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Hibernate ConstraintViolationException in join table

Answer 1

+2 A:

There are several problems with your code:

You have ids declared as Serializable instead of plain long (or Long). Why?
You should map actual Zone (or AlarmZone if you want) instances in your OneToMany relationship instead of ids. There's no need for intermediate table unless the relationship is really ManyToMany in which case it should be mapped as such (can a single AlarmZone belong to more than one Camera? If so, it's many-to-many).
You have inheritance annotation on your Camera entity. Why? Is it part of another hierarchy?
The "boilerplate" code you're using is bad. Transaction should enclose an entire unit of work, not individual entity. Explicit flushing is unnecessary.

Sample mapping:

@Entity
@Inheritance(strategy = InheritanceType.JOINED)
@Table(name = "cameras")
public class Camera {
    private long id;
    private List<AlarmZone> alarm_zones = new ArrayList<AlarmZone>();

    @SequenceGenerator(name="Camera_Gen", sequenceName="cameras_seq")
    @Id @GeneratedValue(generator="Camera_Gen")    
    public long getId() {
        return this.id;
    }

    @OneToMany(mappedBy="camera") // this maps a bi-directional relationship
    public List<AlarmZone> getAlarmZones() {
        return alarm_zones;
    }

    ...
}

@Entity
@Inheritance(strategy = InheritanceType.JOINED)
@Table(name = "zones")
public class Zone {
  // same deal as above
  ...
}

@Entity
@Table(name = "alarmzones")
public class AlarmZone extends Zone {
  private Camera camera;

  @ManyToOne
  public Camera getCamera() {
    return this.camera;
  }
}

Details on identifier mapping and association mapping.

ChssPly76 2009-10-23 21:28:14

Thanks for the tips. They're much appreciated.I definitely agree that having a list of actual AlarmZone objects is the way to go, but I don't really have enough time to make the required changes to the codebase. Do you have any idea what could be causing the exception on the join table insert?

Seth 2009-10-23 22:27:58

I don't mean to be a jerk about it but if you don't have the time to do it correctly now, how will you find the time later (when you've built more stuff upon this)? The problem with AlarmZone ids is that Long is NOT an entity; you can NOT map ids as @OneToMany. The only way to map them is via @CollectionOfElements - see 2.4.6.2.5 section of Hibernate Annotations docs for an example.

ChssPly76 2009-10-23 22:58:33

Unfortunately, there are circumstances out of my control that prevent me from doing it correctly right now (specifically, refactoring the code to enclose a full unit of work and changing the Camera class to have actual AlarmZones would take significantly more time than I have. That bad boilerplate code is strewn through the entire app).

Seth 2009-11-03 22:30:30

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Hibernate ConstraintViolationException in join table

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