DA Morgan wrote:
> joel garry wrote:
>
> > Agree with natual/surrogate post by Daniel - except, SSN is not
> > guaranteed unique! (The problem really being insufficient analysis of
> > natural keys).
> >
> > jg
> > --
> > @home.com is bogus.
> > http://dizwell.com/migforum/index.php?topic=189.0
>
> SSN is in most situations. It certainly meets the needs of insurance
> companies. But you might want to do a two-field PK with SSN and DOB.
>
> I like to use it because (A) I've never seen a duplicate and (B) if I
> saw one I'd like it to generate an error so I could call security.

>From http://www.ssa.gov/regulations/artic...960_ag25f.htm: "We
anticipate that the three-card per year limit will impact fewer than
10,000 individuals in any given year. For example, of the nearly 12.4
million replacement SSN cards we issued in 2004, the number of
individuals who requested more than three replacement cards was 3,818."

Gee, now why would thousands of people need more than 3 replacement
cards in a year...?

Of course, there are also situations (generally, government) where
people may refuse to give their SSN. See
http://www.epic.org/privacy/1974act/ (and search for the word "index"
for an odd fact about whether SSN is indexed or not).

Things may change:
http://news.com.com/Congress+may+sla...l?tag=nefd.top

One-to-many:
http://www.ssa.gov/oig/ADOBEPDF/audi...8-00-10047.htm

(I can't seem to find the duplicate ssn links among all the
anti-gummint craziness in the minimal time allotted. But of course if
two people refuse ssn's on religious grounds, you have to deal with
that somehow).

jg
--
@home.com is bogus.
http://www.fincher.org/Misc/humor.shtml