Обсуждение: Re: [GENERAL] 'a' == 'a '

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Re: [GENERAL] 'a' == 'a '

От
"Dann Corbit"
Дата:
> -----Original Message-----
> From: Bruce Momjian [mailto:pgman@candle.pha.pa.us]
> Sent: Monday, October 24, 2005 5:57 PM
> To: Dann Corbit
> Cc: Tom Lane; Richard_D_Levine@raytheon.com; general@postgresql.org;
> pgsql-hackers@postgresql.org
> Subject: Re: [GENERAL] [HACKERS] 'a' == 'a '
>
> Dann Corbit wrote:
> > Document the collating sequences used for the character types.
>
> Sorry, I don't understand that.  What does it mean?

According to the standard, comparisons against character types are
supposed to PAD with either <space> or <PAD CHAR> according to the
collating sequence and not according to the data type.

Since the padding behavior of PosgreSQL comparisons for character types
is different according to the data type and not the collating sequence,
what is needed is simply to define the collating sequence used for
different character types.



Re: [GENERAL] 'a' == 'a '

От
Bruce Momjian
Дата:
Dann Corbit wrote:
> > -----Original Message-----
> > From: Bruce Momjian [mailto:pgman@candle.pha.pa.us]
> > Sent: Monday, October 24, 2005 5:57 PM
> > To: Dann Corbit
> > Cc: Tom Lane; Richard_D_Levine@raytheon.com; general@postgresql.org;
> > pgsql-hackers@postgresql.org
> > Subject: Re: [GENERAL] [HACKERS] 'a' == 'a '
> > 
> > Dann Corbit wrote:
> > > Document the collating sequences used for the character types.
> > 
> > Sorry, I don't understand that.  What does it mean?
> 
> According to the standard, comparisons against character types are
> supposed to PAD with either <space> or <PAD CHAR> according to the
> collating sequence and not according to the data type.
> 
> Since the padding behavior of PosgreSQL comparisons for character types
> is different according to the data type and not the collating sequence,
> what is needed is simply to define the collating sequence used for
> different character types.

But isn't collating sequence related to ordering?  How does this relate
to padding?

--  Bruce Momjian                        |  http://candle.pha.pa.us pgman@candle.pha.pa.us               |  (610)
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