Re: R: Re: R: Re: Weird EXECUTE ... USING behaviour

2010/1/14 Vincenzo Romano <vincenzo(dot)romano(at)notorand(dot)it>:
> 2010/1/14 Pavel Stehule <pavel(dot)stehule(at)gmail(dot)com>:
>> 2010/1/14 Vincenzo Romano <vincenzo(dot)romano(at)notorand(dot)it>:
>>> 2010/1/14 Adrian Klaver <adrian(dot)klaver(at)gmail(dot)com>:
>>>> On Wednesday 13 January 2010 10:19:57 pm Vincenzo Romano wrote:
> ...
>>> CREATE OR REPLACE FUNCTION f()
>>> RETURNS VOID
>>> LANGUAGE plpgsql
>>> AS $function$
>>> DECLARE
>>>  cmd TEXT;
>>> BEGIN
>>>  EXECUTE '
>>>    SELECT $l0$ALTER TABLE test ALTER COLUMN i SET DEFAULT $1 $l0$
>>>  ' INTO cmd USING 42;
>>>  RAISE INFO '%',cmd;
>>> END;
>>> $function$
>>>
>>> SELECT f();
>>> INFO:  ALTER TABLE test ALTER COLUMN i SET DEFAULT $1
>>>
>>> The command to be executed is DML (SELECT). The substitution doesn't take place.
>>
>> yes. You cannot call SELECT 'ALTER ...'
>
> SELECT 'ALTER ...' is to select a text string into a variable!
> You mean the parse will give a look into my constant string to see
> whether I'm trying to build a dynamic DDL command?
> This would be awesome!
>

sorry. This is too much complicate.

Why do you use SELECT?

just

EXECUTE 'ALTER ... SET DEFAULT ' || 42.

There is other argument against USING + DDL. ALTER clause has syntax:

ALTER TABLE x SET DEFAULT expr.

but with USING clause you can pass only a value

Pavel

> --
> Vincenzo Romano
> NotOrAnd Information Technologies
> NON QVIETIS MARIBVS NAVTA PERITVS
>