Unexpected updates when selecting a parent with a collection

yaq2 · **Joined:** Mon Dec 10, 2007 10:21 am **Posts:** 4

Hi,

I am getting unexpected Update statements when doing simple selects.

It only occurs on one-to-many relationships.

For example, I do a hibernateTemplate.get(class, id) on the parent object. When the session commits, I notice a whole bunch of update statements being run on the children.

It happens on all of our parent-children classes.

Obviously something is getting changed and Hibernate is rightly detecting it, then doing the update. But I can't figure out what is making the change.

Doing a direct get/select on the child does not cause updates, so I don't think it's a problem with the getters/setters on the individual class.

The mapping looks like:

Code:

private List<SkuOptionDO> skuOptionList = new ArrayList<SkuOptionDO>();

       @OneToMany(mappedBy = "skuType", cascade={CascadeType.ALL})
   public List<SkuOptionDO> getSkuOptionList() {
      return skuOptionList;
   }
   public void setSkuOptionList(List<SkuOptionDO> skuOptionList) {
      this.skuOptionList = skuOptionList;
   }

Any ideas what could be causing the updates on the collection?

Thanks.

Hibermate 3.2.0
Java 1.5.0_11
MySQL 5.0

yaq2 · **Joined:** Mon Dec 10, 2007 10:21 am **Posts:** 4

I am now part way to solving the mystery.

We have a class that extends DefaultSaveOrUpdateEventListener, that overrides public void onSaveOrUpdate(SaveOrUpdateEvent event).

The method is supposed to be called whenever a Save or Update is about to happen and set the audit fields (created and updated timestamps).

For some reason, this method is getting called when the session/transaction commits on a hibernateTemplate.get(class, id).

Of course, then the timestamps are changed at it has to do an update.

If I take the listener out of the config, no update SQL shows up.

So the new question is:

Why is the DefaultSaveOrUpdateEventListener.onSaveOrUpdate(SaveOrUpdateEvent event) method being called when the session commits at the end of a hibernateTemplate.get(class, id) call?

And why does it only happen on objects in a collection?

Captain Ramen · **Joined:** Thu Jun 28, 2007 7:30 pm **Posts:** 7

Oddly enough, I ran into the exact same problem today. I fixed it by changing Session.FlushMode from Auto to Commit. I have already made sure I do database modifications in a transaction, and explicitly call Commit when I am done.

I think it is when you lazy load a collection. The version is changed after the collection is populated, although it probably shouldn't be.

harshalx · **Posted:** Wed Feb 13, 2008 3:50 am

Hello
I am facing the same problem and unfortunately I don't think that setting the Session FlushMode as COMMIT is a good solution. Our Sessions are returned from a SessionFactory managed via Spring. Each DAO class gets a current Session Obj for itself and fires queries. The Session FlushMode is AUTO by default and hence there is no need to call a commit.

Does anybody have a better solution?

harshalx · **Posted:** Mon Feb 18, 2008 9:43 am

I finally found a temporary workaround.

Before your select query fires do a

Code:

org.Hibernate.Query query = createYourQuery();
query.setReadOnly(true);

Thats does it.

juersimon · **Posted:** Mon Feb 18, 2008 11:56 am

I have the same problem with annotations and entityManager. But only when I use a EntityTransaction. When I commit the EntityTransaction I get these updates. When I don't use EntityTransactions everything works fine!?!?