Re: NULLs: theoretical problems?

From: V.J. Kumar <vjkmail_at_gmail.com>
Date: Fri, 24 Aug 2007 16:35:35 +0200 (CEST)
Message-ID: <Xns99966BC2529C0vdghher@194.177.96.26>

Jon Heggland <jon.heggland_at_idi.ntnu.no> wrote in news:famjo6$i68$1_at_orkan.itea.ntnu.no:

> In other words, the DEF query is equivalent to
>
> SELECT * FROM t WHERE t.a IS NOT NULL AND (t.a = 5 OR TRUE)
>

My understanding was that the DEF as written was a shorthand:

e.g.
'def(x):((x or y) and x)' -> '((def(x) or y) and def(x))'

You may be right, but then why the formula was not written with an explicit 'and' ? E.g. def(x) AND (((x or y) and x). Does ':' stand for 'and' ? It's all very confusing ! Perhaps, the author can explain because as it stands the notation is ambiguous. Received on Fri Aug 24 2007 - 09:35:35 CDT