org.hibernate.TransientObjectException Revisited
This is continuation of my earlier post on org.hibernate.TransientObjectException. Let me write the scenario again
<class name=”com.xxx.A” table=”A” schema=”TESTSCHEMA”>
<id name=”aId” type=”java.lang.Long”>
<column name=”A_ID” precision=”29″ scale=”0″ />
</id>
…………………..
some more mapping elements
…………………..
…………………..
<many-to-one name=”bId” class=”com.xxx.B” fetch=”select”>
<column name=”B_ID” precision=”29″ scale=”0″ />
</many-to-one>
…………………..
A is referring to B using a primary key column of bId of B.
In that post I have mentioned that if B is a transient object and you don’t want to persist the value of B to A then just tell the hibernate to ignore that value by saying
update=”false” insert=”false” in the many to one mapping.
But what if you want to persist the value of foreign key in A.
Then the approach is different. You have to make sure that instance B is persistent not transient.
That is if your code says something like
A a = new A();
B b = new B();
a.setB(b);
…..
…..
session.save(a);
you are in trouble. Because B is in transient state. You have to attach b to the session.
There may be other ways of attaching this transient object to session. The approach I am following is simple. I am reading the value of B from the database using Hibernate. That way, hibernate attaches B to session and it is then a persistent object.
That is I do something like
A a = new A();
B b = session.get(B.class, new Long(1));
a.setB(b);
…..
…..
session.save(a);
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Hello. Thanks for visiting my blog. I am Paras Jain. I am a Riveter – team member of Rivet Logic Corporation in Reston, Virginia, USA. I am working as Senior Software Engineer. Currently most of my work involves implementing solutions involving Liferay and Alfresco. I have experience in Grails, Spring, Struts, Hibernate, JSF, JBoss Seam and many others. I am also technical owner of few websites developed in WordPress, Drupal and Prestashop. I am a Sun Certified Java Professional. You can reach me at my email id http://scr.im/parasjain01 or http://scr.im/parasjain
I’m doing just what you say, but I still get the transientobjectexception… It is very strange.
Sorry should have finished my previous post. the update=”false” insert=”false” works just fine, but why is it required when I have just loaded the value of the many to one column from the database? Should be the same sessions right? Right in the same method… And there are other very similar properties (i am initializing the same way) that don’t have the problem. That is what is strange.
what happens if A and B are new objects
that is if B is not existing in the DB.
Is there a strategy there
Hi paras,
could you help me
how to do this with JPA
A a = new A();
B b = session.get(B.class, new Long(1));
a.setB(b);
…..
…..
session.save(a);
TIA
kirti
@Niraj
If A and B are new objects, solution given here is not gonna work. You may need to apply cascade for merge in mapping.
Hello there,
For new objects, as Niraj one, I found a solution, but maybe its not the best one.
A a = new A();
B b = new B();
a.setB(b);
session.save(b);
session.save(a);
session.commit();
Well, the problem comes when I try to attach a Set to session; for each instance stored in the Set, I have to make a call to session.save(currentObject); these iteration is a really nasty way to resolve the problem, but works fine for me.
Maybe something better?
I mean, a objects Set pointed by an Object.
Thanks Jeff for contributing. I must admit that my post is a little obsolete. I will have to update it based on current hibernate version and my knowledge on that.
A bit more about this issue:
Be sure your id generator option is not set to “assigned”. If your have something like that:
…
Turn class to “increment”. If you dont, it throws this issue because the parent object has not an identifier assigned yet.
See you.
And if you want to keep generator as “assigned” then make sure you assign “unique” id to the object before persisting
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Hi Niraj..
Please use the below statements..if you are using annotations..and want to save both parent and child as new objects..
then inside the Bean of parent class use
@OneToOne(cascade = CascadeType.ALL)
above the child member..
it works.
HI All,
How can update value of b in table A with “Null”
Can any one help me out
thanks in advance.