get the id of the corresponding uploaded file from the databse table

i have four upload controls linked to only one upload button means i can upload four files in one go,the moment i upload files dere corresponding IDs are generated in the sql database table. my question is how can i grab those IDs coz i need to pass those IDs to next page through session..
have a look on my upload button click event
protected void Button1_Click(object sender, EventArgs e)
{
string emailid = Membership.GetUser().Email;
   
   
FileUpload[] fl = new FileUpload[4] { FileUpload1, FileUpload2, FileUpload3, FileUpload4 };
string[] cm = new string[4] { TextBox2.Text, TextBox3.Text, TextBox4.Text, TextBox5.Text };
   

for (int i = 0; i < 4; i++)
{
if (fl[i].PostedFile.ContentLength != 0)
{
   
string folder = Server.MapP ...