proc db_test_insert {} {
    set pool "main"
    set db [ns_db gethandle $pool]
    
    set set_id [ns_conn form]
    set user_id   '[ns_set get $set_id user_id]'
    set firstname '[ns_set get $set_id firstname]'
    set surname   '[ns_set get $set_id surname]'
    set email     '[ns_set get $set_id email]'

    set sql "INSERT INTO users(user_id, firstname, surname, email)
             VALUES($user_id, $firstname, $surname, $email)"
    
    ns_db dml $db $sql

    set row [ns_db 0or1row $db "select * from users where user_id = $user_id"]
    if {$row eq ""} {
        set html "Insert failed: $user_id, $firstname, $surname, $email"
    } else {
        set html "Insert success!  -  [ns_set array $row]"
    }

    ns_db releasehandle $db
    
    ns_return 200 text/html $html
}