I totally disagree. Save the whole thing in session after validation and then display all the results on a confirmation page. If the user confirms it, then save each field that was actually answered in a relevant database table.
Summer's idea is open to errors or intentional bad input from the user. There is nothing to prevent them from bookmarking http://www.mysite.com/mycontroller/form2/transaction_id or intentionally changing the transaction_id.
I've built one multi-page form now using summer's idea, another using codeigniter's session class but storing the sessions in a database, and another one saving each page to a database table but using a log in system to track the user. The last option is the most robust, but is a real pain. The session system is best.