parent->child->grandchild results in too many child ob

giles · **Joined:** Mon Jul 18, 2005 12:45 pm **Posts:** 4

I have create a simple set of objects like:

Code:

class Parent{
...
@OneToMany(mappedBy="parent", fetch=FetchType.EAGER)
@OnDelete(action=OnDeleteAction.CASCADE)
@Cascade(value={CascadeType.ALL, CascadeType.DELETE_ORPHAN})
public List<Child> getChildren() ..
...
}

class Child {
...
    @ManyToOne()
    @JoinColumn(name="PARENT_ID", nullable=false)
    public Parent getParent()
...
    @OneToMany(fetch=FetchType.EAGER, mappedBy = "configParam")
    @OnDelete(action= OnDeleteAction.CASCADE)
    @Cascade(value={CascadeType.ALL, CascadeType.DELETE_ORPHAN})
    public List<GrandChild> getGrandChildren()

}

class GrandChild {
...
@ManyToOne()
    @JoinColumn(name="CHILD_ID", nullable = false)
    public Child getChild()

}

I then build a structure like:
--parent1
----child1
------grandchild1
------grandchild2
------grandchild3
(so, 1 parent, 1 child, 3 grandchildren)

Saving this structure works fine, and the db is correct. The issue is when I load a parent object it has 3 children instead of 1. Each child has the correct 3 grandchildren, but there should be only 1 child not 3.

The generated SQL looks fine, and there are 3 populated rows as you'd expect. I thought it might be an issue with .equals on the child, but I think it's fine....

Any help is greatly apprecitated!

alesj · **Posted:** Wed May 03, 2006 4:49 am

What's this 'configParam'?

@OneToMany(fetch=FetchType.EAGER, mappedBy = "configParam")

giles · **Joined:** Mon Jul 18, 2005 12:45 pm **Posts:** 4

That was left over from my real domain model. I changed the names of the objects to parent, child, grandchild in this example. child was named configParam and grandchild was configParamChoice. But it doesn't change the behavior.

@OneToMany(fetch=FetchType.EAGER, mappedBy = "configParam")

should have been:

@OneToMany(fetch=FetchType.EAGER, mappedBy = "child")

BTW, I changed the Parent to have a set of children instead of a list and the problem went away. I assume this is just hiding the issue.

alesj · **Posted:** Wed May 03, 2006 12:02 pm

Quote:

BTW, I changed the Parent to have a set of children instead of a list and the problem went away. I assume this is just hiding the issue.

This is expected behaviour, since Set is a set after all :-).

Are you sure you get 3 Child instances?
How is it with List and its index?
Since if the Set merged your Child instances, you could be getting a single instance, but positioning it on the wrong index.

emmanuel · **Posted:** Thu May 25, 2006 2:18 pm

do not eager more than one bag semantic connection

giles · **Joined:** Mon Jul 18, 2005 12:45 pm **Posts:** 4

I'm using List semmantics not Bag. Is there some way to get that to work? thanks.

solomonk · **Joined:** Tue May 30, 2006 9:45 am **Posts:** 5

I also have exactly the same table's structure parent->child->grandchild and with eager one-to-many associations also get too many grandchild and child objects.. in debug mode I so, that that lists was filled by duplicated (equals by reference) objects, so I just replaced Lists collections with Sets and Maps and problem is gone..