- `surname` - `birthdate` - `wife_id` (foreign key references column `females`.`id`, may be NULL if male is unmarried) `females` - `id` - `forename` - `surname` - `birthdate` - `husband_id` (foreign key references column `males`.`id`, may be NULL if female is unmarried) Friday, March 15, 13
- `birthdate` - `wife_id` (unique foreign key references column `females`.`id`, may be NULL if male is unmarried) `females` - `id` - `forename` - `surname` - `birthdate` Friday, March 15, 13
- `birthdate` - `wife_id` (foreign key references column `females`.`id`, may be NULL if male is unmarried) - `marriage_date` (may be NULL if male is unmarried) - `divorce_date` (may be NULL if male is unmarried or married but not yet divorced) `females` - `id` - `forename` - `surname` - `birthdate` Friday, March 15, 13