get passive_updates=False to actually cascade

[Former user]

See #2665 for notes.

[Mike Bayer]

illustrates the issue

[Former user]

Do you have an amount you can quote that it would take to sponsor this change?

[Mike Bayer]

• reword and update documentation on passive_updates=False; as virtually all DBs now support ON UPDATE CASCADE other than Oracle, there's no need to try to reimplement more functionality here and users should be encouraged to forego natural PKs unless their target platform supports them. references #2666

→ <<cset d459afa8dbf7>>

[Mike Bayer]

• reword and update documentation on passive_updates=False; as virtually all DBs now support ON UPDATE CASCADE other than Oracle, there's no need to try to reimplement more functionality here and users should be encouraged to forego natural PKs unless their target platform supports them. references #2666

(cherry picked from commit d459afa8dbf73b8d9d620d09dede97e3461b6b3f)

→ <<cset 7de0e558e154>>

[Mike Bayer]

• reword and update documentation on passive_updates=False; as virtually all DBs now support ON UPDATE CASCADE other than Oracle, there's no need to try to reimplement more functionality here and users should be encouraged to forego natural PKs unless their target platform supports them. references #2666

(cherry picked from commit d459afa8dbf73b8d9d620d09dede97e3461b6b3f)

→ <<cset 794181697aef>>

[Mike Bayer]

most RDBMS now support ON UPDATE CASCADE, including sqlite. With Oracle being the only exception, this feature doesn't have much of a use case as natural PKs should only be pursued on backends with support for this use case.