doctrine custom oracle driver implementation that will return native types when executing a raw sql statement

Driver.php

<?php

namespace COMPANY\Core\Vendor\Doctrine\DBAL\Driver\OCI8;

use Doctrine\DBAL\Driver\OCI8\Driver as OCIDriver;

class Driver extends OCIDriver
{

  public function connect(array $params, $username = null, $password = null, array $driverOptions = array())
  {
    return new OCI8Connection(
      $username,
      $password,
      $this->_constructDsn($params),
      isset($params['charset']) ? $params['charset'] : null,
      isset($params['sessionMode']) ? $params['sessionMode'] : OCI_DEFAULT,
      isset($params['persistent']) ? $params['persistent'] : false
    );
  }
}

index.php

<?php

// ...

$connectionOptions = array(
  'driverClass' => 'COMPANY\Core\Vendor\Doctrine\DBAL\Driver\OCI8\Driver',
  'user'     => 'user',
  'password' => 'pass',
  'host'     => 'host',
  'port'     => 'port',
  'dbname'     => 'sid',
  'charset'  => 'charset'
);

$em = EntityManager::create($connectionOptions, $config);

// ...

$stmt = $em->getConnection()->prepare("select * from customer");
$stmt->execute();
$result = $stmt->fetchAll();
var_dump($result);

// result
//  [0] =>
//  array(4) {
//    'ID' =>
//    int(1)
//    'FIRSTNAME' =>
//    string(6) "Samuel"
//    'LASTNAME' =>
//    string(4) "Ross"
//    'BIRTHDATE' =>
//    class COMPANY\Core\Util\DateTime\ISO8601DateTime#27 (3) {
//      public $date =>
//      string(26) "1980-09-28 00:00:00.000000"
//      public $timezone_type =>
//      int(3)
//      public $timezone =>
//      string(16) "Europe/Ljubljana"
//    }
//  }

OCI8Connection.php

<?php

namespace COMPANY\Core\Vendor\Doctrine\DBAL\Driver\OCI8;

use Doctrine\DBAL\Driver\OCI8\OCI8Connection as Connection;

class OCI8Connection extends Connection
{
  public function prepare($prepareString)
  {
    return new OCI8Statement($this->dbh, $prepareString, $this);
  }
}

OCI8Statement.php

<?php

namespace COMPANY\Core\Vendor\Doctrine\DBAL\Driver\OCI8;

use COMPANY\Core\Util\DateTime\ISO8601DateTime;
use Doctrine\DBAL\Driver\OCI8\OCI8Statement as Statement;

class OCI8Statement extends Statement
{
  public function fetch($fetchMode = null)
  {
    return $this->_fetchByType(null, $fetchMode);
  }

  public function fetchAll($fetchMode = null)
  {
    return $this->_fetchAllByType(null, $fetchMode = null);
  }

  private function _fetchByType($types = null, $fetchMode = null)
  {
    if ($types == null)
      $types = $this->_getTypeMapping();

    // get row
    $row = parent::fetch($fetchMode);

    // end of iteration
    if (!is_array($row)) {
      return $row;
    }

    foreach ($row as $type => &$v)
    {
      switch ($types[$type])
      {
        case 'NUMBER':
          //NOTE: we explicitly check if a returned number has a dot "." and parse this as float
          //TODO: make regex non-greedy
          //NOTE: find a better way to do this, since its an expensive operation
          $r = preg_match('/\./', $v);

          if ($r == false || $r == 0) {
            $v = intval($v);
          } else {
            $v = floatval($v);
          }
          break;
        //string
        case 'CHAR':
        case 'NCHAR':
        case 'VARCHAR':
        case 'NVARCHAR':
        case 'NVARCHAR2':
        case 'CLOB':
        case 'NCLOB':
          if ($v != null) {
            $v = strval($v);
          }
          break;
        case 'VARCHAR2':
          if ($v != null)
          {
            //NOTE: we support the UTC ISO8601 format -> 2014-07-02T05:03:54Z
            //NOTE: find a better way to do this, since its an expensive operation
            $r = preg_match('/(\d{4})-(\d{2})-(\d{2})T(\d{2}):(\d{2}):(\d{2})Z/', $v);
            if($r == 0 || $r == false) {
              // string
              $v = strval($v);
            } else {
              $v = ISO8601DateTime::createFromFormat('Y-m-d\TH:i:s\Z', $v);
            }
          }
          break;
        case 'DATE':
          if ($v != null) {
            //NOTE: we support the ISO8601 date format (YYYY-MM-DD -> 2014-07-02)
            //TODO: require to_date from oracle, consolidate the "d-M-y" format!
            $v = ISO8601DateTime::createFromFormat('d-M-y', $v);
            $v->setTime(0, 0, 0);
          }
          break;
        default:
          throw new \Exception("Oracle type \"".$types[$type]."\" not supported.");
          break;
      }
    }

    return $row;
  }

  private function _fetchAllByType($types = null, $fetchMode = null)
  {
    if ($types == null)
      $types = $this->_getTypeMapping();

    $result = array();
    while($row = $this->_fetchByType($types, $fetchMode))
      $result[] = $row;

    return $result;
  }

  private function _getTypeMapping()
  {
    oci_execute($this->_sth, OCI_DESCRIBE_ONLY);
    $cols = oci_num_fields($this->_sth);

    $types = array();
    for ($i = 1; $i <= $cols; ++$i) {
      $column = oci_field_name($this->_sth, $i);
      $type = oci_field_type($this->_sth, $i);

      $types[$column] = $type;
    }

    if (count($types) === 0)
      return null;

    return $types;
  }
}