth and contenttypes models go to auth_db.
        """
        if model._meta.app_label in self.lawyer_app_labels:
            return 'lawyer_db'
        if model._meta.app_label in self.court_app_labels:
            return 'court_db'
        if model._meta.app_label in self.type_app_labels:
            return 'type_db'
        return None


    def allow_relation(self, obj1, obj2, **hints):
        """
        Allow relations if a model in the auth or contenttypes apps is
        involved.
        """
        if (
                obj1._meta.app_label in self.lawyer_app_labels or
                obj2._meta.app_label in self.lawyer_app_labels
        ):
            return True

        if (
                obj1._meta.app_label in self.court_app_labels or
                obj2._meta.app_label in self.court_app_labels
        ):
            return True

        if (
                obj1._meta.app_label in self.type_app_labels or
                obj2._meta.app_label in self.type_app_labels
        ):
            return True

        return None


    def allow_migrate(self, db, app_label, model_name=None, **hints):
        """
        Make sure the auth and contenttypes apps only appear in the
        'auth_db' database.
        """
        if app_label in self.lawyer_app_labels:
            return db == 'lawyer_db'
        if app_label in self.court_app_labels:
            return db == 'court_db'
        if app_label in self.type_app_labels:
            return db == 'type_db'
        return None

每次我尝试使用 --database 标志进行迁移时，它都会成功创建应用程序表，但在所有应用程序 django 中都会创建默认表，例如会话和内容类型我怎样才能防止这种情况我有 4 个数据库在正确设置设置 django 默认表的默认值和其他 3 人各 1 个应用程序

【问题讨论】：

标签： python django orm

【解决方案1】：

我终于找到了自己的答案 { 'admin', 'auth', 'contenttypes', 'sessions' } 这是 django 的默认应用程序的名称所以我把它们包括在

base_app_labels = { 'admin', 'auth',  'contenttypes', 'sessions' }
def allow_migrate(self, db, app_label, model_name=None, **hints):
    if app_label in self.base_app_labels:
        return db == 'default'

如果我的数据库名称与此应用名称中的默认值不匹配，这会阻止它迁移

【讨论】：