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');

edited above to:

if(!defined( 'DB_HOST' )) define( 'DB_HOST', 'localhost' );
if(!defined( 'DB_USER' )) define( 'DB_USER', '68_dev' );
if(!defined( 'DB_PASS' )) define( 'DB_PASS', 'PZ8Jv8p7aqCJwmSy' );
if(!defined( 'DB_NAME' )) define( 'DB_NAME', '68_dev' );

Database.class.php

public function __construct($dbhost = DB_HOST,$dbuser = DB_USER,
                            $dbpass = DB_PASS,$dbname = DB_NAME  ) {
    // set DSN
    $dsn = 'mysql:host=' . $dbhost . ';dbname=' . $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, $dbuser, $dbpass, $options);
    } catch (PDOException $e) {
        $this->error = $e->getMessage();
    }
}

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

private function buildHolder($array) {
for ($i = 0; $i < count($array); $i++) {
    $array[$i] = ':' . $array[$i];
}
return $array;
}

private function buildQuery($table,$field,$holder,$id) {
$query = 'UPDATE ' . $table . ' SET ';
$setStmt[] = NULL; 
for($i = 0;$i < count($field);$i++){
    $setStmt[$i]= $field[$i] . '=' . $holder[$i];
}
$query .= implode(',', $setStmt) .  ' WHERE id=' . $id;
return $query;
}

start custom methods

public function updateQuery($table, $field, $value, $id) {
try {
    if (( gettype($field) != 'array' ) || ( gettype($value) != 'array' )) {
        $field = (array) $field;
        $value = (array) $value;
    }

    $holder = $this->buildHolder($field);
    $array = array_combine($holder, $value);
    if(count($field) > 1){
        $query = $this->buildQuery($table,$field,$holder,$id);
    } else {
        $query = 'UPDATE ' . $table . ' SET ' . implode(',', $field) . '=' .     implode(',', $holder) . 
            ' WHERE id=' . $id;
    }

    $this->query($query);
    $this->bindArray($array);
    $this->execute();
} catch (PDOException $e) {
 $this->error = $e->getMessage();
}
}

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);
}
}

end of custom methods

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/