Re: Is the use of VARCHAR(256) as Primary Keys preferred in Oracle?

Galen Boyer <galenboyer_at_hotpop.com> wrote in message news:<ulm3b1sbt.fsf_at_hotpop.com>...
> On 27 Nov 2002, Mark.Powell_at_eds.com wrote:
> > Galen Boyer <galenboyer_at_hotpop.com> wrote in message
> > news:<uwumzph80.fsf_at_hotpop.com>...
> >
> > key has to be associated to the correct business data. In examples
> > like this that association is subject to errors.
>
> Mark,
>
> I guess the SSN isn't all that great of an argument tool for the
> "natural" crowd? Do many people actually choose to use the SSN as a
> key? I would never do this because of the simple fact that there would
> be too many rules played out before the record got into the database.
> Is the "key" in a particular format?
> Does it have only numbers?
> Is there a 10th digit?
> Is it really the correct SSN number?
> ...
>
> I would rather make it so there is more than one way to identify the
> person on the end of the app, allowing for mistakes at each entry point,
> hoping they can at least remember one way in. If they do get one of
> those correct, then they get the information from the record with my
> manuafactured key.
>
> Having the key to the table be something that the user is in charge of
> defining doesn't sit well with me.

Galen, sorry about the slow response. I missed checking on my threads due to American holiday and busy days at start of month but to try to answer some of your questions.

Yes, the SSN is often used as a key on mainframe payroll/benefit systems. I do not have much experience working with these systems but back around 1992 I helped move data from one version of such a system to another and it used the 9 digit SSN as a unique key.

I talked to friend at a college and their system appends another 9 characters to the SSN for the system key, but she said they have a unique secondary index on the SSN and that is used for access for most of the time.

And importantly the the first character of the SSN may be a non-numeric nowdays. She says they have entries that start with a 'D', but she doesn't know of any special meaning being attached. She also believes that the SSN can be 10, but their system was setup years ago to handle 13 digits. I suspect someone had realized that the Social Security people were going to run out of numbers and just expected them to get bigger.

I have seen a lot of screens that use the SSN when dealing with collegs and the health insurance systems seem to use SSN as their primary means of access.

This dependence on one number, the SSN, is the main reason we have an Identify theft problem here in the US. It is an easy crime to commit.  Most consumer financial systems seem to identify the consumer by the SSN. HTH -- Mark D Powell -- Received on Thu Dec 05 2002 - 10:01:50 CST