You have to do:
1. Don't use cascade for delete on line items.
2. Create a named query containing a delete statement ( like "delete from li LineItem li where li.order =
rder" )
3. The delete method should do:
- get the instance of order
- get the named query
- set the order parameter to named query
- call executeUpdate on named query (now all items are deleted)
- delete the order