public function getColumn($name, $use_alias = false)
    {
        if ($use_alias) {
            foreach ($this->columns as $column) {
                if (0 === strcasecmp($name, $column->getName($use_alias))) {
                    return $column;
                }
            }
        } else {
            $key = strtolower($name);
            if (isset($this->columns[$key])) {
                return $this->columns[$key];
            }
        }

        return null;
    }