通過PHP從數據庫刪除條目選擇表單 - 不刪除條目

Question

我想從我的數據庫中刪除一個條目使用HTML表單。但是，提交時，條目不會從數據庫中刪除，也不會顯示錯誤代碼來說明原因。

有人可能會讓我知道，如果我從我的代碼中丟失了某些東西，以防萬一我已經過分看了一些東西？

謝謝。

<form method="post" action="./removeBook.inc.php"> 
<select name="books"> 
<option>Please select the Book you wish to delete:</option> 
<?php 
try { 
    $dsn = "mysql:host=csdm-mysql;dbname=db1001550_book_management"; 
    $username = "1001550"; 
    $password = "1001550"; 
    // try connecting to the database 
    $con = new PDO($dsn, $username, $password); 
    // turn on PDO exception handling 
    $con->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION); 
} catch (PDOException $e) { 
    // enter catch block in event of error in preceding try block 
    echo "Connection failed: " . $e->getMessage(); 
} 

try {           
    $sql=("SELECT * FROM books");           
    $results = $con->query($sql);                     
    if ($results->rowcount() == 0) { 
     echo "<p>No books found. </p><br />"; 
    } else {  
     foreach ($results as $row) { 
      $book_id=$row['book_id'];          
      echo "<option value=\"".$book_id."\">".$book_id."</option>"; 
     } 
    } 
} catch (PDOException $e) { 
    echo "Query failed: " . $e->getMessage(); 
} 

mysql_close(); 
?> 

</select> 
<input type="submit" name="submit" value="Remove Book" style="width:auto;"> 
</form> 

這裏是表單提交頁面中的代碼：

<?php        
$host="csdm-mysql"; // Host name 
$username="1001550"; // Mysql username 
$password="1001550"; // Mysql password 
$db_name="db1001550_book_management"; // Database name 

// Connect to server and select database. 
mysql_connect("$host", "$username", "$password")or die("cannot connect"); 
mysql_select_db("$db_name")or die("Cannot select DB"); 

if (isset($_POST['books'])) { 
    $books=$_POST['books']; 
} 

// Remove data from database 
$result=mysql_query("DELETE FROM books WHERE book_id=$books"); 

// if successfully deleted from database, prompt will say book was deleted. 
if ($result) { 
    print "<script type=\"text/javascript\">"; 
    print "alert('Book has been deleted successfully!')"; 
    print "</script>"; 
} else { 
    print "<script type=\"text/javascript\">"; 
    print "alert('Book was not deleted')"; 
    print "</script>"; 
} 

// close connection 
mysql_close(); 
?> 

<form method="post" action="./removeBook.inc.php"> 
           <select name="books"> 
            <option>Please select the Book you wish to delete:</option> 
            <option value='B0001'>B0001</option><option value='B0002'>B0002</option><option value='B0003'>B0003</option><option value='B0004'>B0004</option><option value='B0005'>B0005</option><option value='B0006'>B0006</option><option value='B0007'>B0007</option><option value='B0008'>B0008</option><option value='B0009'>B0009</option><option value='B0010'>B0010</option><option value='B0011'>B0011</option><option value='B0012'>B0012</option><option value='B0013'>B0013</option><option value='B0014'>B0014</option><option value='B0015'>B0015</option><option value='B0016'>B0016</option><option value='B0017'>B0017</option><option value='B0018'>B0018</option><option value='B0019'>B0019</option><option value='B0020'>B0020</option>          
           </select> 
          <input type="submit" name="submit" value="Remove Book" style="width:auto;"> 
          </form> 

感謝您的幫助提前！