Using the Analysis Field in Alto

We currently use the Analysis field to identify the notification method (email or post) for our borrowers. Up until now, we've registered all of our students individually at the beginning of each academic year by asking them which notification method they prefer, as well as some other details. However, this year we're moving to a new model based around self-service, and need to ensure that access to the machines is available from the point of the student's arrival.

So, we have our usual borrower download, but I need to default all borrowers who don't currently have a notification preference to email. I don't think I can do this through the import process as Analysis isn't an available field, and I can't work out the SQL to do something like this.

Does anyone have any ideas?