oci_commit always returns true even when the transaction fails.

Hi there.

Why oci_commit function always returns true even when the transaction fails.
I just copied the code in the php manual [Example 1636. oci_commit() example],
and runned it, the situation is as follows:

* The statements do commit at the moment when oci_commit executes.
* But some statements are committed to oracle successfully, when some fails.
  I think it cannot be called a transaction, and I did used
OCI_DEFAULT in the oci_execute function.

Code:
<?php
$conn = oci_connect('scott', 'tiger');
$stmt = oci_parse($conn, "INSERT INTO employees (name, surname) VALUES
('Maxim', 'Maletsky')");
oci_execute($stmt, OCI_DEFAULT);
$committed = oci_commit($conn);

if (!$committed) {
    $error = oci_error($conn);
    echo 'Commit failed. Oracle reports: ' . $error['message'];
}
?>
$committed is always true, whenever $stmt executes successfully or fails.
I use PHP5.2.12, apache_2.0.63-win32-x86-openssl-0.9.7m.msi, windows
xp, Oracle10.1
and oci8 1.2.5.

thanks.

-- paravoice