Warum kann ich Daten mit diesem Code nicht löschen?

Question

Ich schrieb ein Notebook mit PHP und XAMPP, irgendwie funktioniert meine Löschfunktion nicht, kann jemand das Problem herausfinden?

admin % global ALL PRIVILEGES Yes  Edit Privileges Edit Privileges 
database-specific ALL PRIVILEGES No Edit Privileges Edit Privileges 
admin localhost global ALL PRIVILEGES Yes  Edit Privileges Edit Privileges 
database-specific ALL PRIVILEGES No Edit Privileges Edit Privileges 
root 127.0.0.1 global ALL PRIVILEGES Yes  Edit Privileges Edit Privileges 
root localhost global ALL PRIVILEGES Yes  Edit Privileges Edit Privileges 

ALTER TABLE `note` CHANGE `id` `id` INT(100) NOT NULL AUTO_INCREMENT , 
CHANGE `topic` `topic` VARCHAR(1000) CHARACTER SET latin1 COLLATE latin1_swedish_ci NOT NULL , 
CHANGE `topicoutline` `topicoutline` VARCHAR(2000) CHARACTER SET latin1 COLLATE latin1_swedish_ci NOT NULL , 
CHANGE `timestamp` `timestamp` TIMESTAMP ON UPDATE CURRENT_TIMESTAMP NOT NULL DEFAULT '0000-00-00 00:00:00' 

<?php 
    $userName = "admin"; 
    $password = "admin"; 
    $hostname = "localhost"; 
    $databaseName = "notebook"; 
    $tableName = "note"; 
    $myDB = mysql_connect("localhost", $userName, $password); 

if ($myDB) { print "Database Connect succeeded<p>"; } 
else { print "Database Connect failed<p>"; die(1);} 

//connect and astart using the database 

$status = mysql_select_db($databaseName, $myDB); 
if ($status) 
{ echo "Select Database $databaseName succeeded<p>"; } 
else 
{ echo "Select Database $databaseName failed<p>";} 

#$result = mysql_query('Select * from note', $myDB); 

#while ($row = mysql_fetch_row($result)) { 

    #echo $row[0] . ", "; #display results 
    #echo $row[1] . ", "; 
    #echo $row[2] . ", "; 
    #echo $row[3] . "<p>"; 
#} 
#mysql_free_result($result); # release memory 
#mysql_close($myDB); 

    function AddTopic() { 
     global $myDB, $this_script; 

     if (isset ($_POST['topic'])) 
     $topic = $_POST['topic']; 
     else 
     return; 

     if (isset ($_POST['topicoutline'])) 
     $topicoutline = $_POST['topicoutline']; 
     else 
     return; 

     if($topic == "" || $topicoutline == "") 
     return; 



     $query = "insert into note (topic, topicoutline, timestamp) values('$topic', '$topicoutline', now());"; 
     $result = mysql_query($query, $myDB); 

     if (!$result) mysql_error($myDB); 
     else header("Location: $this_script"); #redirect to Show all 
     } 

    function ShowAll() { 
     global $myDB; 
     $query="Select * from note;"; 
     $result = mysql_query($query, $myDB); 
    while ($row = mysql_fetch_object($result)) { 
    echo $row->id . "<br>"; 
    echo $row->topic . "<br>"; 
    echo $row->topicoutline . "<br>"; 
    echo $row->timestamp . "<p>"; 
    }  

    mysql_free_result($result); 
    } 

    function td($item){ 
    return "<td>$item</td>\n"; 
    } 

    function linktodelete($url, $prompt){ 

    return "<a href = '$url'>$prompt</a>"; 

    } 

    function FrontPage() { 

     global $myDB, $this_script; 
     deleteTopic(); 
     AddTopic(); 

    if (isset($_REQUEST['findthis'])) 
    $where = $_REQUEST['findthis']; 
    else $where = ''; 
    $query = 'Select * from note'; 
    if ($where) 
    $query = $query . " where topic like '%$where%' or topicoutline like '%$where%'"; 
    $query = $query .";" ; 
    $result = mysql_query($query, $myDB); 
    print "<table border='1' bgcolor='#AADDFF' width='80%'>\n"; 

    print "<tr><td>id</td> <td>topic</td> <td>topicoutline</td> <td>timestamp</td></tr> \n"; 

    while ($row =mysql_fetch_object($result)) { 
    $id = $row->id; 
    print "<tr>"; 

    print td($row->id). td($row->topic). td($row->topicoutline). td($row->timestamp). td(linktodelete($this_script . "?cmd=del&id=$id","Delete")); 
    print "</tr>\n"; 

    } 

    print "<table>\n"; 
    mysql_free_result($result); 

    print DisplayFindForm(); 
    print DisplayNameAdditionForm(); 
    } 
    //showAll(); 

    function deleteTopic() { 
    global $myDB, $this_script; 
    if (isset($_REQUEST['$id'])) 
    $id = $_REQUEST['id']; 
    else 
    $id = ''; 
    $query = "delete from note where id='$id';"; 
    $result = mysql_query($query, $myDB); 
    if (!$result) mysql_error($myDB); 
    else header("Location: $this_script"); 
    } 

    function DisplayNameAdditionForm() { 
    global $this_script; 
    print " 
    <hr> 
    <form method='POST' action='$this_script'> 
    <input type='hidden' name='cmd' value='add'> 
    topic <input type='text' name='topic' size='100'> 
    topicoutline <input type='text' name='topicoutline' size='100'> 
    <input type='submit' value=' Add ' name='B1'> 
    </form> 
    "; 
    } 


    function DisplayFindForm() { 
    global $this_script; 
    print " 
    <hr> 
    <form method='POST' action='$this_script'> 
    <input type='hidden' name = 'cmd' value='find'> 
    <input type='text' name = 'findthis' size='20'> 
    <input type='submit' value=' Find name ' name='B1'> 
    </form> 
    "; 
    } 

    FrontPage(); 

    ?> 

Answer 1

if (isset($_REQUEST['$id'])) 
        ^

Das Dollarzeichen muss entfernt werden.