Converting MySQL connector to PDO - php

Question

After taking some advice from people on here in a previous thread, I'm trying to convert my MySQL to PDO, but am running into some issues.
Here is my original MySQL connection class:
class DbConnector {
public static function getInstance() {
static $instance = null;
if ($instance === null) {
$instance = new DbConnector();
}
return $instance;
}
protected $theQuery;
private $link;
function DbConnector() {
$host = 'localhost';
$db = '';
$user = '';
$pass = '';
// connect to the db
$this->link = mysql_connect($host, $user, $pass);
mysql_select_db($db);
register_shutdown_function(array(&$this, 'close'));
}
public function find($query) {
$ret = mysql_query($query, $this->link);
if (mysql_num_rows($ret) == 0)
return array();
$retArray = array();
while ($row = mysql_fetch_array($ret))
$retArray[] = $row;
return $retArray;
}
public function insert($query) {
$ret = mysql_query($query, $this->link);
if (mysql_affected_rows() < 1)
return false;
return true;
}
public function query($query) {
$this->theQuery = $query;
return mysql_query($query, $this->link);
}
public function fetchArray($result) {
return mysql_fetch_array($result);
}
public function close() {
mysql_close($this->link);
}
public function exists($query) {
$ret = mysql_query($query, $this->link);
if (mysql_num_rows($ret) == 0)
return false;
}
public function last_id($query) {
return mysql_insert_id($query);
}
}
Here is the function that I'm writing:
function getRandomSubmission() {
global $db;
if(!empty($_GET['id'])){
$submission_id = $_GET['id'];
$query = $db->find("
SELECT
*
FROM
`submissions`
WHERE id = '{$submission_id}'
LIMIT 1
");
}
else {
$query = $db->find("
SELECT
*
FROM
`submissions`
ORDER BY RAND()
LIMIT 1
");
}
if($query) {
return $query[0];
}
else {
$query = $db->find("
SELECT
*
FROM
`submissions`
ORDER BY RAND()
LIMIT 1
");
}
}
Here is the PDO connector:
$host = 'localhost';
$username = '';
$pass = '';
$db = '';
try {
$dbh = new PDO("mysql:host=$host;dbname=$db", $username, $pass);
} catch (PDOException $e) {
echo $e->getMessage();
}
Here is what I've tried to convert it to, but it's just plain wrong. I think I need to be returning a PDO associative array in the 2nd if statement, but am not sure.
function getRandomSubmission() {
global $dbh;
if(!empty($_GET['id'])){
$submission_id = $_GET['id'];
$stmt = $dbh->prepare('
SELECT
*
FROM
`submissions`
WHERE
`id` = ?
LIMIT 1
');
$stmt->bindParam(1, $submission_id, PDO::PARAM_INT);
$stmt->execute();
}
else {
$stmt = $dbh->prepare('
SELECT
*
FROM
`submissions`
ORDER BY RAND()
LIMIT 1
');
$stmt->execute();
}
if($stmt) {
return $stmt[0];
}
else {
$stmt = $dbh->prepare('
SELECT
*
FROM
`submissions`
ORDER BY RAND()
LIMIT 1
');
$stmt->execute();
}
}
The original one works as intended, however (I realize I left the connection details blank).

Answer 1

You need to call fetch method of the PDOStatement object:
return $stmt->fetch()
Read about the fetch style, really you don't need FETCH_BOTH ;-)