Re: type cast/validation functions

On Tue, Dec 28, 2004 at 09:50:09PM +0000, Robert Wimmer wrote:
> 
> as i posted a few weeks ago, it is a handicap for me writing client side 
> appliciations with postgres, that you cant catch errorcodes - especially 
> after type casts. so you have to rewrite type check functions for every 
> client system.

Would 8.0's subtransactions, in particular PL/pgSQL's new error
trapping construct, solve your problem?

CREATE OR REPLACE FUNCTION text2date(TEXT) RETURNS DATE AS $$
DECLARE   dat  DATE;
BEGIN   BEGIN       dat := CAST($1 AS DATE);   EXCEPTION       WHEN invalid_datetime_format OR datetime_field_overflow
THEN          RAISE INFO 'Bogus date ''%'', returning NULL', $1;           dat := NULL;   END;
 
   RETURN dat;
END;
$$ LANGUAGE plpgsql IMMUTABLE STRICT;

> if someone is interested in my solution there is a demo and a short 
> description available at
> 
> http://www.wiro.co.at/postgres/test/demo_en.php

This link returns 404 Not Found -- the correct link appears to be:

http://www.wiro.co.at/postgres/demo_en.php

-- 
Michael Fuhr
http://www.fuhr.org/~mfuhr/