dynamic forms

hey everyone, I have this select form which get filled dynamically with all my tables in my database. It depends on which one I choose from the drop down menu, that clicking submit it displays the right table.. now, I need to have a form on the page that would let me insert new records. Of course I don't want to make a form for each table, so I would like to change the entries and values of the insert form in relation to the table I choose from the drop down form above mentioned. Of course the "id" and "created" are NULL because they should get filled automatically. thanks for your help. mas