The JOIN emitted by default is a LEFT OUTER JOIN, to allow for a lead object
that does not refer to a related row. For an attribute that is guaranteed
to have an element, such as a many-to-one
-reference to a related object where the referencing foriegn key is NOT NULL,
+reference to a related object where the referencing foreign key is NOT NULL,
the query can be made more efficient by using an inner join; this is available
at the mapping level via the :paramref:`.relationship.innerjoin` flag::