[GENERAL] How return a row from a function so it is recognized as such by caller?

[Kenneth Tilton]

On version:

    PostgreSQL 9.1.2 on x86_64-unknown-linux-gnu, compiled by gcc (GCC)
4.4.5 20110214 (Red Hat 4.4.5-6), 64-bit

I get this error (all code at end of post) in pgAdmin:

NOTICE:  bpa inbound (,now_plus_30)
>
> CONTEXT:  SQL statement "select now_plus_30(NEW)"
>
> PL/pgSQL function "bp_alert_init" line 7 at SQL statement
>
> NOTICE:  warn time in input row = ("2012-04-27
>> 16:41:20.338239+00",now_plus_30)
>
> CONTEXT:  SQL statement "select now_plus_30(NEW)"
>
> PL/pgSQL function "bp_alert_init" line 7 at SQL statement
>
>
>>
>> ERROR:  invalid input syntax for type timestamp with time zone:
>> "("2012-04-27 16:41:20.338239+00",now_plus_30)"
>
> CONTEXT:  PL/pgSQL function "bp_alert_init" line 7 at SQL statement
>
>
>> ********** Error **********
>
>
>> ERROR: invalid input syntax for type timestamp with time zone:
>> "("2012-04-27 16:41:20.338239+00",now_plus_30)"
>
> SQL state: 22007
>
> Context: PL/pgSQL function "bp_alert_init" line 7 at SQL statement
>
>
>>
Note that I have eliminated the complexity of the callback and simply call
the desired initializer directly. FWIW, using the desired EXECUTE statement
produces exactly the same error.

If I declare the receiving variable to be a record, pgAdmin shows me this:

NOTICE:  bpa inbound (,now_plus_30)
>
> CONTEXT:  SQL statement "select now_plus_30(NEW)"
>
> PL/pgSQL function "bp_alert_init" line 7 at SQL statement
>
> NOTICE:  warn time in input row = ("2012-04-27
>> 16:46:22.62478+00",now_plus_30)
>
> CONTEXT:  SQL statement "select now_plus_30(NEW)"
>
> PL/pgSQL function "bp_alert_init" line 7 at SQL statement
>
> NOTICE:  caller got bpa ("(""2012-04-27 16:46:22.62478+00"",now_plus_30)")
>> <-----------------
>
>
>>
>> ERROR:  record "bpa" has no field "warn_time"
>
> CONTEXT:  SQL statement "SELECT bpa.warn_time"
>
> PL/pgSQL function "bp_alert_init" line 9 at RAISE
>
>
So it looks as if I have to "unwrap" or eval the return value (or change
the way I am returning it). But the callee is declared as returning a
bp_alert and returns a variable of type bp_alert, so I am not sure what
more I can do in the callee. The caller is selecting into a variable of
type bp_alert, so that too seems clear.

Hints welcome, code next.

ken

-- code starts here -------------------------------------------------------

set search_path to public;
drop table if exists bp_alert cascade;

CREATE TABLE bp_alert (
  warn_time          timestamp WITH TIME ZONE,
  warn_time_init     text
)

CREATE OR REPLACE FUNCTION now_plus_30(bpa bp_alert)
  RETURNS bp_alert AS
$BODY$

declare
begin
   raise notice 'bpa inbound %', bpa;
   bpa.warn_time = now() + interval '30 days';
   raise notice 'warn time in input row = %', bpa;
   return bpa;
end;
$BODY$
  LANGUAGE plpgsql VOLATILE;

CREATE OR REPLACE FUNCTION bp_alert_init()
  RETURNS trigger AS
$BODY$

declare
   bpa bp_alert; -- make this a record and the "warn time in caller" raise
fails on bpa not having warn_time
begin
   -- no difference: execute 'select ' || NEW.warn_time_init || '($1)'
using NEW into bpa;
   select now_plus_30(NEW) into bpa;
   raise notice 'caller got bpa %', bpa;
   raise notice 'warn time in caller now %', bpa.warn_time;
   return bpa;
end;
$BODY$
  LANGUAGE plpgsql VOLATILE;

drop trigger if exists bp_alert on bp_alert;

CREATE TRIGGER bp_alert
  BEFORE INSERT
  ON bp_alert
  FOR EACH ROW
  EXECUTE PROCEDURE bp_alert_init();

insert into bp_alert (warn_time_init) values ('now_plus_30');