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: -spec close(DBName::db()) -> true.
  close(DBName) ->
    ?TRACE("close:~nDB_name:~p~n",[DBName]),
    mnesia:transaction(fun()-> mnesia:delete_table(DBName)end).
  
  %% @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]),
    mnesia:transaction(fun()-> mnesia:delete_table(DBName)end).
  
  %% @doc Saves arbitrary tuple Entry or list of tuples Entries
  %%      in DB DBName and returns the new DB.
  
negative.code:       case mnesia:create_schema([node()]) of
          ok ->
            io:format("starting mnesia: no previous Schema to recover from.~n"),
            ok = mnesia:delete_schema([node()]),
            erlang:halt();
          {error, {_, {already_exists, _}}} ->
            io:format("starting mnesia: recovering.~n");
  