Saves rating (1-5) of 'id' in MySQL database input: id, stars output: html success or fail, new total votes

rateview.php

<?php
header("Cache-Control: no-cache");
header("Pragma: nocache");
include("../phpsqlajax_dbinfo.php");
$units=5.0; // number of units possible
$id_sent = $_GET['id'];
$vote_sent = $_GET['stars'];
$ip =$_SERVER['REMOTE_ADDR'] ;

try {
$dbConnection = new PDO("mysql:dbname=$database;host=$host;charset=utf8", $username, $password);
$dbConnection->setAttribute(PDO::ATTR_EMULATE_PREPARES, false);
$dbConnection->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
    // Yay!
    }
catch(PDOException $e)
    {
    echo $e->getMessage();
    }

// statement
$insert_id_date = $dbConnection->prepare("
  	INSERT INTO ratings_view (id, date)
		VALUES (:id_sent, now())
");
$insert_id_date->bindValue(':id_sent', $id_sent);

try {
// Making sure the marker exists to maintain consistency and check if a vote exists
$select_id = $dbConnection->prepare("SELECT
			ratings_view.id as id
FROM		ratings_view
RIGHT JOIN	markers
ON			markers.id = ratings_view.id
WHERE 		ratings_view.id = :id_sent");
$select_id->bindValue(':id_sent', $id_sent);
$select_id->execute();
$result_select_id = $select_id->fetch(PDO::FETCH_ASSOC);
// If there is no vote cast for this markerid yet
if (!$result_select_id) {
	// Start by inserting the markerid and the date
	$insert_id_date->execute();
}

} catch (Exception $e) {
	die("marker does not exist."); //normal users will never see this
} // end of try


if ($vote_sent > $units || $vote_sent < 1.0) die("sorry, vote seems to be invalid."); // kill the script because a wrong vote has been given. Impossible for normal users and makes sure votes are within range

//connecting to the database to get some information
$get_votes_value_ips = $dbConnection->prepare("
	SELECT	total_votes,
			total_value,
			used_ips
	FROM	ratings_view
	WHERE	id = :id_sent");
$get_votes_value_ips->bindValue(':id_sent', $id_sent);
$get_votes_value_ips->execute();
$result_get_votes_value_ips = $get_votes_value_ips->fetch(PDO::FETCH_ASSOC);

$checkIP = unserialize($result_get_votes_value_ips['used_ips']); // unserialize all used ips
$total_votes = $result_get_votes_value_ips['total_votes']; //how many votes total
$current_total_value = $result_get_votes_value_ips['total_value']; //total value of all ratings added together and stored
$new_total_value = $vote_sent + $current_total_value; //add together the current total value and the newest vote
//$tense = ($total_votes == 1) ? "vote" : "votes"; //plural form votes/vote --> unused

// checking to see if the first vote has been tallied
// or increment the current number of votes
($new_total_value==0 ? $added=0 : $added=$total_votes+1); // is this is a double check? votes of zero are already ignored?

// ip cookie check when voting
// if a cookie entry of this marker + view is not yet set (i.e. there is not yet voted for this entry)
if(!isset($_COOKIE['rating_view_'.$id_sent])) {
	// then check also if the user's ip address is used before to vote on this marker
	$get_used_ip = $dbConnection->prepare("
		SELECT		used_ips
		FROM		ratings_view
		WHERE		used_ips LIKE '%".$ip."%'
		AND 		id = :id_sent");
	//$get_used_ip->bindValue(':ip', $ip); //if it works, try it with :ip
	$get_used_ip->bindValue(':id_sent', $id_sent);
	$get_used_ip->execute();
	// if there is a reply (= a row), it means the ip has been found
	$hasvoted = ($get_used_ip->fetch());
	//$hasvoted = $result_get_used_ip->rowCount();
} 
else {
	// i.e. there is a cookie entry found for this marker + view --> has voted for sure
	$hasvoted = 1;
}

if (!$hasvoted) {  // if the user has not voted, vote normally
	// prepare ip array
	// if checkIP is an array (i.e. it has already entries) then push in another value
	((is_array($checkIP)) ? array_push($checkIP, $ip) : $checkIP=array($ip));
	$insertip = serialize($checkIP); 
	
	try {
		$update_rating = $dbConnection->prepare("
			UPDATE 	ratings_view
			SET		total_votes = :added,
					total_value = :new_total_value,
					used_ips = :insertip
			WHERE	id = :id_sent");
		$update_rating->bindValue(':added', $added);
		$update_rating->bindValue(':new_total_value', $new_total_value);
		$update_rating->bindValue(':insertip', $insertip);
		$update_rating->bindValue(':id_sent', $id_sent);
		$update_rating->execute();
		// check if the row has been affected
		$result_update_rating = $update_rating->rowCount();
		// if UPDATE query is succesful (1 row = affected) set cookie (30 day validity)
		if ($result_update_rating) setcookie("rating_view_" . $id_sent , 1 , time() + 3600*24*30); 
	} catch (Exception $e) {
		throw $e;
	}
} //end of if(!hasvoted)


// todo: return array with number of votes

// if saving the rating was succesful, the script will get here, otherwise will die earlier. So no need to check again for rowCount()
// if the user hadn't voted before
if (!$hasvoted) { 
	$return_value_html = '&nbsp;<img src="images/green_check.png" width="16 height="16">';
	$return_total_votes_html = $added; // return also the new total amount of votes
} else { // the user had already voted (ip exists / cookie exists)
	$return_value_html = '<span class="invalid" style="font-size:0.7em;">&nbsp;<img src="images/red_cross.png" width="16" height="16"><br>Already voted for this item</span>';
	$return_total_votes_html = $total_votes; // total votes stay the same as it was before the vote
}

$return_html = array('outcome' => $return_value_html, 'total_votes' => $return_total_votes_html);
echo json_encode($return_html); // return as json array (use dataType "json" in ajax to read corectly)

?>