Re: identity columns

From: Ben Clifford <>
Date: Thu, 03 Jan 2002 20:52:11 GMT
Message-ID: <>

Alan wrote:

> For people in the U.S., SSN is generally a perfect PK. Yes, there have been
> duplicates issued by the SSA, but they are extremely rare, and if your
> universe of people is known (i.e., not potentially anyone, but rather a
> company's employees), then SSN is the way to go. If you should happen upon a
> duplicate, change the first character to an A. If this happens, you'll need
> another column that contains the true SSN for tax reporting purposes.

It is possible to employ someone who has no SSN - eventually they will get an SSN but possibly not for several months.

This means that you possibly have to make up a fake ID string for them and deal with the consequences later - eg. human operators being unable to cope with the ID not being the persons SSN.

Or you have to not put them in the database for several months, which means that the benefits of the database are not provided for that employee (presumably there are some benefits associated with being in the database, either for the employee or employer - otherwise, there is not much point in having the db in the first place)

And for people who wish to wrangle on law, a system so designed would (indirectly) prejudice against immigrants and so may be in violation of US Federal Law, I think. Although pretty much everyone discriminates in this way and seems to get away with it.

Ben Clifford  GPG: 30F06950
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Received on Thu Jan 03 2002 - 21:52:11 CET

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