From: Joel VanderWerf <vjoel@...>
Date: 2008-04-02T03:11:25+09:00
Subject: Re: should I use a database or a flat file?

James Dinkel wrote:
> I need to store some information with my ruby program and I am not sure
> on what would be the best method.  I'm mostly concerned about what would
> be the most efficient use of cpu resources.

One option is FSDB[1] (file-system database), with one file per 
"category", and each file stored as YAML. This scales as well as your 
file system scales, is always human-readable, and should be fairly 
efficient. (It's thread and process safe too, not that it matters for 
your app.)

For example:

   require 'fsdb'
   require 'yaml'

   db = FSDB::Database.new "~/tmp/my_data"
   db.formats = [FSDB::YAML_FORMAT] + db.formats

   3.times do |i|
     db["Cat#{i}.yml"] = %w{
       name1
       name2
       name3
     }
   end

   path = "Cat1.yml"

   puts "Here's the object:"
   puts "=================="
   p db[path]
   puts "=================="
   puts

   puts "Here's the file:"
   puts "=================="
   puts File.read(File.join(db.dir, path))
   puts "=================="
   puts

and this is the output:

Here's the object:
==================
["name1", "name2", "name3"]
==================

Here's the file:
==================
---
- name1
- name2
- name3
==================


The dir structure looks like this:

[~/tmp] ls my_data
Cat0.yml  Cat1.yml  Cat2.yml


[1] http://redshift.sourceforge.net/fsdb

-- 
       vjoel : Joel VanderWerf : path berkeley edu : 510 665 3407