public static function run($query, $params=array()) {
		
		$self = static::getInstance();
		
		$self->openConnection();
		
		$ret = NULL;
		
		try {
			
			// prepare query
			$stat = $self->handler->prepare($query);

			// bind parameters
			$stat->execute((array)$params);

			// count affected rows
			$affected = $stat->rowCount();
			
		} catch (\PDOException $e) {
			
			// logger
			$self->logParamQuery($query, 0, $params);
			
			switch ($e->getCode()) {
				
				// integrity constraint violation
				/*
				 case '23000':
					 $message = 'Database integrity constraint violation';
					 break;
				 */
				default:
					$message = $e->getMessage();
					break;
			}
			
			$self->addError($message);
			
			$affected = 0;
			
		} catch (\Exception $e) {
			
			// logger
			$self->logParamQuery($query, 0, $params);
			$self->addError($e->getMessage());
			$affected = 0;
			
		}
		
		$stat->closeCursor();
		$self->logParamQuery($query, $affected, $params);
		
		return $affected;
			
	}