Esto te puede servir
function modificar( )
{
$SqlUpdate="update USER_IMED.DOLLAR_LOGIN SET END_DATE=sysdate where ID = (select max(ID) from USER_IMED.DOLLAR_LOGIN WHERE ID_USER=$_REQUEST[no])";
echo "<pre>$SqlUpdate</pre>";
$sth = oci_parse ($GLOBALS["dbh"],$SqlUpdate);
if (oci_execute($sth, OCI_DEFAULT)) {
oci_commit($GLOBALS[dbh]);
} else {
$erra = oci_error($sth);
save_sql_debug_data($SqlUpdate, "ERROR: ${erra['code']} ${erra['message']}");
echo "<!-- ERROR: ${erra['code']} ${erra['message']} -->";
}
}