public inbox for [email protected]
help / color / mirror / Atom feedFrom: Jack Douglas <[email protected]>
To: Josh Kupershmidt <[email protected]>
Cc: [email protected]
Subject: Re: boolean states
Date: Fri, 29 Apr 2011 08:29:45 +0100
Message-ID: <[email protected]> (raw)
In-Reply-To: <[email protected]>
References: <[email protected]>
<[email protected]>
> I'd vote for just ripping out the:
> | A third state, "unknown", is represented by the SQL null value.
>
> sentence entirely. I see no reason why NULL should be talked about in
> particular on the page about boolean data types; there are many data
> types, any of which might be NULL.
NULL is not unique to boolean, but UNKNOWN is - it would surely be wrong
to have no mention of it at all on this page. This is because the
boolean type is the only one used to represent truth (or logical)
values. One of the comments from the link you provided:
> What’s even more interesting is that for BOOLEAN they invented the
> keyword UNKNOWN and the 2003 standard states “The null value of the
> boolean data type is equivalent to the Unknown truth value.” So for
> BOOLEAN (and only BOOLEAN AFAICT) you’re supposed to say WHERE
> <boolean primary> IS [NOT] UNKNOWN. And in the definition of
> “literal”, which is supposed to “Specify a non-null value”, “boolean
> literal” is equated to TRUE, FALSE or UNKNOWN (but the latter is
> equivalent to a “null value” a few pages later).
view thread (10+ messages) latest in thread
reply
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Reply to all the recipients using the --to and --cc options:
reply via email
To: [email protected]
Cc: [email protected], [email protected]
Subject: Re: boolean states
In-Reply-To: <[email protected]>
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
This inbox is served by agora; see mirroring instructions
for how to clone and mirror all data and code used for this inbox