Re: pgsql: doc: add examples of creative use of unique expressionindexes

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От Bruce Momjian
Тема Re: pgsql: doc: add examples of creative use of unique expressionindexes
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Msg-id 20200411001709.GD24988@momjian.us
обсуждение исходный текст
Ответ на Re: pgsql: doc: add examples of creative use of unique expression indexes  (Tom Lane <tgl@sss.pgh.pa.us>)
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On Fri, Apr 10, 2020 at 07:21:29PM -0400, Tom Lane wrote:
> Bruce Momjian <bruce@momjian.us> writes:
> > I agree with your analysis.  I still want to have some mention that
> > partial indexes can be used to create single-NULL columns, which might
> > be required for compatibility with other databases.  Attached is an
> > updated patch which removes the previous commit but adds a mention of
> > this.
> 
> The single-null thing is probably a useful example, but please make
> it an actual separate example, or at least its own para outside the
> existing <example> sections.
> 
> Also, the existing example demonstrating that seems overcomplicated;
> why not just
> 
>     create unique index ... (1) where (foo is null);

I ended up using "true" since that is ony one byte;  patch attached.

-- 
  Bruce Momjian  <bruce@momjian.us>        https://momjian.us
  EnterpriseDB                             https://enterprisedb.com

+ As you are, so once was I.  As I am, so you will be. +
+                      Ancient Roman grave inscription +

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