anchor.diff:              Query::string(),
               Interpolations::[{binary(), binary()}],
               Cover::term()) ->
  -            {ColumnNames::[binary()], Rows::[tuple()]} | {error, term()}.
  +            {ok, {ColumnNames::[binary()], Rows::[tuple()]}} | {error, term()}.
   %% @equiv query/5.
   query(Pid, Query, Interpolations, Cover) ->
       query(Pid, Query, Interpolations, Cover, []).
  
positive.code: 
  
  -spec query(pid(), Query::string()|binary()) ->
                     {ColumnNames::[ts_columnname()], Rows::[tuple()]} | {error, Reason::term()}.
  %% @equiv query/5.
  query(Pid, Query) ->
      query(Pid, Query, [], undefined, []).
  
  -spec query(pid(), Query::string()|binary(), Interpolations::[{binary(), binary()}]) ->
                     {ColumnNames::[binary()], Rows::[tuple()]} | {error, term()}.
  %% @equiv query/5.
  query(Pid, Query, Interpolations) ->
      query(Pid, Query, Interpolations, undefined, []).
  
negative.code:             Interpolations::[{binary(), binary()}],
              Cover::term(),
              Options::proplists:proplist()) ->
              {ok, {ColumnNames::[binary()], Rows::[tuple()]}} | {error, term()}.
  %% @doc Execute a Query with client.  The result returned
  %%      is a tuple containing a list of columns as binaries in the
  %%      first element, and a list of records, each represented as a
  