Postgres has a handy feature called generated columns. These are columns that can only be read but not be written.
Unfortunately they don't seem to work with Jennifer at the moment
(omitting them from the mapping doesn't work, neither does marking them as virtual).
Maybe it's possible with a custom converter?
(is there a way for a converter to completely strip the column from updates and inserts?)
Otherwise it would be nice to have support for readonly-columns at some point.
(not urgent for my use-case - just a "nice to have" feature request)