how to read a variable upon insert?

I am running Postgres 6.3.2 and have a question.

I have a field, called "idnum", that automagically gets assigned a value
when something is inserted. I want to know that value when I do the
insert:

$sth = $dbh->prepare("INSERT INTO foo (bar) VALUES('$bar')");
$sth->execute;
$insertid = $sth->{'idnum'};

I would think that last line should be able to retreive it from the
statment handle, but it doesn't work.

Is the only way, to do *another* select after I insert and get the data?
I would hope after doing the insert, since I have the statment handle, I
could get the value.

Brian

-----------------------------------------------------
Brian Feeny (BF304) signal(at)shreve(dot)net
318-222-2638 x 109 http://www.shreve.net/~signal
Network Administrator ShreveNet Inc. (ASN 11881)