Ruby on Rails

Slashdot must be getting desperate. Yesterday they had a lengthy discussion on the Future of Emacs, and today they had yet another discussion as to whether Java is so 90s. Meanwhile, tonight at the SDForum Emerging Tech SIG, we heard Tom Hill (founder of the SDForum Java SIG) talk about Ruby on Rails, the hottest new software technology on the block.

Ruby is another of those object oriented scripting language that is apparently typeless but seems to always do what is expected without overspecification. Rails is a web application framework written in Ruby that is also designed to do just the right thing. Together they make a terrific base for web based applications. All you need is Ruby on Rails, a database, a web server and a little development time and you are in business.

Tom touched on many interesting topics during his presentation. The one that struck me is the treatment of persistence in Ruby compared to say Hibernate. Hibernate is a Java framework that I mentioned in my last post for persisting Java objects in a database. With Hibernate you specify the object in Java and also specify the database schema and Hibernate does the mapping and transference between these two representations.

In Ruby, the ActiveRecord component gets the object specification from the database schema and creates an object based on the database record structure. There is only one specification of the object structure, so there is no problem with synchronization of specifications. Moreover, the Ruby object automatically adjusts to changes in the database schema without necessarily needing changes to the program.

In practice, a database needs its schema otherwise it would not know how to access and deliver its data. In this light, having the application language bend to use the database schema for its object structure seems sensible, and Ruby makes it seamless.