From: Adam Boyle <briefcase.speakers@...>
Date: 2007-11-01T23:06:51+09:00
Subject: Re: Extending ActiveRecord for csv export... a better way?

Daniel Sheppard wrote:
> require 'fastercsv'
> 
> def to_csv(records, filename=nil, columns=nil)
>   filename ||= "#{records.first.class.table_name}.dat"
>   columns ||= records.first.class.columns.map {|x| x.name }
>   FasterCSV.open(filename, 'w') do |csv|
>     records.each do |record|
>       csv << columns.map {|column| record.attributes[column] }
>     end
>   end
> end

Daniel, thank you for your reply and effort.  I tried this function out 
with no avail.  For some reason the output file is always empty (I have 
confirmed the table is not empty).  The file has the right number of 
lines, but no data.  I have come to the same end with this code:

#within the class inheriting ActiveRecord::Base
    def self.export_table_to_csv(delimiter = ",", options = nil)
      file = File.open("#{self.table_name}.dat", 
File::WRONLY|File::TRUNC|File::CREAT)
      rec = self.find(:all, options)
      for row in rec do
        line = columns.inject([]) { |arr, col| arr << row[col]; arr}
        file.puts(line.join("|"))
      end
    end

I am beginning to suspect that there is a problem with the columns logic 
in AR as related to the AR-JDBC extension (or perhaps specifically with 
the driver I'm using), but that is purely speculation on my part.  My 
Rubyism is not advanced enough to know how to debug that, but I'll look 
at the code for AR-JDBC and see if anything jumps out at me.

The link from yermej@gmail.com looks promising for setting up JRuby DBI 
with JDBC.  I'm going to try it out if I am unable to resolve this using 
AR-JDBC soon!

Thank you both for all your help!
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