We are trying to apply the composite pattern to an Entity which has a composite ID.

(For the purpose of this question, please assume that we cannot use surrogate keys)

Please consider the following:

Entity Parent has composite-id A,B
Parent can have many children of type Parent

Question:

Could someone demonstrate how to map this type of association? We currently have an association table representing the many-to-many relationship. If not using a surrogate key, we design this table with a four column foreign key and our attempts at mapping the many-to-many collection from the parent Entity have failed.

We've sifted through the forum and understand all to well the argument regarding surrogate keys from the Hibernate Team. However, we'd appreciate if someone could describe how to map this relationship correctly without the usage of a surrogate key (if at all possible).

Regards,
Roll

Sorry where it reads "we design this table with a four column foreign key" I intended to write "we design this table with a four column composite key".

Something like:



And yes, this is all covered in the docs http://www.hibernate.org/hib_docs/reference/en/html/components.html#components-compositeid

"messy" indeed.

Cheers,
Roll