Ejemplo de funciones delphi para convertir Json a registro de un DataSet y viceversa.

function DataRowToJSONObject(const AValue : TDataSet): TJSONObject;
var
  I: Integer;
  AString : String;
begin
  Result := TJSONObject.Create();
  for I := 0 to AValue.FieldDefs.Count-1 do
  begin
    case AValue.FieldDefs[I].DataType of
      ftString, ftWideString, ftMemo :
        begin
          if AValue.FieldByName(AValue.FieldDefs[I].Name).AsString <> '' then
            Result.AddPair(AValue.FieldDefs[I].Name, AValue.FieldByName(AValue.FieldDefs[I].Name).AsString)
          else
            Result.AddPair(AValue.FieldDefs[I].Name, ' ');
        end;
      ftSmallint, ftInteger, ftWord, ftLongWord, ftShortint :
        begin
          Result.AddPair(AValue.FieldDefs[I].Name, TJSONNumber.Create(AValue.FieldByName(AValue.FieldDefs[I].Name).AsInteger));
        end;
      ftFloat, ftCurrency :
        begin
          Result.AddPair(AValue.FieldDefs[I].Name, TJSONNumber.Create(AValue.FieldByName(AValue.FieldDefs[I].Name).AsFloat));
        end;
      ftBoolean :
        begin
          Result.AddPair(AValue.FieldDefs[I].Name, AValue.FieldByName(AValue.FieldDefs[I].Name).AsString)
        end;
    end;
  end;
end;
 
function JSONObjectToDataRow(const AJson : TJSONObject; const AValue : TDataSet): Boolean;
var
  I: Integer;
begin
  Result := False;
  for I := 0 to AValue.FieldDefs.Count - 1 do
  begin
    case AValue.FieldDefs[I].DataType of
      ftString, ftWideString, ftMemo :
        begin
          AValue.FieldByName(AValue.FieldDefs[I].Name).AsString :=
            AJson.Get(AValue.FieldDefs[I].Name).JsonValue.Value;
        end;
      ftSmallint, ftInteger, ftWord, ftLongWord, ftShortint :
        begin
          AValue.FieldByName(AValue.FieldDefs[I].Name).AsInteger :=
            (AJson.Get(AValue.FieldDefs[I].Name).JsonValue as TJsonNumber).AsInt;
        end;
      ftFloat, ftCurrency :
        begin
          AValue.FieldByName(AValue.FieldDefs[I].Name).AsFloat :=
            (AJson.Get(AValue.FieldDefs[I].Name).JsonValue as TJsonNumber).AsDouble;
        end;
      ftBoolean :
        begin
          AValue.FieldByName(AValue.FieldDefs[I].Name).AsBoolean :=
            StrToBool(AJson.Get(AValue.FieldDefs[I].Name).JsonValue.Value);
        end;
    end;
  end;
end;