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Re: [SPAM]Re: Questions about 9.0 release note

Tom Lane <tgl@sss.pgh.pa.us>

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From: Tom Lane <tgl@sss.pgh.pa.us>
To: Bruce Momjian <bruce@momjian.us>
Cc: Takahiro Itagaki <itagaki.takahiro@oss.ntt.co.jp>, Robert Haas <robertmhaas@gmail.com>, "pgsql-hackers@postgresql.org" <pgsql-hackers@postgresql.org>
Date: 2010-04-05T14:35:19Z
Lists: pgsql-hackers 
Bruce Momjian <bruce@momjian.us> writes:
> Tom Lane wrote:
>> Bruce Momjian <bruce@momjian.us> writes:
>>> +     Exclusion constraints ensure that if any two rows are compared on
>>> +     the specified columns or expressions using the specified operators,
>>> +     at least one of these operator comparisons will be false. The syntax is:
>> 
>> Isn't that phrasing outright incorrect?  Consider nulls.

> Well, doesn't a comparison returning null really behave as false? 
> Should I reword it as "not true" or "false or null"?

Either one.

			regards, tom lane