ManyToOne « Map « JPA Q&A

1. Two entities with @ManyToOne should join the same table

I have the following entities Student

public class Student implements Serializable {

  @GeneratedValue(strategy = GenerationType.AUTO)
  private Long id;

  //getter and setter for id

public class Teacher implements Serializable {


2. Hibernate @ManyToOne on inconsistent database

Let's say I have two tables, employee and department where emp has a @ManyToOne key to dept. Now I want to be able to delete rows from the dept table but ...

3. What is the difference between @ManyToOne(optional=false) vs. @Column(nullable=false)

In JPA, I am confused when to use the attribute optional=false and the annotation @column(nullable=false). What is the difference?

4. Hibernate.Envers: @Audited at @ManyToOne throws Exception

there are following two classes, related by manytoone-annotation:

public class Firma {
  private int id;

  @OneToMany(mappedBy = "firma")
  private List<Mitarbeiter> mitarbeiter;

  //getter und setter ...

5. Hibernate @ManyToOne references an unknown entity

I am receiving the following Hibernate Exception: @OneToOne or @ManyToOne on Matchup.awayTeam references an unknown entity: Team The simplified Matchup class looks like this:

@Entity public class Matchup implements Serializable 
   protected ...

6. @Column(s) not allowed on a @ManyToOne property

I have a JPA entity with a property set as

private Licensee licensee;
But when I deploy on JBoss 6 the application throws an error saying:
org.hibernate.AnnotationException: @Column(s) not allowed on a ...

7. Would it be possible to just expose the foreign key instead of the entire object in a @ManyToOne interface

@Entity public class Organization {}

@Entity public class User {
    Organization org;
The @ManyToOne interface in the above code is modeled as "Organization org", even though ...

8. How to make a @ManyToOne field mandatory in JPA2?

I am designing the persistence repository for an app. I am new to Hibernate+JPA2 and I am having trouble creating more complex relationships in this case a Foreign mandatory key. An example (just ...

9. @ManyToOne JPA association and cascade... not sure what happens if I delete an object

I'm still not very clear about the way cascade works in deletion operations. I was wondering what happens if I have this:

class myBean{

    @ManyToOne(fetch = FetchType.LAZY, cascade = ...

10. Hibernate JPA2 @ManyToOne(optional=false) didn't work.

I build app basic on Hibernate JPA2 + Spring. My problem is that parameter optional won't work for me. I have next entities:

@Table(name = "person", catalog = "test")
@AttributeOverride(name = "id", column ...

11. @ManyToOne mapping doesn't work with joined inheritance

I have the following database structure:

CREATE TABLE `author` (
`id` int(10) unsigned NOT NULL AUTO_INCREMENT,
`name` varchar(255) NOT NULL,
`email` varchar(255) NOT NULL,
`password` varchar(255) NOT NULL,
 PRIMARY KEY (`id`));

CREATE TABLE `message` (
`id` int(10) unsigned ...

12. @ManyToOne relationship,JPA

I have a bidirectional many to one relationship. When I retrieve the parent object from the table, all the child objects should get retrieved but only the first one is getting ...

13. @ManyToOne + delete operation leads to "not-null property references a null or transient value" error

I have a hibernate-mapped data structures and there is an error when I try to delete it.

@Table(name = "TYPE")
public class Type {
    private int ...

14. @ManyToOne(updatable=false) - how it should work?

I want to have a read-only functionality in one of my entities. I know that in JPA 2.0 we don't have such functionality per se. I thought we can achieve it ...

15. JPA @ManyToOne

Hi evryone, I have two entity SupportingDocument n <====> 1 SupportingDocumentType @Entity @Table(name="T_COR_SUP_DOC") public class SupportingDocument{ @Id @Column(name="ID") @GeneratedValue(strategy=GenerationType.AUTO) private Long id; @Column(name="REGISTERY_KEY") private String registeryKey; @Column(name="SUP_DATE") private Date date; @Column(name="STATE_CD") private String stateCd; @Column(name="SUP_COMMENT") private String comment; @ManyToOne @JoinColumn(name = "DOC_TYPE_CD", nullable = false, referencedColumnName="TYPE_CD") private SupportingDocumentType supportingDocumentType; @Entity @Table(name="T_COR_SUP_DOC_TYPE") public class SupportingDocumentType { @Id @Column(name="ID") @GeneratedValue(strategy=GenerationType.AUTO) private Long id; ...

16. org.hibernate.MappingException: Could not determine type for:... with @ManyToOne

I have problem with @ManyToOne which generate that exception: Caused by: org.hibernate.MappingException: Could not determine type for: pl.diagno.model.vo.City, for columns: [org.hibernate.mapping.Column(city)] In Person is references to City and Street. When I remove these references it works. I put in a lot of time reading many threads and finding solution but the most similar case is here: But there the problem ...

17. @ManyToOne, "on delete set null" - possible ?

Hello all, Simple scenario: I have a Person class, where each person has a House. A house itself is oblivious to persons, it's a uni-directional relationship. Code: @Entity public class Person { private House house; @ManyToOne public House getHouse() { return; } public void ...

18. @ManyToOne annotaion and fk (foreign key) duplication

No proposals? So, I think this one can be a bug, as I am absolutely sure that, if nobody says nothing, the source code is ok and it is hibernate which is corrupting the database... Anyway, sorry if I am annoying, any proposals are welcome or should open a bug? Cheers w i l l y

19. Unchanged @ManyToOne record updates version at parent update

This is in Hibernate 3.2.4 within JBoss Seam 4.2.2. I have two @Entity objects (Parent and Child) with int @Version fields. Code: @Entity public class Parent { private Long id = null; private int version = 0; private Child child; @Id @GeneratedValue public Long getId() { ...

20. @ManyToOne need to delete referenced foreign key - ERROR?

Hello I have to classes: NewsVO and FileVO, which looks like: Code: package vo; import javax.persistence.*; @Entity @Table(name="newsdb") public class NewsVO { private long id; private FileVO image; @Id @GeneratedValue @Column(name="ID") public long getId() { return id; ...

21. @ManyToOne with @JoinColumnsOrFormulas

22. [JPA+Hibernate]@ManyToOne "deleted entity passed to persist"

Hi all I have a problem with my web application(EJB3 - JPA - HIBERNATE). I have these entity: Code: @Entity public class Commessa implements Serializable { private static final long serialVersionUID = 1L; @Id @GeneratedValue(strategy = GenerationType.IDENTITY) @Basic(optional = false) ...

23. Simple @ManyToOne, why "Could not determine type"?

Newbie Joined: Wed Feb 18, 2009 5:07 am Posts: 8 I have searched quite a lot of forums and threads, Hibernate & Spring MVC. But still cannot figure out why I am encounter this exception when starting my app: Code: Caused by: org.hibernate.MappingException: Could not determine type for:, at table: usr, for columns: [org.hibernate.mapping.Column(org)] at org.hibernate.mapping.SimpleValue.getType( ...

24. Problem on EAGER and @ManyToOne

Hello everybody, I'm trying to make a select using a EAGER fetch to select automatically an association. Unfortunatly, I can't make the EAGER work, the association is getting fetched element by element. I'm using spring 3.0.1 and hibernate 3.5.0 Final (I've just migrate from 3.3.2) I'm trying to execute that select : Code: select distinct (wec) from WatchEventCriteria wec where ...

25. @ManyToOne field null when 2nd level cache enabled

Hi I've the following mapping, some Category entity: Code: @Entity @Cache(usage = CacheConcurrencyStrategy.READ_WRITE) @org.hibernate.annotations.BatchSize(size = 30) public class Category extends AbstractEntity { (..) private static final String CATEGORY_ONETOMANY_INDEX_COLUMN_NAME = "position_in_parent_children"; private static final String CATEGORY_ONETOMANY_JOIN_COLUMN_NAME = "parent_id"; @ManyToOne @JoinColumn(name = CATEGORY_ONETOMANY_JOIN_COLUMN_NAME, insertable = false, updatable ...

26. Could not determine type for:... with @ManyToOne

Newbie Joined: Wed Mar 11, 2009 7:15 am Posts: 12 I have problem with @ManyToOne which generate that exception: Code: Caused by: org.hibernate.MappingException: Could not determine type for: pl.diagno.model.vo.City, for columns: [org.hibernate.mapping.Column(city)] In Person is reference to City. When I remove this reference, it works. I put in a lot of time reading many threads and finding solution but the most ...

27. @ManyToOne noob problem

Hello, I have 2 classes that I have a many to one association. The Handler class: @OneToMany(mappedBy = "handler", targetEntity=UnitOrder.class, cascade=CascadeType.ALL) public List getUnitOrders() { return unitOrders; } The unitOrder class: @ManyToOne(cascade=CascadeType.ALL) @JoinColumn(name="armyhandler_id") public ArmyHandler getHandler() { return handler; } I want to be able to find all of the incomplete orders using a findByExample(unitOrder) method, but it does not find ...

29. @ManyToOne AnnotationException -references an unknown entity

ObjectA ObjectB ...

30. @ManyToOne as part of key

@Entity public class Race { @Id @GeneratedValue private long id; @OneToMany(mappedBy="race") private List runs; ... } @Entity public class Run implements Serializable { @Id @ManyToOne private TimedRace race; @Id private int number; ... }

31. @ManyToOne invalid identifier exception

32. @ManyToOne with entities from several SessionFactories

Greetings! I have 2 SessionFactories which references on 2 different databases. In the first database stores tables with application data. In the second database stores reference data: all available cities, streets, etc. I had created Entities for two databases, 2 SessionFactories. All works, but separately. Can I make @ManyToOne reference from Entity1 (UserAdressInfo table in the 1st database) on Entity2 (StreetReference ...

33. @ManytoOne causing transient instance - save Exception

I am doing using JPA annotations only, with Hibernate as the provider on all my Entities. I am getting a problem with my @ManyToOne relationships saying that the "object references an unsaved transient instance - save the transient instance before flushing:" here are my two classes: Code: @Entity @Table(name = "MY_CONFIG") public class MyConfig { ...

34. @EmbeddableSuperclass, @IdClass and @ManyToOne

@EmbeddableSuperclass(access = AccessType.FIELD) public class A_PK implements Serializable { @ManyToOne @JoinColumn(name = "idB") @NotNull public B b; @ManyToOne @JoinColumn(name = "idC") @NotNull public C c; ...

35. Unidirectional @ManyToOne and Cascades

Hi, I am using hibernate-3.1.2 and hibernate-annotations-3.1beta8 with hsqldb-1.8.0. In my OO I want to have (let's say) class X, class Y, and class Association, which explicitly represents the many-to-many relational association between entities X and Y. I want the navigability to be unidirectional from Association to X (and Y), so there is not reference from X (Y) to Association So ...

36. @ManyToOne and Cascade not working, why?

Beginner Joined: Fri Apr 09, 2004 12:47 pm Posts: 36 The problem is that I have a ManyToOne with cascades specified, but cascades don't seems to work at all. Hibernate complains the associated object is transient instead of cascading the insertion. Details follow: Hibernate version: 3.2 cr1 and annotations 3.1 beta9 Mapping documents: @Entity @Table(name = "SCHEMATIC_TYPE") public class SchematicType implements ...

37. @ManyToOne cascades merge to parent when I don't want it to

Author Message apill Post subject: @ManyToOne cascades merge to parent when I don't want it to Posted: Thu Jul 13, 2006 10:21 am Newbie Joined: Fri Feb 10, 2006 6:02 am Posts: 15 I have a parent class (called MasterProduct) that has a OneToMany relationship to a set of children (class called Variant). The mapping of the objects if ...

38. @ManyToOne with invalid foreign key

39. optional @ManyToOne

Greetings! Could someone help me with this, please? I have a very simple unidirectional many-to-one (an Member knows its Freelancetype). The type information should be optional e.g. when loading Member, Freelancetype should be either null (no PK-FK match in DB), or fully loaded. Instead when PK-FK match fails, I get non-null member. getFreelancetype(), where Freelancetype returned has null fields (including freelancetypeid). ...

40. Problem with @ManyToOne Eager Association

I am trying to to an eager join fetch of a ManyToOne association using session.createQuery("from OrigemVO obj").list(), but that always executes a select fetch type. usin session.createCriteria(OrigemVO.class).list() works, but I think that is an Hibernate bug. I opened an issue in but that was rejected. Can anyone help me ? I cant use Criteria in my code because it is ...

41. Does @Cascade(CacadeType.DELETE) work with @ManyToOne?

Hibernate version: Core 3.2.5, Annotations 3.3.0 I have a simple pair of parent and child classes where the child has a reference to the parent in a @ManyToOne relationship as show below. I implemented a Cascade Delete using the @OnDelete(OnDeleteCascade.DELETE) annotation and it works fine. I would like to be able to deploy this change to older installations where this annotation ...

42. @ManyToOne - delete value in column

hi this is part of my User class: //////////////////// Code: @Entity @Table(name = "xxx.yyy.[User]") @org.hibernate.annotations.Entity(mutable = true) @BatchSize(size = 50) @Cache(usage = CacheConcurrencyStrategy.READ_WRITE) public class User { .. private Cluster cluster; .. @ManyToOne(fetch=FetchType.LAZY) @JoinColumn(name="clusterId") @LazyToOne(LazyToOneOption.PROXY) ...

43. PropertyValueException from @ManyToOne with nullable=false

Hi I have two very simple objects "Main" and "Sub" mapped using two unidirectional mappings (Main -> Sub @OneToOne and Sub->Main @ManyToOne) as can be seen from the classes below. Creating a Main object and attaching a Sub-object to it and trying to store it results in a org.hibernate.PropertyValueException (not-null property references a null or transient value: Sub.main) when the Sub->Main ...

44. PropertyNotFoundException with @ManyToOne

With the following two classes I am getting the exception: PropertyNotFoundException: field [club_id] not found on com.bill.googlemaps.domain.Location I am sure it is a newbie problem but this newbie is stuck. Any thoughts greatly appreciated. Code: Caused by: org.hibernate.PropertyNotFoundException: field [club_id] not found on com.bill.googlemaps.domain.Location at at at ...

45. @ManyToOne with PrimaryKeyJoinColumn

I'm trying to get around this lazy one to one loading issue using many to one. @ManyToOne( cascade = CascadeType.ALL, fetch = FetchType.LAZY, optional = true ) @PrimaryKeyJoinColumn( name = "X_ID", referencedColumnName = "X_ID" ) Now, I don't have another column I can use to act as a join column for this specific entity and I have no control over the ...

47. @ManyToOne not insert collected object

Author Message praedos Post subject: @ManyToOne not insert collected object Posted: Tue Sep 16, 2008 4:03 am Newbie Joined: Mon Sep 01, 2008 3:41 am Posts: 19 Hi, I have a ManyToOne relation. When I try to insert a row in the table hibernate trows that the ID of the reference object is null. ORA-01400: cannot insert NULL into ...

48. @ManyToOne mapping into View

@ManyToOne(fetch=FetchType.LAZY) @JoinColumns({ @JoinColumn(name="STUDENT_PARTY_ID", referencedColumnName="PARTYID"), @JoinColumn(name="EDU_INST_ID", referencedColumnName="EDUINSTID"), @JoinColumn(name="PROGRAMME_ID", referencedColumnName="PROGRAMID"), @JoinColumn(name="INTAKE_ORG", referencedColumnName="INTAKEID") }) public StudentView getStudentView() { return studentView; }

49. lazy @ManyToOne on fk to non pkey

HI I have a problem with lazy loading on @ManyToOne association mapping to unique (non primary key) column. I've been looking in reference guide and in Hibernate in action but still missing something. I have unidirectional ManyToOne mapping :EventLog to EventLogType Code: @Entity @Table(name = "event_log") @SequenceGenerator(name = "seq_evl", sequenceName = "sq_evl_id") public class EventLog{ @Id ...

50. lazy @ManyToOne fk to non pkey

HI I have a problem with lazy loading on @ManyToOne association mapping to unique (non primary key) column. I've been looking in reference guide and in Hibernate in action but still missing something. I have unidirectional ManyToOne mapping :EventLog to EventLogType Code: @Entity @Table(name = "event_log") @SequenceGenerator(name = "seq_evl", sequenceName = "sq_evl_id") public class EventLog{ @Id ...

51. @IdClass with @Ids pointing to non-primitive @ManyToOne

Hi, I'm trying to use @IdClass as composite key. But a lot of example used @IdClass pointing to a class with simple entities. Consider the following: Code: @Entity @IdClass(AssignedRoleId.class) public class AssignedRole { @Id @ManyToOne private User userId; @Id @ManyToOne private Role roleId; private ...

52. @ManyToOne persisting problem

hello, In my apllication, there are students and classes. a student can take many classes. So there is OneToMany <--> ManyToOne relationship. Im my case, the best implementation is using a join table. I followed examples I found on internet and at books. So I wrote the code (summary) below.. class Class: @Id @GeneratedValue @Column(name="CLASS_ID") private Integer id; private String name; ...

53. Lazy initialization does not work with @ManyToOne

Hi, I found where the problem was (for anyone that might be interested). My pojos where like this: @Entity @Table(name="COUNTRIES") public class Country { @Id private Long id; @Column(nullable=false) private String name; private final getId(){ return id; } private final getName(){ return name; } } If you pay attention you'll notice that the getters are FINAL. I was using a tool ...

54. @ManyToOne w/ discriminator? Need join tbl w/ 2 IDs + type

Hello All, I have a relationship I need to model. I wanted to have a join table with 3 IDs and ManyToOne and OneToMany annotations. Code: create table folder( id primary key ); create table document( id primary key ); create table type( id primary key ); create table folder_document( ...

55. Unidirectional @ManyToOne and Automatic Inner Joins

I have 2 entities. EntityOne has a @ManyToOne association with EntityTwo. EntityTwo has no association with EntityOne. This query "select e from EntityOne e where e.code = 'ABC'" results in two queries: one for EntityOne and another for EntityTwo. How can I force an inner join without having to specify it in the query?

56. Remove fails with @ManyToOne aggregation

Hello, Hibernate 3.3 EntityManager & Annotations 3.4 We have the following entities: Code: @Entity public class A { @Id private Long id; @OneToMany(mappedBy = "a", cascade = ALL, fetch = LAZY) @Cascade(DELETE_ORPHAN) private List bList = new ArrayList(); } @Entity public class B { @Id private Long ...

57. [solved] @Id with @ManyToOne, and shared columns

For future users, here is the solution. One, @IdClass does not permit relations, just like the JPA spec says, so use @EmbeddedId Two, use @JoinColumns on the non-id field to name the column that should be shared. However, you'll have to use insertable=false, updatable=false, so it's a read-only relation. Three, create a new field that will be mapped with the same ...

58. Mapping : @ManyToOne of a specific entity field