Spring Joining table insert. Skip adding records to other table in join. Persist data only to main and link table - spring-boot

Question

Help me in Entity design with the for following E-R.
Here I need to insert entries into REQUEST table and REQ_TYPE_MAP table. There shouldn't be any entry to TYPE_MAST table.
TYPE_MAST contains master data that are loaded once. I need to map the master data to a request.
But the below approach that I use had adding entries to TYPE_MAST table too. How can I avoid that.
Request Entity
#Entity
#Table(name="REQUEST")
public class Request implements Serializable {
private static final long serialVersionUID = 1L;
#Id
#Column(name="REQUEST_ID")
private long requestId;
#Column(name="CIVILID")
private Long civilId;
#Column(name="MOBILE_NO")
private Long mobileNo;
#ManyToMany(cascade ={ CascadeType.PERSIST, CascadeType.MERGE})
#JoinTable(name="REQ_TYPE_MAP",
joinColumns = #JoinColumn(name="REQUEST_ID"),
inverseJoinColumns = #JoinColumn(name="TYPE_ID")
)
private Set<MsaDisabScreenRequest> disabilities= new HashSet<MsaDisabScreenRequest>()
/**
getters & setters
equals() & hashCode()
**/
}
Type Mast Entity
#Entity
#Table(name="TYPE_MAST")
public class MsaDisabMaster implements Serializable {
private static final long serialVersionUID = 1L;
#Id
#Column(name="TYPE_ID")
private long disTypeId;
#Column(name="NAME")
private String name;
/**
getters & setters
equals() & hashCode()
**/
}
Request DTO
public class RequestDto implements Serializable {
private static final long serialVersionUID = 1L;
private long requestId;
private Long civilId;
private Long mobileNo;
private Set<MsaDisabScreenRequestDto> disabilities= new HashSet<MsaDisabScreenRequestDto>()
/**
getters & setters
equals() & hashCode()
**/
}
Type Mast Dto
public class MsaDisabMasterDto implements Serializable {
private static final long serialVersionUID = 1L;
private long disTypeId;
private String name;
/**
getters & setters
equals() & hashCode()
**/
}
Using spring JPA to persist.
#Service code relevant to save(let me know if you required more details).
Service
#SuppressWarnings("all")
public class ReqServiceImpl implements ReqService {
#Autowired
MsaRepository msaRepository;
#Autowired
private OrikaBeanMapper mapper;
#Override
#Transactional(rollbackOn = BusinessException.class)
public long saveScreeningRequest(RequestDto requestDto) throws BusinessException {
try {
// mapping
Request request = mapper.map(requestDto,Request.class);
Request res = reqRepository.save(request);
if (msaDisabScreenRes != null) {
return res.getRequestId();
} else {
//throw exception
}
} catch (DataAccessException e) {
//throw exception
}
}
}

Answer 1

First of all, since MsaDisabMaster is a permanent data, I recommend to make it immutable.
As MsaDisabMaster objects are already persisted then you must remove cascading from its reference in Request.
In your service you should 'attach' all MsaDisabMaster that are contained in RequestDto to the resulted Request. You can do this with getOne method of your MsaDisabMaster repository, something like this:
requestDto.getDisabilities()
.forEach(m -> request.getDisabilities().add(msaDisabMasterRepo.getOne(m.getDisTypeId())));
Then you can save request using save() method of the Request repository.

Answer 2

Please check this example:
https://www.mkyong.com/hibernate/hibernate-many-to-many-relationship-example-annotation/
This should work for you
#ManyToMany(fetch = FetchType.PERSIST, cascade = CascadeType.MERGE)
#JoinTable(name = "REQ_TYPE_MAP",joinColumns = {
#JoinColumn(name = "REQUEST_ID", nullable = false, updatable = false) },
inverseJoinColumns = { #JoinColumn(name = "TYPE_ID",
nullable = false, updatable = false) })