Piku’s Blog

January 21, 2008

Rails with_scope tip

Filed under: Programming, Ruby on Rails — Tags: , , , — Mihai @ 10:03 pm

While searching some documentation about has_many :through I’ve found Josh Susser’s blog called (very imaginatively) “has_many :through” and the article about Magic join model creation in Rails Edge.

It is about using << on has_many through associations, before that you could use them only on habtm.

The article is quite old, 19 August 2006, and Rails has changed a bit since then, with_scope is now protected so now instead of

Contribution.with_scope(:create => join_attrs) { self << book }


Contribution.send(:with_scope, :create => join_attrs) { self << book }

For more information about many-to-many associations also see Many-to-many Dance-off in which habtm and has_many through is compared and Rails documentation.



  1. Trying to get this to work on Rails 3.0. I can throw up a testapp on Github for you to look at. Would love your help.

    Comment by Alexis M — December 5, 2010 @ 6:17 am

RSS feed for comments on this post. TrackBack URI

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

Create a free website or blog at WordPress.com.

%d bloggers like this: