public function getColumnSettings($columns = null)
	{
		if(null == $columns)
		{
			$columns = array_map(function($descriptor)
				{
					return zend_column_name($descriptor);
				},
				$this->getColumns()
			);
		}

		$k = array_find_key($columns, function($v, $k){
				return $v == $this->getPrimaryKey();
			}
		);

		if(null !== $k)
		{
			unset($columns[$k]);
		}

		return  array_join($columns, $this->_settings, false);

	}