If you've been looking for a good overview on Rails, look no further. This three-part series will help you understand this popular framework. It is excerpted from chapter one of the book Beginning Rails: From Novice to Professional, written by Jeffery Allan Hardy, Cloves Carneiro Jr. and Hampton Catlin (Apress, 2008; ISBN: 1590596862).
Introducing the Rails Framework - Enter Rails (Page 3 of 4 )
Rails is a best-of-breed framework for building web applications. It’s complete, open source, and cross-platform. It provides a powerful database abstraction layer called Active Record, which works with all popular database systems. It ships with a sensible set of defaults and provides a well-proven, multilayer system for organizing program files and concerns.
Above all, Rails is opinionated software. It has a philosophy on the art of web development that it takes very seriously. Fortunately, this philosophy is centered around beauty and productivity. You’ll find that as you learn Rails, it actually makes writing web applications pleasurable.
Originally created by David Heinemeier Hansson, Rails first took shape in the form of a wiki-wiki application called Instiki. The first version of what is now the Rails framework was actually extracted from a real-world, working application: Basecamp, by 37signals. The Rails creators took away all the Basecamp-specific parts, and what remained was Rails.
Because it was extracted from a real application and not built as an ivory tower exercise, Rails is practical and free of needless features. Its goal as a framework is to solve 80% of the problems that occur in web development, assuming that the remaining 20% are the problems that are truly unique to the application’s domain. It might be surprising that as much as 80% of the code in an application is infrastructure, but it’s not as farfetched as it sounds. Consider all the work that’s involved in application construction, from directory structure and naming conventions, to the database abstraction layer and the maintenance of state.
You’ll see that Rails has specific ideas about directory structure, file naming, data structures, method arguments, and, well, nearly everything. When you write a Rails application, you’re expected to follow the conventions that have been laid out for you. Instead of focusing on the details of knitting the application together, you get to focus on the 20% that really matters.
Ruby-on-Rails 
Advantages of the Rails Framework
