Re: Per-column collation, proof of concept

On tor, 2010-07-15 at 05:57 +0200, Pavel Stehule wrote:
> :( maybe we have to enhance a locales - or do some work in this way.
> In Czech's IS is relative often operation some like
> 
> name = 'Stěhule' COLLATION cs_CZ_cs_ai -- compare case insensitive
> accent insensitive
> 
> PostgreSQL is last db, that doesn't integreated support for it

Well, the comparison function varstr_cmp() contains this comment:
   /*    * In some locales strcoll() can claim that nonidentical strings are    * equal.  Believing that would be bad
newsfor a number of reasons,    * so we follow Perl's lead and sort "equal" strings according to    * strcmp().    */
 

This might not be strictly necessary, seeing that citext obviously
doesn't work that way, but resolving this is really an orthogonal issue.
If you fix that and you have a locale that does what you want, my patch
will help you get your example working.