I wonder if the following would be good:
A flag would be marked True if there has been an auto-migration.
Then you could check if a change has happened and fix items in your
database, but not need to search every time a page is run.
For example, if there are items that have a None and now need to have a
default value from a list.
db.foo.bar.requires = IS_IN_SET([1,2,3,4])
This would make an new field have None for all existing records. That's
not good, I would like:
if db.foo.bar.feild_changed:
#run my script
pass
BR,
Jason