public List<String> getRespDataTypeList() {
    if (respDataTypeList == null) {
      respDataTypeList = new ArrayList<>();
      for (ColumnHeader columnHeader : columnHeaders) {
        respDataTypeList.add(columnHeader.getColumnType().toString());
      }
    }
    return respDataTypeList;
  }
The header of query result dataset.
iotdb-core/datanode/src/main/java/org/apache/iotdb/db/queryengine/common/header/DatasetHeader.java