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