update a record in database

actually i have created 3 dynamic pages where there are some input fields to get a data from our site members which are already signed up in our site and the purpose for using dynamic pages is when user wants to overwrite any team member’s data from these 3 dynamic pages can easily achieve their updates.
After updating the data… the data should be overwrite in database please help how do i overwrite the data with old data it’s urgent.