# has\_many :through does it support collection\_singular\_ids ?

**URL:** <https://discuss.rubyonrails.org/t/has-many-through-does-it-support-collection-singular-ids/6117>\
**Category:** rubyonrails-talk\
**Created:** [December 20, 2006, 2:25pm UTC](https://discuss.rubyonrails.org/t/has-many-through-does-it-support-collection-singular-ids/6117 "2006-12-20T14:25:55Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![Christos\_Zisopoulos2](https://avatars.discourse-cdn.com/v4/letter/c/e9bcb4/32.png) [@Christos\_Zisopoulos2](https://discuss.rubyonrails.org/u/Christos_Zisopoulos2)\
**Post date:** [December 20, 2006, 2:25pm UTC](https://discuss.rubyonrails.org/t/has-many-through-does-it-support-collection-singular-ids/6117/1 "2006-12-20T14:25:55Z")

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Good evening list members,

I have the following model:

&nbsp;&nbsp;class Author \< ActiveRecord::Base &nbsp;&nbsp;&nbsp;&nbsp;has\_many :authorships &nbsp;&nbsp;&nbsp;&nbsp;has\_many :books, :through =\> : authorships &nbsp;&nbsp;end

Should I be able to do the following?

&nbsp;&nbsp;Author.find(:first).book\_ids = [1,2,3]

I ask, because it doesn't. The docs state that it should, but it doesn't specialise in the case of a :through

This works fine BTW:

&nbsp;&nbsp;Author.find(:first).authorship\_ids = [12,13]

Do I really need to find and add (\<\<) my associated join models for books one by one?

-christos