Maybe your government doesn't goof up social security numbers, but ours does. :-)
http://www2.nbc4i.com/news/2010/dec/06/2/study-finds-millions-duplicate-social-security-num-ar-316988/ Also, don't forget that if a social security number (let's assume the government never messes up and assigns the same number to multiple people) is entered by hand and is used as a natural primary key, there is a non-zero chance that the person entering the number will mistype it and you've just messed up your keys and have a mess to clean up. mrg On Wed, Apr 4, 2012 at 5:32 AM, Aristedes Maniatis <a...@maniatis.org> wrote: > Yes a government tax number or social security number is unique and > immutable. And that would be true only if your database table was a table > representing social security numbers. Instead it probably represents > 'people' and then the correlation becomes far less certain. Do government > departments ever make mistakes? Do they reassign numbers to people in a > witness protection program?
