That can happen if you are using unidirectional associations.However, unidirectional associations don't perform very well even from an SQL perspective.

However, I'm interested in seeing a replicating test case for this statement:

Making all the relationships bidirectional optional @OneToMany relationships seems to reduce but not eliminate the use of UPDATEs.

Because I don't recall ever seeing that for @ManyToOne or bidirectional associations.