anchor.diff:  %%      If such a tuple does not exists nothing is changed.
   -spec delete(DBName::db(), Key::key()) -> db().
   delete(DBName, Key) ->
  -    mnesia:transaction(fun()-> mnesia:delete({DBName, Key}) end),
  +    {atomic, _} = mnesia:transaction(fun()-> mnesia:delete({DBName, Key}) end),
       DBName.
   
   %% @doc Returns the name of the DB specified in new/1.
  
positive.code:           io:format("starting mnesia: ~w~n", [Msg]),
            io:format("starting mnesia: maybe you tried to start a new node "
                      "while we still found persisted data of a node with the "
                     "same name. If you want to get rid of the old persisted "
                      "data, delete them using ~p.~n",
                      ["rm -rf data/" ++ atom_to_list(node())]),
            erlang:halt()
  
negative.code: -spec close(DBName::db()) -> true.
  close(DBName) ->
    ?TRACE("close:~nDB_name:~p~n",[DBName]),
    {'atomic',_} = mnesia:transaction(fun()-> mnesia:delete_table(DBName)end),
    true.
  
  %% @doc Closes and deletes the DB named DBName
  -spec close_and_delete(DBName::db()) -> true.
  close_and_delete(DBName) ->
    ?TRACE("close:~nDB_name:~p~n",[DBName]),
    {'atomic',_} = mnesia:transaction(fun()-> mnesia:delete_table(DBName)end),
    true.
  
  %% @doc Saves arbitrary tuple Entry or list of tuples Entries
  %%      in DB DBName and returns the new DB.
  