anchor.diff:    PRIMARY KEY (`name`),
     UNIQUE KEY `name` (`name`),
     KEY `fk_study_users` (`username`)
  --- , CONSTRAINT `fk_study_users` FOREIGN KEY (`username`) REFERENCES `users` (`email`) ON DELETE CASCADE
   ) ENGINE=NDBCLUSTER DEFAULT CHARSET=latin1;
   /*!40101 SET character_set_client = @saved_cs_client */;
   
  
positive.code:   `added_by` varchar(255) NOT NULL,
    `team_role` enum('Master','Researcher','Guest') NOT NULL,
    PRIMARY KEY (`studyname`,`username`)
  -- ,  CONSTRAINT `FK_study_group_members_studyname` FOREIGN KEY (`studyname`) REFERENCES `study` (`name`)
  ) ENGINE=NDBCLUSTER DEFAULT CHARSET=latin1;
  /*!40101 SET character_set_client = @saved_cs_client */;
  
  
negative.code:   UNIQUE KEY `uid_UNIQUE` (`uid`),
    UNIQUE KEY `serial_UNIQUE` (`serial`),
    UNIQUE KEY `public_id_UNIQUE` (`public_id`)
  ) ENGINE=NDBCLUSTER  DEFAULT CHARSET=latin1;
  /*!40101 SET character_set_client = @saved_cs_client */;
  
  