Re: Strange behaviour on function

From: Adrian Klaver <adrian(dot)klaver(at)aklaver(dot)com>
To: Lorusso Domenico <domenico(dot)l76(at)gmail(dot)com>, pgsql-general(at)lists(dot)postgresql(dot)org
Subject: Re: Strange behaviour on function
Date: 2023-07-05 15:16:26
Message-ID: 84a4f250-e12f-9dd8-bf97-c794f6b909f5@aklaver.com
Views: Raw Message | Whole Thread | Download mbox | Resend email
Thread:
Lists: pgsql-general

On 7/5/23 05:23, Lorusso Domenico wrote:
> Hello guys,
> here a simple function
>
> CREATE OR REPLACE FUNCTION bind_action(
> sqlstr text,
> hrec hstore)
>     RETURNS text
>     LANGUAGE 'plpgsql'
>     COST 100
>     immutable PARALLEL SAFE
> AS $BODY$
> declare
> _sqlstr text=sqlstr;
> _k text;
> _debug text;
> begin
> _debug= '--Start' || _sqlstr;
> foreach _k in array akeys(hrec) loop
> _debug =_debug || format($$
> hstore: %s %s
> sqlStr:$$, _k,  hrec[_k]);
> _sqlstr=replace(_sqlstr, ':'||_k||':', hrec[_k]);
> _debug =_debug ||  _sqlstr;
>
> end loop;
>
> raise notice 'final %',_debug;
> return _sqlstr;
> end;
> $BODY$;
>
> and here a simple test
> do
> $$
> declare
> sqlstr text=':id::bignt,:surpa:,:disfa:';
> hs hstore;
> begin
> hs['id']=789;
> hs['disfa']='ssssssss';
> raise notice '%',bind_action(sqlstr,hs);
> end;
> $$;
>
> and it works.
> But...
> When I call this function in a function called by a trigger it down't work
> _debug variable becomes null, also _sqlstr becomes null...

https://www.postgresql.org/docs/current/plpgsql-trigger.html

1)
"A trigger function must return either NULL or a record/row value having
exactly the structure of the table the trigger was fired for."

2) I am not seeing where you use:

"TG_ARGV[]

Data type array of text; the arguments from the CREATE TRIGGER
statement. The index counts from 0. Invalid indexes (less than 0 or
greater than or equal to tg_nargs) result in a null value."

So I don't see how sqlstr is being set?

>
> I can't identify what is going to happens...
>
> any idea?
>
>
> thanks
>
> --
> Domenico L.
>
> per stupire mezz'ora basta un libro di storia,
> io cercai di imparare la Treccani a memoria... [F.d.A.]

--
Adrian Klaver
adrian(dot)klaver(at)aklaver(dot)com

In response to

Responses

Browse pgsql-general by date

  From Date Subject
Next Message Erik Wienhold 2023-07-05 15:33:44 Re: Strange behaviour on function
Previous Message Erik Wienhold 2023-07-05 13:53:11 Re: Strange behaviour on function