BC dates and date validation
At the moment it's not possible to enter BC date. It would be good if dates back to -4713 (PostgreSQL timestamp limit) could be entered.
Update: Solved BC dates using the numpy library. There are some changes:
- year values possible from 4173 BC to 9999 AD
- missing values are substituted with 1 (e.g. if only the year 2018 was entered it becomes 2018-01-01)
- extensive date validation was added (e.g. a begin date cannot be after an end date)