Have you seen these errors?
NoMethodError: undefined method `columns_hash' for "":String
NoMethodError: undefined method `private_method_defined?' for "":String
If you’ve tried using Rails 3 with a legacy database, it is possible you’ve run across issues with some of your columns having the same name as existing methods of instances of ActiveRecord::Base. My primary example of this has been columns with the name ‘class’. If you can’t change the column name to be ‘klass’ or ‘clazz’, then you may want to consider my solution to this issue.
I’ve created a gem called safe_attributes that turns off the creation of the attribute accessors that conflict with existing instance methods of ActiveRecord::Base.