php ユーザーの削除

<?php # Script 10.2 - delete_user.php
// This page is for deleting a user record.
// This page is accessed through view_users.php.
$page_title = &#39;Delete a User&#39;;
echo &#39;<h1>Delete a User</h1>&#39;;
// Check for a valid user ID, through GET or POST:
if ( (isset($_GET[&#39;id&#39;])) && (is_numeric($_GET[&#39;id&#39;])) ) { // From view_users.php
$id = $_GET[&#39;id&#39;];
} elseif ( (isset($_POST[&#39;id&#39;])) && (is_numeric($_POST[&#39;id&#39;])) ) { // Form submission.
$id = $_POST[&#39;id&#39;];
} else { // No valid ID, kill the script.
echo &#39;<p class="error">This page has been accessed in error.</p>&#39;;
exit();
}
require (&#39;c.php&#39;);
// Check if the form has been submitted:
if ($_SERVER[&#39;REQUEST_METHOD&#39;] == &#39;POST&#39;) {
if ($_POST[&#39;sure&#39;] == &#39;Yes&#39;) { // Delete the record.
// Make the query:
$q = "DELETE FROM user WHERE user_id=$id LIMIT 1";$r = @mysqli_query ($dbc, $q);
if (mysqli_affected_rows($dbc) == 1) { // If it ran OK.
// Print a message:
echo &#39;<p>The user has been deleted.</p>&#39;;} else { // If the query did not run OK.
echo &#39;<p class="error">The user could not be deleted due to a system error.</p>&#39;; // Public message.
echo &#39;<p>&#39; . mysqli_error($dbc) . &#39;<br />Query: &#39; . $q . &#39;</p>&#39;; // Debugging message.
}
} else { // No confirmation of deletion.
echo &#39;<p>The user has NOT been deleted.</p>&#39;;}
} else { // Show the form.
// Retrieve the user&#39;s information:
$q = "SELECT CONCAT(last_name, &#39;, &#39;, first_name) FROM user WHERE user_id=$id";
$r = mysqli_query ($dbc, $q);
if (mysqli_num_rows($r) == 1) { // Valid user ID, show the form.
// Get the user&#39;s information:
$row = mysqli_fetch_array ($r, MYSQLI_NUM);
// Display the record being deleted:
echo "<h3>Name: $row[0]</h3>
Are you sure you want to delete this user?";
// Create the form:
echo &#39;<form action="delete_user.php" method="post">
<input type="radio" name="sure" value="Yes" /> Yes聽
<input type="radio" name="sure" value="No" checked="checked" /> No
<input type="submit" name="submit" value="Submit" />
<input type="hidden" name="id" value="&#39; . $id . &#39;" />
</form>&#39;;
} else { // Not a valid user ID.
echo &#39;<p class="error">This page has been accessed in error.</p>&#39;;
}
} // End of the main submission conditional.
mysqli_close($dbc);
?>