Suppose I have this:

<many-to-one
name="foo"
class="com.package.foo"
cascade="none"
outer-join="auto"
update="true"
insert="true"
column="foo_id" />

is there a way for Hibernate to get the actual value of the foo_id, rather than the foo object without also adding a seperate <property> for the foo_id value in the mapping file? I don't want to have to load the foo object just to get its id.

No. If there is no java property mapped to it, you can't get it.

Note that you can proxy the foo class. Thus hibernate won't load foo if you just get id.

Or use a HQL query with projection to the ID. See http://www.hibernate.org/hib_docs/reference/html/query-language.html#query-language-s5

Cheers.