I don't think HFEJB got into it too deeply, but I do think that for CMP beans, someEBObjectWithRelationship.remove(someEBObjectInRelationship) on an entity bean actually removes it from the database. Of course if you are just spinning through a collection of non-EB's, and you run remove it's not going to do anything to the database.
The examples are horrific (with A's and B's, 1's and 2's)* but this page goes into it very extensively.
* I had to re-write the examples with John, Paul, George and Ringo related to various instruments before I could really 'see' the relationships. [ May 15, 2004: Message edited by: Dale Seng ]