From: "Daniel P. Zepeda" <daniel@...>
Date: 2002-04-19T00:53:52+09:00
Subject: Re: ruby/postgres problem


On Fri, 19 Apr 2002 00:27:07 +0900
"Steve Cranford" <stevecranford@cox.net> wrote:

> I'm trying to determine if a resultset is empty.  if it is, I want to
> perform other actions.  I tried this code and it didn't work:
> 
> result=conn.exec(sql)
> msg="testing"
> 
> if result.num_tuples==0
>     # run an insert
>     msg="new action"
> end
> 
> msg<< result.num_tuples.to_s #or a variation, I see the number.
> 
> the number of tuples correctly reports on the screen but the if block
> never executes.  I've had similar problems with numeric values in a case
> statement.  I've tried using variables in place of the values in the if
> statement as well as a (!result), but nothing seems to work.  what am I
> doing wrong?
> 
Try more whitespace in the predicate:

if result.num_tuples == 0 then 

I know it is not supposed to matter, and I may be mistaken, but I've got
the impression from experience that sometimes the whitespace does matter. 

This may be way off base, but it is something to try.

-- 
Daniel P. Zepeda
daniel@zepeda-zone.net