Projections

The fetch join from the previous lesson brought the staff page down to one statement for 30 bookings. That statement selected 14 columns for every booking, and the page used 2 of them: the seat label and the customer's email. Among the other 12 was each customer's password hash, a value the page never shows and that should not leave the database without a reason.

The same query also placed 62 entities in the persistence context: 30 bookings, 30 seats, and 2 customers