When I change a table definition in db.define_table, either by dropping a field or changing a field type, the change never seems to take effect in SQL. Old columns and old field types are always retained, even though web2py seems to 'think' they've changed.
I'm using SQLite, and run into this issue repeatedly. I've posted specific details on StackOverflow: http://stackoverflow.com/q/8565024/165673
