- Using delete-orphan on a many-to-many relation is deprecated.

- Using delete-orphan on a many-to-many relation is deprecated.
This produces misleading or erroneous results since SQLA does
not retrieve the full list of "parents" for m2m.  To get delete-orphan
behavior with an m2m table, use an explcit association class
so that the individual association row is treated as a parent.
[ticket:1281]

- delete-orphan cascade always requires delete cascade.  Specifying
delete-orphan without delete now raises a deprecation warning.
[ticket:1281]