How can I override the attribute assignment in an active record object?

Question

I know you can do this with virtual attributes, but what if the column actually exists?

For example, my model has a raw_topic column. When raw_topic is set, I want artist and song_title to be set based off of raw_topic's contents. Ideally, I'd like to override the raw_topic= method, but rails doesn't seem to like that.

What's the proper way of doing this? Is a callback the only way?

I've done similar things in the past, what do mean by "rails doesn't seem to like that", did you get an error when you tried it? — Corey

Ryan Bigg Ryan Bigg · Accepted Answer · 2010-03-27T07:22:05

You can do it like this:

def raw_topic=(value)
  # do something with raw topic
  self[:raw_topic] = value
end

That way you can ensure you still have the raw topic if you need to act on it.

How can I override the attribute assignment in an active record object?

1 Answers