在 Django 中使用多个数据库执行迁移答案

【问题标题】：Performing migrations with multiple databases in Django在 Django 中使用多个数据库执行迁移
【发布时间】：2017-07-06 12:23:20
【问题描述】：

我的项目中有 2 个数据库，其中包含多个应用程序。除了一个应用程序之外的所有应用程序都使用默认数据库，另一个应用程序有一个单独的数据库。在我运行 makemigrations 和 ./manage.py migrate --database=separate_db_name 之后，我仍然有未应用的迁移等待默认数据库。

问题是我如何才能使此迁移仅对我的单独应用程序可见，而不是其他应用程序（使用默认数据库）。谢谢

这是我的路由器

class S3DatabaseRouter(object):
"""
Determine how to route calls for s3web_upload_dev database
"""

def db_for_read(self, model, **hints):
    """
    Attempts to read s3web_upload models to go to s3web_upload_dev
    """
    if model._meta.app_label == 's3web_upload':
        return 's3web_upload_dev'
    return None

def db_for_write(self, model, **hints):
    """
    Attempts to write s3web_upload models to go to s3web_upload_dev
    """
    if model._meta.app_label == 's3web_upload':
        return 's3web_upload_dev'
    return None

def allow_migrate(self, db, app_label, model_name=None, **hints):
    """
    Make sure the s3web_upload app only appears in the 's3web_upload_dev' database
    """
    if app_label == 's3web_upload':
        return db == 's3web_upload_dev'
    return None

【问题讨论】：

标签： python django postgresql

【解决方案1】：

对于使用默认数据库的应用程序也需要在路由器类中进行路由，试试下面的代码它应该可以工作。

class S3DatabaseRouter(object):
    """
Determine how to route calls for s3web_upload_dev database
"""
def db_for_read(self, model, **hints):
    """
    Attempts to read s3web_upload models to go to s3web_upload_dev
    """
    if model._meta.app_label == 's3web_upload':
        return 's3web_upload_dev'
    if app_label == 'default': # if you using custome applable use it instead of 'default'
        return 'default' # it should be the db name from settings file
    return None

def db_for_write(self, model, **hints):
    """
    Attempts to write s3web_upload models to go to s3web_upload_dev
    """
    if model._meta.app_label == 's3web_upload':
        return 's3web_upload_dev'
    if app_label == 'default':
        return 'default'
    return None

def allow_migrate(self, db, app_label, model_name=None, **hints):
    """
    Make sure the s3web_upload app only appears in the 's3web_upload_dev' database
    """
    if app_label == 's3web_upload':
        return db == 's3web_upload_dev'

    if app_label == 'default':
        return db == 'default'
    return None

【讨论】：