<?php

echo "<h1>Edit guestbook</h1>";

//Database info code here...

//FORM VARIABLES

$displayID = trim($_POST['idNo']);
if(!$displayID)
 echo "<h3>Error: No Message ID submitted, please go <a href=edit.php>back</a> and enter a value.</h3>";

$displayName = $_POST['newName'];
if($displayName == "")
 $displayName = NULL;


$displayMessage = $_POST['newMessage'];
if(!$displayMessage)
 echo "<h3>Error: No Message submitted, please go <a href=edit.php>back</a> and enter a message.</h3>";

//Connect to database code here...

#################################################

//UPDATE OLD MESSAGE
$query = " UPDATE messages SET NAME = '$displayName', MESSAGE = '$displayMessage' WHERE ID = '$displayID'";
$result = mysql_query($query);

#################################################

//DISPLAY NEW MESSAGE
$message = @mysql_query("SELECT * FROM `messages` WHERE `ID` =".$displayID);
if(!$message)
 echo "Error: Query is invalid.";

$result = mysql_fetch_array($message);

echo "<strong>Name:</strong> <br/>";
echo $result['NAME']."<br/>";
echo "<strong>Message:</strong> <br/>";
echo $result['MESSAGE']."<br/><br/>";

################################################

echo "Guestbook updated.<br/>";

?>

if ( is_set( $_POST[ "newName" ]))
{
  $displayName = $_POST[ "newName" ];
  // add quotes here
  $displayName = "'$displayName'";
} // otherwise $displayName is not set ie is NULL
 
//  ...
//UPDATE OLD MESSAGE
// don't insert quotes in $displayName here
// because it is either NULL or a string with quotes already
$query = " UPDATE messages SET NAME = $displayName, MESSAGE = '$displayMessage' WHERE ID = '$displayID'";
$result = mysql_query($query);