Re: proposal: schema variables

pá 28. 2. 2020 v 16:30 odesílatel Pavel Stehule <pavel(dot)stehule(at)gmail(dot)com>
napsal:

>
>
> čt 27. 2. 2020 v 15:37 odesílatel Pavel Stehule <pavel(dot)stehule(at)gmail(dot)com>
> napsal:
>
>>
>> Hi
>>
>>
>>> 3) Any way to define CONSTANTs ?
>>> We already talked a bit about this subject and also Gilles Darold
>>> introduces it in this mailing-list topic but I'd like to insist on it.
>>> I think it would be nice to have a way to say that a variable should not
>>> be changed once defined.
>>> Maybe it's hard to implement and can be implemented later, but I just
>>> want to know if this concern is open.
>>>
>>
>> I played little bit with it and I didn't find any nice solution, but
>> maybe I found the solution. I had ideas about some variants, but almost all
>> time I had a problem with parser's shifts because all potential keywords
>> are not reserved.
>>
>> last variant, but maybe best is using keyword WITH
>>
>> So the syntax can looks like
>>
>> CREATE [ TEMP ] VARIABLE varname [ AS ] type [ NOT NULL ] [ DEFAULT
>> expression ] [ WITH [ OPTIONS ] '(' ... ')' ] ]
>>
>> What do you think about this syntax? It doesn't need any new keyword, and
>> it easy to enhance it.
>>
>> CREATE VARIABLE foo AS int DEFAULT 10 WITH OPTIONS ( CONSTANT);
>>
>
> After some more thinking and because in other patch I support syntax
> CREATE TRANSACTION VARIABLE ... I change my opinion and implemented support
> for
> syntax CREATE IMMUTABLE VARIABLE for define constants.
>

second try to fix pg_dump

Regards

Pavel

>
> See attached patch
>
> Regards
>
> Pavel
>
>
>>
>> ?
>>
>> Regards
>>
>> Pavel
>>
>>
>>