From: "James Britt (rubydev)" <james@...>
Date: 2001-12-08T03:07:33+09:00
Subject: [ruby-talk:27829] Re: DBI and large result sets

Thanks to those who helped clarify things.

Just to be sure I really do understand, suppose I have some code making
a database connection to some remote machine.  I have an SQL query
I know will locate millions of rows.

Running 

   dbh.execute("SELECT * FROM MILLIONS_OF_EMPLOYEES") do |sth|
     sth.fetch do |row|
       p row
     end
   end

means the local code only has a single row in memory at any given time.

Using "fetch_all" in place of "fetch" means I have *all* of the rows in memory.
Using fetch_many(n) means I have n rows in memory at any given time. 


(My apologies if I'm either stating, or missing something, obvious.)

Thanks,

James