Perl sessions OR cookie handling OR something else
 

Hi,
I'm developing a website where some data, input by the user has to be put into a database, based on certain conditions - i.e. when they input their name and the data, if their name is already in the database, then a new line with their name will NOT be created in the database, otherwise it will (this is a MySQL database). For this, when they post the data, a page will be shown to them saying "Same person" or "Not same person". My question is - how to program this, that is, I would like the data that they've posted to be held *on the client side*, and if they click "Not same person", then that data will be posted along with their name.
I would like to do this using cookies, which is why I've been Googling lots of pages on Perl sessions (which I *think* does cookie handling), but I'm totally new to all this - could someone help me as to how the data would be held on the client side between two different programs, ie. submit.cgi and notsame.cgi .
Thanks a lot.