anchor.diff:      insert(atom_to_list(Table), Props, Context);
   insert(Table, Props, Context) ->  
       assert_table_name(Table),
  -    Cols = columns(Table, Context),
  +    Cols = column_names(Table, Context),
       InsertProps = prepare_cols(Cols, Props),
       C = get_connection(Context),
   
  
positive.code:     end.
  
  split_props(Props, Cols) ->
      {CProps, PProps} = lists:partition(fun ({P,_V,_M}) -> proplists:is_defined(P, Cols) end, Props),
      case PProps of
          [] -> ok;
          _  -> z_utils:assert(proplists:is_defined(props, Cols), {unknown_column, PProps})
      end,
      {CProps, PProps}.
  
  
negative.code:     update(atom_to_list(Table), Id, Parameters, Context);
  update(Table, Id, Parameters, Context) ->
      assert_table_name(Table),
      Cols         = column_names(Table, Context),
      UpdateProps  = prepare_cols(Cols, Parameters),
      C            = get_connection(Context),
      UpdateProps1 = case proplists:is_defined(props, UpdateProps) of
  