PHP PDO Custom class ple

i created a database class from a good tutorial and wanted to put it up here so it would get in some search results. it took me about 2 days to find it. also i added a few custom functions to it.. here it is :P and if there is something that can be done better or more proficiently please feel free to let me know.

config.php:

// Database Constants
defined('DB_HOST') ? NULL : define('DB_HOST', 'edit:host');
defined('DB_USER') ? NULL : define('DB_USER', 'edit:user');
defined('DB_PASS') ? NULL : define('DB_PASS', 'edit:pass');
defined('DB_NAME') ? NULL : define('DB_NAME', 'edit:databasename');

database.class.php:

class Database {

private $dbhost = DB_HOST;
private $dbuser = DB_USER;
private $dbpass = DB_PASS;
private $dbname = DB_NAME;
private $dbh;
private $error;
private $stmt;

public function __construct() {
    // set DSN
    $dsn = 'mysql:host=' . $this->dbhost . ';dbname=' . $this->dbname;
    // set OPTIONS
    $options = array(
        PDO::ATTR_PERSISTENT => TRUE,
        PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION
    );
    // Create a new PDO instance
    try {
        $this->dbh = new PDO($dsn, $this->dbuser, $this->dbpass, $options);
    } catch (PDOException $e) {
        $this->error = $e->getMessage();
    }
}

public function query($query) {
    $this->stmt = $this->dbh->prepare($query);
}

public function selectQuery($table, $fields, $FieldToQuery, $value) {
    try {
        if ((gettype($fields) != 'array') || (gettype($value) != 'array')) {
            $fields = (array) $fields;
            $FieldToQuery = (array) $FieldToQuery;
            $value = (array) $value;
        }
        $holders = $FieldToQuery;
        for ($i = 0; $i < count($holders); $i++) {
            $holders[$i] = ':' . $holders[$i];
        }
        $array = array_combine($holders, $value);
        $query = 'SELECT ' . implode(',', $fields) . ' FROM ' . $table . ' WHERE ' .
         implode(',',$FieldToQuery) . ' = ' . implode(',', $holders);
        $this->query($query);
        $this->bindArray($array);
        $rows = $this->resultset();
        return $rows;
    } catch (PDOException $e) {
        $this->error = $e->getMessage();
    }
}

public function insertQuery($table, $fields, $values) {
    try {
        if ((gettype($fields) != 'array') || (gettype($values) != 'array')) {
            $fields = (array) $fields;
            $values = (array) $values;
        }
        $holders = $fields;
        for ($i = 0; $i < count($holders); $i++) {
            $holders[$i] = ':' . $holders[$i];
        }
        $array = array_combine($holders, $values);
        $query = 'INSERT INTO ' . $table . '(' . implode(',', $fields)
                . ') VALUES (' . implode(',', $holders) . ')';
        $this->query($query);
        $this->bindArray($array);
        $this->execute();
    } catch (PDOException $e) {
        $this->error = $e->getMessage();
    }
}

public function bindArray($array) {
    foreach ($array as $key => $value) {
        $this->bind($key, $value);
    }
}

public function bind($param, $value, $type = null) {
    if (is_null($type)) {
        switch (true) {
            case is_int($value):
                $type = PDO::PARAM_INT;
                break;
            case is_bool($value):
                $type = PDO::PARAM_BOOL;
                break;
            case is_null($value):
                $type = PDO::PARAM_STR;
        }
    }
    $this->stmt->bindValue($param, $value, $type);
}

public function execute() {
    $this->stmt->execute();
}

public function resultset() {
    $this->execute();
    return $this->stmt->fetchAll(PDO::FETCH_ASSOC);
}

public function single() {
    $this->execute();
    return $this->stmt->fetchAll(PDO::FETCH_ASSOC);
}

public function rowCount() {
    return $this->stmt->rowCount();
}

public function lastInsertId() {
    return $this->dbh->lastInsertId();
}

public function beginTransaction() {
    return $this->dbh->beginTransaction();
}

public function endTransaction() {
    return $this->dbh->commit();
}

public function cancelTransaction() {
    return $this->dbh->rollBack();
}

public function debugDumpParams() {
    return $this->stmt->debugDumpParams();
}

}

here is the link http://culttt.com/2012/10/01/roll-your-own-pdo-php-class/