"Tom Dyess" <tdyess_at_dyessindustries.com> wrote in message
news:Sez38.422847$oj3.80035758_at_typhoon.tampabay.rr.com...
> > Pg. 203: "A listing of not NULL for the table column usually (although
> > not always) indicates that the table column is the primary key for
> > identifying unique rows in the table.
>
> Yes, once you start doing some heavy architecture, NOT NULLs are quite
> common for other columns than the primary key. I think this is a 'tip' for
> newbies.
I'm more than a little disappointed that this sort of thing creeps in. How
difficult is it to actually find out definitively the primary key constraint
for a table. Answer not at all. Why on earth give a 'tip' that is guaranteed
(100%) to give you the wrong answer sooner or later. Moreover you should IMO
always consider whether a table column should be NOT NULL, and or have a
default value and or be subject to a check constraint. This sort of
information is critical to good design.
--
Niall Litchfield
Oracle DBA
Audit Commission UK
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Received on Thu Jan 24 2002 - 03:12:39 CST
