I have about 1000 user account entities like this:

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

Some of these email values contain uppercase letters like [email protected]. 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?

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?

Thank you.

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.