Undefined class constant 'DBLIB_ENCODING_BINARY'

I've tried to install Drupal 7 + dblib in Ubuntu 12.04 + Apache 2.4.7 + PHP 5.5.9. Installation was fine but when I try to access index.php, it didn't show anything and an error shows at /var/log/apache2/error.log

PHP Fatal error:  Undefined class constant 'DBLIB_ENCODING_BINARY' in /var/www/html/drupal/includes/database/dblib/query.inc on line 95

Here's the source code for query.inc on line 95

$stmt->bindParam($placeholder, $data_values[$placeholder . $insert_index], PDO::PARAM_LOB, 0, PDO::DBLIB_ENCODING_BINARY);

Any idea how to solve "Undefined class constant 'DBLIB_ENCODING_BINARY'"?