@Override
  public void setFetchDirection(int direction) throws SQLException {
    checkConnection("setFetchDirection");
    if (direction != ResultSet.FETCH_FORWARD) {
      throw new SQLException(String.format("direction %d is not supported!", direction));
    }
  }
There are two kinds of sql here: (1) query sql (2) update sql.

<p>(1) return IoTDBJDBCResultSet or IoTDBNonAlignJDBCResultSet (2) simply get executed
iotdb-client/jdbc/src/main/java/org/apache/iotdb/jdbc/IoTDBStatement.java