[Rails] [ANN] Rails 0.9.3: Optimistic locking, dynamic finders, Ruby 1.8.2 compatible

[David Heinemeier Hansson]

Rails is now fully compatible with Ruby 1.8.2, which we advice all to 
upgrade to as soon as possible. It contains a year's worth of bug fixes 
for Ruby, so it's great finally to be able to use the new version with 
Rails. But that is not all we got in store for 0.9.3. A few of the 
highlights are:

* Automated optimistic locking: Just add the field @lock_version@ to 
your table and the associated class will be governed by optimistic 
locking that'll raise an exception if a stale object attempts to save.

* Dynamic finders: Finders like Person.find_by_user_name, 
Payment.find_by_amount, and even Person.find_by_user_name_and_password 
are now available with no code at all. Any column can be used and 
combined with other columns in the new dynamic finders.

* MS SQL Server and DB2: Active Record now supports both Microsoft SQL 
Server (through ADO) and IBM's DB2 databases.

* MemCacheStore for sessions: You can now store sessions in Action Pack 
using Danga's memcache technology.

* Generators guard against reserved words:* Not only will 
./script/generate model Thread be denied, you'll also get a list of 
synonyms pulled live from WordNet!

That's just a small taste of the 35 changes, fixes, and features 
introduced with Rails 0.9.3. You can read the full story in the 
changelogs:

* Active Record: http://ar.rubyonrails.com/files/CHANGELOG.html
* Action Pack  : http://ap.rubyonrails.com/files/CHANGELOG.html
* Rails        : http://rails.rubyonrails.com/files/CHANGELOG.html


The new web presence
====================

Since the last release, we've also launched a brand new website and 
visual identity for Rails. This includes the long awaited logo by John 
Hicks with a remix by Olivier Hericord. Check it all out at: 
http://www.rubyonrails.org


Upgrading from Rails 0.9.2 to 0.9.3
===================================

There's only one change you need to make in order to have your 
application updated from 0.9.2 to 0.9.3. In the 
config/environments/production.rb and config/environments/test.rb, you 
need to change:

   ActionController::Base.reload_dependencies = false
   ActiveRecord::Base.reload_associations     = false

...to:

   Dependencies.mechanism = :require<

And in config/environments/development.rb, you need to change:

   ActionController::Base.reload_dependencies = true
   ActiveRecord::Base.reload_associations     = true

...to:

   Dependencies.mechanism = :load

If you're coming on from 0.8.x, you'll need to go through the <a 
href="http://manuals.rubyonrails.com/read/book/3">Upgrading to 0.9 
manual</a>.
--
David Heinemeier Hansson,
http://www.basecamphq.com/   -- Web-based Project Management
http://www.rubyonrails.org/  -- Web-application framework for Ruby
http://macromates.com/       -- TextMate: Code and markup editor (OS X)
http://www.loudthinking.com/ -- Broadcasting Brain