ActiveRecord is my favorite way to access a SQL database. It offers very useful validation inside of a model. But sometimes you just want to save an attribute quickly, without validating the whole object. For that you can pass a parameter to the save method.
object.save(:validate => false)
That saved me a lot of time. Awesome!
Robert Reiz 
This works fine for validations, but it doesn’t have any effect to “before” filters like “before_save”. I think that is a very important note! 🙂