Hello,


I have an object of type A which is composed of an object of type B. Type B contains two collections, both of which are mapped with lazy load.

I have a mapper for A and a mapper for B, but there is a slight difference. When dealing with objects of type A, the information in B (including the collections) gets mapped to a different table than if B were mapped alone. So, when mapping A, the B component of A and its associated collections are mapped to table X.

Now, the mapper for B (i.e. if B is mapped by itself), puts the information in table Y.

Here's the problem:

I create an object of A:
openSession
session.save(a)
closeSession

then, I later pass the object of A over a queue which then extracts and saves B:
b = a.getB();
openSession
session.save(b)
closeSession

What happens here is that Hibernate deletes the collections from table X (which is mapped from A), and then inserts the collections into table Y (which is mapped from B). However, I want the data to be in both X and Y (i.e. do not delete from X).

This can be solved if I can completely detach A, filling in all lazy loaded data, etc. However, I don't see how this is possible with Hibernate.

Any help is appreciated!

Can anyone help in this question? If it is confusing, please let me know and I'll try to clarify it. This is a major problem for us with Hibernate.

Here's a more concrete example:

OrderRequest contains a Part and a Part contains a collection of Piece

We want all data in an OrderRequest (including all of the Part information) to be in a requests table. We then want to have a master Part table as well, but we don't want the data to be shared. So, the OrderRequest mapping file maps everything into one set of tables, and the Part mapping file maps everything into another set of tables (OrderRequest does not delegate the mapping of a Part to the Part mapping file).

Now, an OrderRequest comes in and we persist it. This works fine.

Later on, we decide we want to put the Part and its Piece collection into a master table. So, we extract the Part object from the OrderRequest and then call save on it. We want the data to be copied from the original OrderRequest Part object into the master tables. We don't want to delete the information from the OrderRequest tables. However, Hibernate decides to delete the collection from the OrderRequest tables and add it to the master tables.