From: | Daniele Varrazzo <daniele(dot)varrazzo(at)gmail(dot)com> |
---|---|
To: | Karsten Hilbert <Karsten(dot)Hilbert(at)gmx(dot)net> |
Cc: | psycopg(at)postgresql(dot)org |
Subject: | Re: Range type adaptation implemented |
Date: | 2012-09-24 09:57:53 |
Message-ID: | CA+mi_8b1dr5S0BM0KidDVX7j0_Seh5CGLs4vNiu40VEj3=MQ7g@mail.gmail.com |
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Lists: | psycopg |
On Mon, Sep 24, 2012 at 10:45 AM, Karsten Hilbert
<Karsten(dot)Hilbert(at)gmx(dot)net> wrote:
> On Mon, Sep 24, 2012 at 09:56:14AM +0100, Daniele Varrazzo wrote:
>
>> The funniest surprise I've had during the development
>> was an error creating the object TextRange('#', '$') in the database.
>> It should be possible as
>>
>> >>> ord('#'), ord('$')
>> (35, 36)
>>
>> but PG insisted that "range lower bound must be less than or equal to
>> range upper bound". Well, turns out that:
>>
>> postgres=# select ascii('#') < ascii('$'), '#' < '$';
>> ?column? | ?column?
>> ----------+----------
>> t | f
>> (1 row)
>
> This does not seem intuitive but is probably quite logical:
>
> While
>
> ascii('#') < ascii('$')
>
> eventually compares numerical values (35 and 36) the comparison
>
> '#' < '$'
>
> operates on characters the sorting order (<) of which
> depends on the lcoale in use.
That's right: the reason is the locale. select '#' collate "C" < '$'
collate "C" returns true as naively expected.
-- Daniele
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