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I have tables named Country, City and People. What can I prevent hibernate to save same people object? Here is my classes and the problem is when I try to save a country object, Hibernate tries to save or update same people objects as expected.(City's people object and Country's people object has same PK)

org.hibernate.NonUniqueObjectException: a different object with the same identifier value was already associated with the session

Classes;

class Country{

.....

@JoinColumn(.....)
@ManyToOne(optional = false, fetch = FetchType.EAGER)
@Cascade(org.hibernate.annotations.CascadeType.SAVE_UPDATE)
private City city;


@JoinColumn(.....)
@ManyToOne(optional = false, fetch = FetchType.EAGER)
@Cascade(org.hibernate.annotations.CascadeType.SAVE_UPDATE)
private People people;

}

class City{

....

@JoinColumn(.....)
@ManyToOne(optional = false, fetch = FetchType.EAGER)
@Cascade(org.hibernate.annotations.CascadeType.SAVE_UPDATE)
private People people;

}

Here is my save method;

public void save(){

    ....


    getCurrentSession().saveOrUpdate(customer); //Hibernate session


 }
hellzone
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1 Answers1

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2 solutions here :

  • Use merge instead of save
  • or remove save cascade annotation.

Using both save and save cascade basically tells Hibernate "please persist this new object along with all his relationships which are also new". You don't want that.

KeatsPeeks
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  • Changing @Cascade(org.hibernate.annotations.CascadeType.SAVE_UPDATE) to @Cascade(org.hibernate.annotations.CascadeType.MERGE) is enough? I don't know what merge really does. – hellzone Mar 04 '14 at 09:29
  • See http://stackoverflow.com/questions/170962/nhibernate-difference-between-session-merge-and-session-saveorupdate => "You should use Merge() if you are trying to update objects that were at one point detached from the session, especially if there might be persistent instances of those objects currently associated with the session. Otherwise, using SaveOrUpdate() in that case would result in an exception." – KeatsPeeks Mar 04 '14 at 09:42