Normaly I would implement a cascade delete as follows:
class Wiki(SQLObject):
pages = MultipleJoin('Page')
...
def delete(self):
"Ensure referential integrity explicitly without using DBMS
constraints."
for page in pages:
page.delete()
self.destroySelf()
class Page(SQLObject):
...
def delete(self):
"Nothing here yet"
self.destroySelf()
There is also a cascade option for ForeignKey columns build into
SQLObject but it doesn't seem do anything with MySQL. Good luck with
your wiki.

