Quanity update

PHP
1

please i am trying to make an update in a database where changes have been made to quantity,but i need a guide where the change is update is only made to where the change is done.

this is the code where the changes would be done




    <?
    $pplresult = mysql_query("SELECT * FROM repplac");
    echo "<table border='1'><tr><th> SHOP NAME</th><th> PRODUCT NAME</th><th>
    PRODUCT SIZE</th><th> PRODUCT COLOUR</th><th> PRODUCT QUANTITY</th><th>
    PRICE</th><th> </th></tr>";
    while($row = mysql_fetch_assoc($pplresult)){?>
    <form action='updatepplac.php' method='Post' class='slistbar'>
    <?echo "<tr><td>" .$row['Sname'] ."</td><td>" .$row['Pname'] ."</td><td>" .$row['Psize'] ."</td><td>" .$row['Pcolour'] ."</td><td>" ."<input type='text' name='Pquantity' id='Pquantity' value='{$row['Pquantity']}' >" ."</td><td>" .$row['Price'] ."</td><td>" ?>
    <a href="deleteproduct.php?del=<?php echo $row['Pidno'];?>">delete</a></td></tr><?php }
    // table closing tag
    ?>

and the update script




    $submit = $_POST['submit'];
            $pid = $_GET['del'];
            $nPquantity = $_POST['Pquantity'];
            //echo "$nPquantity";

            //die();
            if('POST' === $_SERVER['REQUEST_METHOD'])
            {
            $queryreg = mysql_query("
            UPDATE repplac SET Pquantity='$nPquantity' ")or die(mysql_error());
            }

i KNOW I HAVE NOT SPECIFIED WHERE THE UPDATE IS TO BE DONE, WHEN I ECHOED THE QUANTITY CHANGE, IT ONLY CAME BACK, WITH RESULT WHERE THE LAST ROW WAS CHANGED AND NOT ALL WHERE CHANGES WHERE DONE, AND I DID NOT KNOW THE FUNCTION TO BRING THE POST VARIABLE BCK IN ARRAY TO CHECK THE VARIABLE RETURNED, PLEASE I NEED A GUIDE THANKS ON HOW TO MAKE UPDATE CHANGES AT THE RIGHT PLACES.THANKS

2

shouldn’t there be a WHERE in that UPDATE query somewhere?

mysql_query("UPDATE repplac SET Pquantity='$nPquantity' WHERE your_id_column = '$pid'")or die(mysql_error());