PHP update is not updating database with checkbox

PHP update is not updating database with checkbox

to all i have a weird problem when i am trying to update a table of my
database with checkboxes it takes only one value and all the rest just
ingnores them here is my php code so far
foreach ($_POST['choice'] as $id){
$price=$_POST['price'][$id];
$availability=$_POST['availability'][$id];
$result1=mysql_query("UPDATE store SET
storeid='".$id."',availability='".$availability."', price='".$price."'
WHERE productid='".$par1."'");
}