Transaction to DB in session

HI

I have few forms with respect to their database table,as it is working
fine in normal flow

but what if user enters few forms and clicks back button in the
browser,is there a way to handle it

2)what if i need to enter all the form data once to their respective
model at end of all form

is their a way to handle this two…

can u help me out in finishing my application

thanx