Greetings.

I have a group of parents (Foo) that have children (bars). What is the proper way to move a child from one parent to another? I currently have code that looks like this:

bar.parent = newParent;

when i try to persist this i get an error telling me that bar already exists in the tranaction someplace else. This is probably true since the old parent is indeed in the transaction by way of another one of it's children. So I am begining to think that bar.parent = newParent doesn't remove the child from the oldParent's child collection?

whats the best way to do this then? -- or am i totally wrong with thats happening?

i think my problem is related to having the same record from the database being represented as 2 distinct instances of the parent --- and they are in the same transaction...

I would need to see more detail about your transaction, however, bar.Parent does not affect parent.Bars. Indeed you have to manage the referential integrety yourself. You can either write business methods or do the work yourself in code. so, if you change bar.Parent, you would have to mange the changed to newParent.Bars and oldParent.Bars yourself.

-devon

interesting.... cause after i figured out the "multiple references of same row" problem - it worked.

The front end has a screen with all the parents and children and lets you mix them up however you want (re-assign children etc...)

I was doing something like this:

as you can see the problem with this is that GetParent returns new instances every time -- so when the second child of the same parent comes along he gets the same parent but in a different instance... now put all these children in a collection and call the manager.SaveKids(childCollection) - which does everything in one transaction and you've got problems....

ALL i did to get this to work was this:

walla - this works fine. But I never explicitly remove the child from the former parent collection - and it still works... maybe because i am persisting the children in the end with SaveKids (as opposed to SaveParents) ...

hrmmmmm