Re: Multi-column distinctness. - Mailing list pgsql-hackers

From Tomas Vondra
Subject Re: Multi-column distinctness.
Date
Msg-id 55F3082C.8050009@2ndquadrant.com
Whole thread Raw
In response to Re: Multi-column distinctness.  (Kyotaro HORIGUCHI <horiguchi.kyotaro@lab.ntt.co.jp>)
Responses Re: Multi-column distinctness.
List pgsql-hackers
On 09/07/2015 05:25 AM, Kyotaro HORIGUCHI wrote:
> Hello,
>
>> but making the COLUMN
>> required is certainly much worse as it breaks many existing scripts. The
>> keyword inky breaks cases that manipulate "statistics" column.
>
> Ouch! It is simply by accident, or my lack of carefulness. I will
> come up with fixed syntax later..
>
>> If any of this is unacceptable, then we probably need to come up with a
>> different syntax.

I've been thinking about the syntax, and I think both options (making 
COLUMN required or making STATISTICS a reserved keyword) will break 
something no matter what we do, forcing the users to either always use 
ADD COLUMN or quote all the existing uses of "statistics" (as column 
names, for example).

Maybe the best solution is to abandon the ALTER TABLE approach entirely, 
and instead invent a new set of commands
  CREATE STATISTICS  DROP STATISTICS

(ALTER STATISTICS seems a bit excessive at this point).

Another thing is that perhaps we should add names for statistics, just 
like we do for constraints, for example. Otherwise the DROP STATISTICS 
handling is rather awkward - for example if the user creates stats twice 
by mistake, he's unable to drop just one of them.

regards

-- 
Tomas Vondra                   http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services



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