need Help in paypal integration ( Urgent )

[eluser]Ritesh Thumar[/eluser]
i have integrate paypal payment module in my code igniter site at registration process.
it's working as following.
1) first user will fill the form with payable amount
2) than he will redirect to paypal.
3) after that he need to enter paypal username and password and after successfully login the amount which he was filled in form will withdraw from his account .
4) after that paypal will give option :- go to the site

now my problem is that how can i know that which person has made payment for his new account,.. at same time many people will access that process so how can i identify the person that who has made the how much payment...

is paypal will give any info that from you site this user has made the payment...for example username or userid from my side so i can know that this the person who made the payment.


rply as soon as poss..

Thank You

[eluser]Iván Argulo[/eluser]
When you redirect to PayPal you must provide a param called "Transaction ID". This must be unique, and it's returned by PayPal on the response. So you can store all the payment data in your database (inclusive this Transaction ID) and then, when receiving the PayPal confirmation, update your database according to the Transaction ID, returned by PayPal.

Hope it helps.

[eluser]Unknown[/eluser]
thanks the information was very informative. this is what i am looking for