Rails - Jan 2006 - ActiveRecord, << or push_with_attributes: update if exists?

In the Agile Rails book, on page 232 (PDF, 4th edition) there is an 
example of (within ActiveRecord) marking an article as read by a user at 
the present time. Short example code (from the book) here:

	class User < ActiveRecord::Base
	  has_and_belongs_to_many :articles

	  def read_article(article)
	    articles.push_with_attributes(article, :read_at => Time.now)
	  end

	  # ...
	end

However, it seems this piece of code would only work the first time you 
read a specific article. It appears to always create a new join table 
post, and not to just update if there is an existing post. How would one 
best solve this?


-- 
Posted via http://www.ruby-forum.com/.

Henrik wrote:
> 	class User < ActiveRecord::Base
> 	  has_and_belongs_to_many :articles
> 
> 	  def read_article(article)
> 	    articles.push_with_attributes(article, :read_at => Time.now)
> 	  end
> 
> However, it seems this piece of code would only work the first time you 
> read a specific article. It appears to always create a new join table 
> post, and not to just update if there is an existing post. How would one 
> best solve this?
Here is an update_attributes method for has_and_belongs_to_many associations:

http://encytemedia.com/blog/articles/2005/06/15/storing-additional-data-on-join-tables-with-rails#comment-490

However: (1) I would have thought this goes in a file in lib rather than
              in application_helper.rb,
          (2) The "end" on the first line shouldn''t be there,
and
          (3) "> 0" could be added to the end of the DB call so
that a
               boolean is returned like the usual update_attributes method.

Are there any other solutions out there?  Should something like this be
added to the ActiveRecord distribution?

-- 
We develop, watch us RoR, in numbers too big to ignore.