Re: Proposal: 6NF
Date: Thu, 05 Oct 2006 22:16:05 GMT
Message-ID: <FufVg.4131$Cq3.3594_at_tornado.ohiordc.rr.com>
David Cressey wrote:
> "David Cressey" <dcressey_at_verizon.net> wrote in message
> news:F4uTg.998$rH1.633_at_trndny05...
>
>>First, let's find out where we all agree, then work our way towards where >>there are different viewpoints. >> >>Here's a starter: A schema in DKNF will have no nullable columns. >>
>
> I got no answers to the first point, but I think we all agree.
(I guess my contribution was lost in the ether.)
>
> Here's the next point.
>
> An outer join between two relational tables will, in general, produce a
> table with nullable columns.
Wait a minute: what does OUTER JOIN have to do with relational theory? Sure, SQL offers an OUTER JOIN, but...
What's outer about a join?
"On" or "of," sure; but "between?" Seems strange.
- "relational tables"
Relations or tables: they're different. Pick one.
- join "between"
Very vague.
- "[A] table with nullable columns..."
...is not a relation.
> Note: Brian Selzer has carried this point further in another subthread.
Yes, he has. Received on Fri Oct 06 2006 - 00:16:05 CEST