Maulana Ruby

The public beta of Simplicant was officially released few days ago. As a follow up to my previous post . Here is some details according to official press release.

Simplicant allows SMEs to move towards a more organized, cleaner job applications management system. simplicant is the first web 2.0 applicant tracking system and brings the spirit of web 2.0 into hiring. It is completely web-based (Software as a Service) and makes use of powerful web 2.0 concepts like tags, rankings, search and collaboration to make the hiring experience easier, smoother and quicker.

Here is link to official press release:

Simplicant Goes into Public Beta 

Tags: RubyLanguage, Ruby on rails, Web 2.0

BitNami JRubyStack makes JRuby on Rails setup simple. The stack comes bundled with JRuby, Rails, Tomcat, Glassfish Gem, Mysql and Subversion. You can run your Rails app either with Glassfish or make a war and deloy to tomcat. The whole package is distributed under Apache 2.0 License.

There has been few sites that use JRuby proving that JRuby does scale. Thoughtworks project management application mingle is powered by JRuby and Rails. Sun mediacast site is also now running on JRuby and Rails

Tags: jruby, Rails

Matz talks about new Ruby version. Ruby 1.9 beta was released on christmas day at 25 december 2007.
Matz presents about new ruby version at google conference. The new version was earlier known as Yet Another Ruby Virtual machine (YARV). The main feature of Ruby 1.9 is support for platform threads. The Tread class in earlier Ruby VM’s were green threads.

It has been almost an year since my first Ruby on Rails project was launced as private beta. The Simplicant is simplest web based applicant tracking system. Based on years of experience in hiring of medium and small companies, simplicant gives you headstart when you want hire applicants in your comapnies. This Applicant tracking system not only allows you to post jobs on job board and recieve resumes, but also allows you to ask questions before you interview the applicant. After interview simplicant allows you to communicate with applicants

Simplicant has been totally overhauled  for performance and scalability. The web based interface has features that are found in todays Web 2.0 applications.

The company behind Simplicant is confiz solutions which is known for developing many of todays major Web 2.0 apps. The new public beta for will be launched soon.

Borrowing ideas from smalltalk-80 Evan Phoenix (of EngineYard) has created a new Ruby VM. The VM is written in C with Ruby like syntax. Language known as Garnet (formerly known as Cuby). Most parts of VM are written in Ruby itself except GC , Core VM (opcodes) and Primitives which are written in Garnet.

The link to InfoQ article is:

http://www.infoq.com/news/2007/07/rubinius-interview-part-one

Also look at Ruby VM performance shootout here:

http://www.oreillynet.com/ruby/blog/2007/02/fascinating_ruby_implementatio.html

This is a common to have join between two tables based on condition. suppose we have table in database called comments and we can have comments on different thing like a video, profile or picture. So keeping DRY (Don’t repeat yourself) principle in mind while designing your database. You may want to have relationship between single comments table and videos or profiles table.

At database level you should have two fields in table one field (i.e. type) that identifies the type of comment whether it is a comment on video or it’s a comment on profile, and another field (i.e source_id) that contains id of the video or profile that comment was on.

In Ruby on Rails currently there are two ways to define this kind of association between your activerecord models:

Single Table Inheritance:

Here you ‘ll create a single table of comments and Comment AR class, there would be two additional classes ProfileComment and VideoComment inheriting from same Comment AR class. Instead of having association between Profile and Comment model there would be association between Profile and ProfileComment subclass. Same will be the case with Video model and VideoComment subclass.

If we take a look at comment table we ‘ll see that class name for each record will be automatically stored in type field. The reference to associated table would be in source_id field.


class Comment < ActiveRecord::Base
end
class VideoComment < Comment
belongs_to :video, :foreign_key => “source_id”
end
class ProfileComment < Comment
belongs_to :profile, :foreign_key => “source_id”
end

Polymorphic Association:

Since Rails 1.1 there is a simpler way to create this kind of relationship called polymorphic association. In case of polymorphic association you ‘ll have two fields called commentable_type and commentable_id, instead of type and source_id. The commentable_type field will store name of class which that instance relates to and commentable_id saves the reference to instance of that class. The relations will be created like this:


class Comment < ActiveRecord::Base
belongs_to :commentable, :polymorphic => true
end
class Video < ActiveRecord::Base
has_many :comments, :as => :commentable
end
class Profile < ActiveRecord::Base
has_many :comments, :as => :commentable
end


Pros and Cons:

• The STI approach offers more flexibilty by allowing you to have additional fields that only have value in case of one sub class. For access from other sub class can be disallowed be overridden accessors.
• The STI requires you to create a seperate class to implement a relation between two models, resulting in more classses. which is not case with polymorphic association
• The STI results in more code.It is confusing to some programmers to understand relation between STI classes
• The polymorphic association is very easy to implement.

The usual migrate command syntax of

rake migrate VERSION=x

throws a warning informing the user that the command is deprecated, the new command syntax is

 rake db:migrate 

look at other depreciations in rails 1.2 at

http://www.railtie.net/articles/2006/11/02/deprecations-in-rails-1-2