@Transactional
  public AlertGroupEntity merge(AlertGroupEntity alertGroup) {
    return entityManagerProvider.get().merge(alertGroup);
  }
Merge the speicified alert group with the existing group in the database.

@param alertGroup
         the group to merge (not {@code null}).
@return the updated group with merged content (never {@code null}).
ambari-server/src/main/java/org/apache/ambari/server/orm/dao/AlertDispatchDAO.java