I want to know what are the conventions for columns like
password when your application supports login with a third party, like login with facebook for instance.
Given the fact that when you Log with a 3rd party, you don't really need to specify a
username, you'll just specify the 3rd party
user id, in database design, you can expect either a
blank field or a
Since usernames are
UNIQUE, I'm guessing going for
nullable is the way to go, since it allows multiple null columns.
The real issue is that the user needs to specify either a username OR a 3rd party id. Which means both columns can be null, but not at the same time
So what's the convention for handling this design pattern?