Re: Casade Persist

[Craig L Russell]

Hi JuneG,




Craig

On Dec 4, 2007, at 3:00 PM, JuneG wrote:

There's nothing obviously wrong in your example. Can you run with SQL tracing on and see if there is a difference between when it works and when it doesn't?

Craig L Russell wrote:

Hi,

I can't tell from your description what might be going wrong, but
there is one clue. You ask if all entities should be persisted in one
transaction. Not necessarily. But if you have several transactions,
it's possible that you are using detached instances and the problem
might be that if you assign an instance to a field of a detached
instance and then commit the transaction, nothing happens!

You need to make sure you merge all detached instances or nothing is
supposed to happen.

Can you attach a test case?

Craig

Thanks for your reply!


objects and then persist them in one transaction by a session bean.

and C will be saved.  what might be wrong?

@Entity
public class ClassA {

        //fields definition


= "classA")
        private Collection<ClassB> classBs = new HashSet<ClassB>();


= "classA)
        private Collection<classC> classCs = new HashSet<ClassC>();
}

@Entity
public class ClassB{

        @ManyToOne(fetch = FetchType.LAZY, cascade = CascadeType.PERSIST)
        @JoinColumn(name = "class_a_id")
        private ClassA classA;
        
        //fields defintions
}

@Entity
public class ClassC{

        @ManyToOne(fetch = FetchType.LAZY, cascade = CascadeType.PERSIST)
        @JoinColumn(name = "class_a_id")
        private ClassA classA;
        
        //fields defintions
}



@Stateless
public class SessionBean{

        @PersistenceContext(unitName = "test")
        private EntityManager em;

        public buildA{
                ClassA a = new ClassA();
                
                ClassB b = new ClassB();
                Collection<ClassB> classBs = new ArrayList<ClassB>();
                b.setClassA(a);
                classBs.add(a);
                a.setClassBs(classBs);
                
                ClassC c = new ClassC();
                Collection<ClassC> classCs = new ArrayList<ClassC>();
                c.setClassA(a);
                classCs.add(a);
                a.setClassCs(classCs);
                
                em.persist(a);
        }
}

--

here is a simple version of what we are doing. we are creating all new occasionally A&C got stored without B. if we re run the process all A, B @OneToMany(cascade = CascadeType.PERSIST, fetch = FetchType.EAGER, mappedBy @OneToMany(cascade = CascadeType.PERSIST, fetch = FetchType.EAGER, mappedBy //by default all the methods in this session bean has required tx attribute View this message in context: http://www.nabble.com/Casade-Persist- tf4946103.html#a14161450

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Craig Russell
Architect, Sun Java Enterprise System http://java.sun.com/products/jdo
408 276-5638 mailto:[EMAIL PROTECTED]
P.S. A good JDO? O, Gasp!

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