Dear all,

I have come across a problem which I was puzzled and need some help. I have a biz transaction table name "A" that reference a master table e.g. Country.


@Entity
public class A {
@ManyToOne(fetch=FetchType.LAZY)
@JoinColumn(name="COUNTRY_CODE",insertable=false,updatable=false)
private Country country;

@Column(name="COUNTRY_CODE")
private String countryCode;
...

@Entity
public class Country {
// no one to many association for A defined
...


Using entityManager.find(A.class, pk) to retrieve A entity instance allow me to lazy load my Country reference simply with a.getCountry().toString();

Whenever i have a detached A entity instance to be updated, I simply do:

A managedA = entityManager.merge(detachedA).

However, the instance returned: managedA doesn't trigger lazy loading of my country reference when i do managedA.getCountry().toString(); The country reference will always return null.

I have tried with entityManager.flush(); after the merge() operation and yet it still return null country reference. I was even puzzled further when i replaced flush() with entityManager.find() after the merged() operation, result remained the same with further disappointment.

I am not sure whether this is a problem of hibernate or is my approach to tackle this problem wasn't correct. Need some advice from fellow experts. Thanks in advance.


Hibernate version: 3.2.6.ga

Did you find solution about that ? I'm facing to the same problem, i can't load the entity B in relation with the entity A when the fetch type is LAZY, when it's EAGER i can obtain it, but I don't wan't to put all my relation on EAGER...

So someone has a link to redirect for the solution ? (I'm using Spring which manage my entities jpa)

thanks

Hi,

If country of detached A is null, merge will delete this association. Did you load country before A became detached? If A is a detached entity, its state is copied into existing managed instance A.

Cheers

G

Try changing the annotation for country

from

@ManyToOne(fetch=FetchType.LAZY)

to

@ManyToOne(fetch=FetchType.LAZY, cascade=CascadeType.MERGE)