sub add_item
{
my @item_ref;
my @cart_ref;
my ($dbh, $cart_ref, $item_id, $qty, $color) = @_;
               
	# If the item isn't already in the cart, look it up from the database
	# and store it in the cart as a new entry with a quantity of zero.
	if (!exists ($cart_ref->{$item_id}))
	{
		my $sth = $dbh->prepare ("SELECT item_id, description, category, price, picture, thumbnail, mime_type, color FROM catalog_pet
									WHERE item_id = ?");
		$sth->execute ($item_id);
		my $item_ref = $sth->fetchrow_arrayref ();
		$sth->finish ();
                                 
		return if !defined ($item_ref);	# this shouldn't happen...
		@cart_ref->[0] = {};	# create new entry, indexed by item ID
		@cart_ref->[1] = $item_ref->{description};
                              	@cart_ref->[3] = $item_ref->{price};
		@cart_ref->[8] = 1;
	}
	@cart_ref->[8] = $qty;	
                @cart_ref->[7] = $color;	
                push (@cart_ref, @item_ref);
}