incrementing a field in an SQL table by 1, using forms and PHP

[georgehowell]

Hi there

the following table that is populated dynamically from SQL table.

<?php

try{

      $database = "SkyZone";

    $username = "root";

    $password = "";

 

    // connect to database

$db = new PDO("mysql:host=localhost;dbname=$database",$username,$password);

$query = "SELECT id, title, on_hand FROM SZ_products order by on_hand asc;";

$table =$db->query($query);

echo "<form method='post' name='onHandID' action='updateInventory.php'>";

echo "<table width='550px' class='altrowstable' id='alternatecolor'>";

foreach($table as $row)

{

        echo "<tr id='row'>\n";

echo "<td style='text-align:center'>" . $row['id'] . "</td>";

echo "<td style='padding-left:5px'>" . $row['title'] . "</td>";

echo "<td style='text-align:right'>" . $row['on_hand'] . "</td>";

        echo "<td><input name='onHandID' type='submit' value='add'></td>";

echo "</tr>";

}

echo "</table></form>";

//destroy the PDO object

$db = null;

//if connection fails throw a PDO exception

}catch (PDOException $e) {

    print "Error!: " . $e->getMessage() . "<br/>";

    die();

}

?>

 

The "add" button is intended to increment the value "on_hand" by one. Here's the PHP files called on submit:

 

"updatedInventory.php"

 

<?php

ob_start();

require_once("lib/class_loader.php");

session_start();

ob_flush();

 

$user = $_SESSION['user'];

$user->updateInventory($_GET);

 

include("Admin_4.php");

?>

 

"Administrator.php"

 

<?php

class Administrator extends User

{

    public function __construct()  {

      parent::__construct();

    }

public function updateInventory($on_hand) {

  $ps = $this->db->prepare("UPDATE SZ_products SET on_hand= on_hand+1 WHERE onHandID = $on_hand");

  $ps->execute(array($on_hand));

  return ($ps->rowCount() == 1);

}

}

 

The "WHERE" /sql part of the query is not working here.

 

Any comments appreciated

cheers, George