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

Karsten Farrell <kfarrell_at_belgariad.com> wrote:
> Galen Boyer wrote:
> > On Mon, 18 Nov 2002, kennedy-family_at_attbi.com wrote:
> >
> >
> >>a surrogate key is an arbitrary key (eg a sequence). A natural
> >>key is one that is naturally part of the data (eg in the US the
> >>social security number for people)
> >
> >
> > But the social security number was a generated number. Sure,
> > mine "means" me, but it was still generated.
> >
> > Maybe part of the arbitrary argument can be upheld because a
> > person designing his database doesn't trust "natural" keys. Most
> > database guys aren't, and shouldn't be, very trusting of much.
> >
> Well, it might be different now ... but when I got my SSN (admitedly a
> very long time ago), the first 3 digits indicated what region of the
> country you were in when you applied for one. The fact that it has that
> wee bit of "smarts" designed into it makes it a natural key. It's not a
> truly generated key ... except maybe within the region.

That's the same as for OPS when you use CACHE and NOORDER. Each local 'office' gets a chunk of numbers from which it allocates without refering back to the central office. The only difference being how large those chunks are and how many offices there are. Do you consider Oracle sequence numbers to be natural for this reason?

> I know some people who know some people who will, for a small fee,
> produce a "legal" Social Security Card with a unique SSN.

Do all the people who do this coordinate with each other and the government? If not, how can they know that the number is unique? I bet you get a card which they hope is unique.

> Don't know
> where they hijack the numbers from, but it's enuf to fool the IRS. All
> this tells me the SSN is not an arbitrary key.

I know people who know people who can get a legal PK, which is good enough to fool a database into accepting it. Does that mean Oracle PKs assigned from a sequence number are not arbitrary keys?

Xho

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