Google App Engine:修改 1000 个实体 [英] Google App Engine: Modifying 1000 entities

问题描述

我有大约 1000 个这样的用户帐户实体:

I have about 1000 user account entities like this:

class UserAccount(ndb.Model):
    email = ndb.StringProperty()

其中一些电子邮件值包含大写字母，例如 [e-mail].我想从所有 UserAccount 实体中选择所有 email 值并应用 python 的 email.lower().我怎样才能有效地做到这一点，最重要的是，没有错误?

Some of these email values contain uppercase letters like [e-mail]. I want to select all the email values from all UserAccount entities and apply python's email.lower(). How can I do this efficiently, and most importantly, without errors?

注意:电子邮件值对于登录很重要，所以我不能把它搞砸.有没有办法备份这些数据，以防万一我犯了错误?

Note: The email values are important for login, so I cannot afford to mess this up. Is there a way to backup this data in case of the event that I do make a mistake?

谢谢.

推荐答案

是的，当然.即使数据存储管理是一项实验性功能，我们也可以在不编码的情况下备份和恢复数据.按照备份流程的说明进行操作:备份数据.要处理您的数据，最有效的方法是使用 MapReduce 库.

Yes, off course. Even if Datastore Administration is an experimental feature we can backup and restore data without coding. Follow this instruction for the backup flow: Backing up data. To processing your data instead, the most efficient way is to use the MapReduce library.

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