Problem with function odbc_fetch_array.

[D4vis]

Hi,
I have a problem with this code:

     $conn = connect();
     $query = 'select * from Dipendente where Ruolo=\'Docente\'';
     $ris = odbc_exec($conn, $query);
      while ($dati = odbc_fetch_array($ris))
      {
           echo "check";
           echo $dati['Id'];
      }

The query and the while are ok but echo $dati['Id'] don't write nothing.
P.S. The fild "Id" is correct.

Thanks in advance;
D4vis.