“Touch” updated_at column in Rails 2.3.2

问题:

I have a process which iterates through a bunch of ActiveRecord models, does some processing, and saves the models again. Often though, the processing doesn't result in an changes to the attributes and so the updated_at column never changes (even though save is called).

I'd prefer not to disable partial updates (in general, they're useful). I'm guessing that my two options are to:

1. Add a separate timestamp column to the model (i.e., 'processed_at') and manage this myself, although this seems a bit wasteful/redundant.
2. Or somehow override the management of the updated_at attribute?

I've heard that Rails 3 will have a 'touch' method which would be exactly what I'm looking for.

Any ideas/options/opinions?

回答1:

Actually the touch method is already in Rails 2.3.x, so you can simply do:

model.touch

To update the updated_at column. Alternatively, to update some other column with the current date and time use:

model.touch(:column_name)

回答2:

Now that the 2.3.x line has come and gone, a more definitive answer is that touch didn't make it into ActiveRecord until 2.3.8. So, anyone using still using Rails 2.3.2 (as the OP was -- and as I currently am) will need to find another way to "touch" their records.