@Override
  public void persistLogicalRequest(LogicalRequest logicalRequest, long topologyRequestId) {
    TopologyRequestEntity topologyRequestEntity = topologyRequestDAO.findById(topologyRequestId);
    TopologyLogicalRequestEntity entity = toEntity(logicalRequest, topologyRequestEntity);
    topologyRequestEntity.setTopologyLogicalRequestEntity(entity);
    //todo: how to handle missing topology request entity?

    //logicalRequestDAO.create(entity);

    topologyRequestDAO.merge(topologyRequestEntity);
  }
Implementation which uses Ambari Database DAO and Entity objects for persistence
of topology related information.
ambari-server/src/main/java/org/apache/ambari/server/topology/PersistedStateImpl.java