Am Fri, 22 Oct 2004 08:33:52 -0500 schrieb Turkbear
<john.g_at_dot.spamfree.com>:
> It can get almost metaphysical, but:
> Identifying a column which has an undeterminable value ( NULL) is not
> the same as identifying that value, so being able to
> consider that column unique ( that is , it is the only one with the
> undeterminable value) is not a problem.
>
The difference you point to is clear for me.
But i did not find a real world example for
a column which is unique in a table and at
most one row with a NULL value for this column
should be allowed.
--
Frank Piron,
etfrankatkonaddotn
(leftrotate two)
Received on Fri Oct 22 2004 - 08:50:42 CDT
