search for: actsasversioned

I have this situation where in an after_update, I would like to know the previous value of the record instead of simply being notified the record has been updated. For example let''s say I had a table called ''foo'' which had a field ''new_flag''. I want to know when the ''new_flag'' field changes from 0 -- > 1 in an after_update so I

Is there a ''replace'' method or similar for attchment_fu? For instance, I have an image that is uploaded and stored. Now I want to replace it with a different image. I do not want to do a delete and then new - since I need to keep various attributes associated with the previous image. thanks. --~--~---------~--~----~------------~-------~--~----~ You received this message

I need to implement multiple undo functionality into a Rails app (my first one). Essentially, every .update and .save needs to record the previous data set and save them in a history table along with some identifying stamps, so each db action can be rolled back at any time. From what i can tell, i could implement this manually using observers perhaps; but this is Rails, so i wonder if

I''ve been searching around trying to find out if there is some way to attach something to an ActiveRecord class such that every time an update is called, a record of that update (which fields, when) is created. I think it would be useful for syncing information with external services I think. Questions: If there is a wealth of knowledge on this, what search terms will lead me in the