Duplicate names and birth dates
Ken Sheridan, long time resident of the Microsoft Access newsgroups, posted a very interesting paragraph in a thread title Duplicates
A year or so ago I witnessed a remarkable coincidence when attending a hospital clinic. Two patients, both female, both with the same date of birth and both with the same names were attending. I happened to overhear the staff talking about it and it appeared that the 'key' used for identifying patients was a combination of name, gender and date of birth, so the staff were having difficulty distinguishing the medical notes of one from the other. One wonders what might have happened if they hadn't spotted the problem!
My brother, who shares my last name Toews, has a very troublesome time whenever stopped by the police, which seldom happens, or whenever he crosses the border into the U.S.A. Turns out he has the same first, middle and last name and birth date with a Canadian who has a lengthy criminal record. My brother now adds an hour to his estimated border crossing times. Although his last crossing they must've had a photo of the bad guy. He was being interrogated in a side room when another US Border guy came in and told them that it was someone else.
Of course then there's George Foreman's five boys named George.
The point to my posting being that you can't use name and birth date as a unique key. This also goes for corporation names. There could conceivably be duplicate names in provinces and states as these are usually provincially/state incorporated. Also if you are dealing with different branches of the same company you will likely want to include city and province in your inquiry screens.