fetch="join" ignores lazy property?

Thies · **Joined:** Mon Jan 17, 2005 8:11 pm **Posts:** 1

On a mapped collection it seems fetch="join" ignores the lazy property and does indeed initialize the collection when the parent object is created.

For instance (on Hibernate 3.1.3):

mapping:

Code:

<class name="Parent">
..
<set name="children" inverse="true" fetch="join"  lazy="true">
..

DAO (via spring):

Code:

return (Parent) getHibernateTemplate().get(Parent.class, new Long(id));

The resulting query is:

Code:

..
 FROM Parent LEFT OUTER JOIN child child1_ ON etc. etc.
..

Now it shouldn't fetch the child by default, only when I access the property in the session right? The problem isn't performance but later on in the same session I get a

Code:

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

is this a bug or am I overlooking something?

damnhandy · **Posted:** Fri Aug 11, 2006 9:14 am

When you join any relationship, the query includes the data for both the parent and child object, which disables lazy-loading. This is covered in the "tuning fetch strategies" section of the docs:

http://www.hibernate.org/hib_docs/v3/re ... ing-custom

You simply cannot have lazy-loading working with a joined relationship.

Ryan-[/quote]