From: Michael Neumann <uu9r@...>
Date: 2002-09-06T20:16:55+09:00
Subject: Re: dbi question

Jacques wrote:
> Hello, I was wondering if there is an elegant way of seeing if a query
> is empty in ruby-dbi. Thank you for your time.

There are two solutions, both of which are not very elegant:

- Use COUNT(*) in your SQL statement, to see how many rows are in the
  result. Then use select_one to get this number.

- Call method fetch once. If it returns nil, the query was empty. 


If you're using the Postgres DBD, use:

  sth = dbh.execute(query)
  sth['pg_row_count']    # returns the number of rows in the result


Try method StatementHandle#rows, if it returns the number of rows in the
result set. But pay attention that if that's the case, it's not the correct 
behaviour of that DBD.

Regards,

  Michael