In PostgreSQL there are a function table_to_xml to map the table content to xml value but there are no functionality to decompose xml back into table which can be used in system that uses xml for transport only or there are a need to migrate to database system to use database functionality. I propose to have this by extending copy to handle xml format as well because file parsing and tuple formation functions is in there and it also seems to me that implement it without using xml library is simpler
