Chapter 1. Zero to Sixty: Introducing Rails

Rails may just be the most important open source project to be introduced in the past 10 years. It's promoted as one of the most productive web development frameworks of all time and is based on the increasingly important Ruby programming language. What has happened so far?

• By December 2006, you're likely to see more published books on Rails than any of Java's single flagship frameworks, including JSF, Spring, or Hibernate.

• The Rails framework has been downloaded at least 500,000 times in only its second year, as of May 2006. These statistics compare favorably with the most popular open source frameworks in any language.^[*]

  ^[*] The number 500,000 is actually a conservative estimate. Download statistics for a popular delivery vehicle, called gems, make it easy to track the number of Rails distributions by gems, but many other distributions exist, such as the Locomotive distribution on Mac OS X. The real download statistics could easily be twice this number.

• The Rails community mailing lists get hundreds of notes a day, compared to dozens on the most popular web development frameworks in other languages.

• The Rails framework has caused an explosion in the use of the Ruby programming language, which has been relatively obscure until recently.

• The Rails buzz generates increasingly hot debates on portals that focus on other programming languages. The Java community in particular has fiercely debated the Rails platform.

You don't have to go far to find great overviews of Rails. You can watch several educational videos that show Rails in action, narrated by the founder David Heinemeier Hansson. You can watch him build simple working applications, complete with a backing database and validation, in less than 10 minutes. But unlike the many quick-and-dirty environments you've seen, Rails lets you keep the quick and leave the dirty behind. It lets you build clean applications based on the model-view-controller philosophy. Rails is a special framework.

Sure, Rails has its limitations. Ruby has poor support for object-relational mapping (ORM) for legacy schemas; the Rails approach is less powerful than Java's approach, for example.^[*] Ruby does not yet have flagship integrated development environments. Every framework has limitations, and Rails is no different. But for a wide range of applications, the strengths of Rails far outpace its weaknesses.

^[*] For example, Hibernate supports three kinds of inheritance mapping, but Rails supports only single-table inheritance. Hibernate supports composite keys, but Rails is much more limited.