# Form\_for **URL:** \ **Category:** Rails\ **Created:** [August 14, 2010, 3:23pm UTC](https://www.ruby-forum.com/t/form-for/193272 "2010-08-14T15:23:54Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![swengineer](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/97f17d/32.png) [@swengineer](https://www.ruby-forum.com/u/swengineer)\ **Post date:** [August 14, 2010, 3:23pm UTC](https://www.ruby-forum.com/t/form-for/193272/1 "2010-08-14T15:23:54Z")
At the following: [Getting Started with Rails — Ruby on Rails Guides](http://edgeguides.rubyonrails.org/getting_started.html) Under: 7.4 Generating a Controller It mentions the following: \<%= form\_for([@post, @post.comments.build]) do |f| %\> Now, this is what I know: form\_for: used to generate a form. @post: the object form\_for is bound to. The part I didn’t get here is: @post.comments.build What does that part provide me with? Thanks. ---
**Author:** ![swengineer](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/97f17d/32.png) [@swengineer](https://www.ruby-forum.com/u/swengineer)\ **Post date:** [August 14, 2010, 4:23pm UTC](https://www.ruby-forum.com/t/form-for/193272/2 "2010-08-14T16:23:21Z")
On Aug 14, 2:23 pm, Abder-Rahman A. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > form\_for: used to generate a form. > @post: the object form\_for is bound to. > > The part I didn’t get here is: > > @post.comments.build > > What does that part provide me with? It’s a namespaced resource - it’s a form for a new comment belonging to @post Fred ---
**Author:** ![swengineer](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/97f17d/32.png) [@swengineer](https://www.ruby-forum.com/u/swengineer)\ **Post date:** [August 14, 2010, 4:34pm UTC](https://www.ruby-forum.com/t/form-for/193272/3 "2010-08-14T16:34:27Z")
Frederick C. wrote: > On Aug 14, 2:23�pm, Abder-Rahman A. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > > > form\_for: used to generate a form. > > @post: the object form\_for is bound to. > > > > The part I didn’t get here is: > > > > @post.comments.build > > > > What does that part provide me with? > > It’s a namespaced resource - it’s a form for a new comment belonging > to @post > > Fred Thanks Fred. What is “namespaced resource”? Thanks. ---
**Author:** ![swengineer](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/97f17d/32.png) [@swengineer](https://www.ruby-forum.com/u/swengineer)\ **Post date:** [August 14, 2010, 5:03pm UTC](https://www.ruby-forum.com/t/form-for/193272/4 "2010-08-14T17:03:00Z")
Thanks Colin. ---
**Author:** ![swengineer](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/97f17d/32.png) [@swengineer](https://www.ruby-forum.com/u/swengineer)\ **Post date:** [August 14, 2010, 4:59pm UTC](https://www.ruby-forum.com/t/form-for/193272/5 "2010-08-14T16:59:04Z")
On 14 August 2010 15:34, Abder-Rahman A. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > > It’s a namespaced resource - it’s a form for a new comment belonging > > to @post > > > > Fred > > Thanks Fred. > > What is “namespaced resource”? Have a look at the guide on routing, (at [http://edgeguides.rubyonrails.org/](http://edgeguides.rubyonrails.org/)) it explains the use of namespaces. Also google would have given you useful information here again. Colin ---
**Author:** ![swengineer](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/97f17d/32.png) [@swengineer](https://www.ruby-forum.com/u/swengineer)\ **Post date:** [August 19, 2010, 9:16pm UTC](https://www.ruby-forum.com/t/form-for/193272/6 "2010-08-19T21:16:00Z")
This is a method generated for you by rails as a result of the associtions declared in the Post and Comment models - in this case belongs\_to and has\_many. Comments belongs to a post, and a post can have many comments. Rails creates quite a number of theses methods in response to the association, and different associations (has\_one, has\_and\_belongs\_to\_many etc.) create different sets of methods - more details in the API docs: > **[ActiveRecord::Associations::ClassMethods](https://edgeapi.rubyonrails.org/classes/ActiveRecord/Associations/ClassMethods.html)** > > Active Record Associations Associations are a set of macro-like class methods for tying objects together through foreign keys. collection.build is one of these methods, and the API docs explain it pretty well: “collection.build(attributes = {}, …) Returns one or more new objects of the collection type that have been instantiated with attributes and linked to this object through a foreign key, but have not yet been saved.” “collection” in this case is @post.comments (None of of which has anything to do with namespaced resources…) Matt.