protected function GetColumns()
	{
		if (!$this->ModelName)
		{
			throw new Exception("ModelName must be defined in " . get_class($this) . "::GetColumns");
		}

		$counter = 0;
		$props = array();
		foreach (get_class_vars($this->ModelName)as $var => $val)
		{
			$props[$counter++] = $var;
		}
		return $props;
	}