When to use association extensions vs named scopes?

Question

From a cursory glance, they appear to be simply two different approaches to the same set of problems, except that named scopes are chainable, while association extensions ar

Answer 1

Association extensions are very useful for creating custom methods for creating, updating, etc (not necessarily finding).

Because you have access to the proxy_owner, proxy_reflection, proxy_target, you have a nice hook into the relationship.

Check out the Association Extension section of the Rails docs:

http://api.rubyonrails.org/classes/ActiveRecord/Associations/ClassMethods.html

Answer 2

Yes, you are right, the main difference is that named_scope's are chainable. But they basically do the same function, its just that association extensions are faster.