I am getting a ' undefined method error ' when saving a comment

[ank k.]

hi!! I am a newbie in ROR.

I have two models

Post
has_many :Comment


Comment
belongs_to :Post


the error displays when I try to save a comment related to certain post.
I get the following error
-----------------------------------------------------------------
undefined method `comment' for nil:NilClass
-----------------------------------------------------------------
my comment controllers

def new
@comment = Comment.new
render :layout => false
end

def create
@post = Post.find_by_id(params[:id])
@post_comment = @post.comment.create(params[:comment])
if @post_comment.save
redirect_to post_index_path
flash[:success] = "comment created!!"
end

Could someone please explain why am I getting this error..

Thanks in advance :)

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[Germano Teixeira]

You shold use

has_many :comments

instead of

has_many :comment

Then you can call 

@post.comments

Look this example:
http://guides.rubyonrails.org/association_basics.html#the-has-many-through-association

Take a look at accepts_nested_attributes to create your posts:
http://api.rubyonrails.org/classes/ActiveRecord/NestedAttributes/ClassMethods.html

2013/8/22 ank k. <li...@ruby-forum.com>

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[Colin Law]

On 22 August 2013 20:56, ank k. <li...@ruby-forum.com> wrote:
> hi!! I am a newbie in ROR.
>
> I have two models
>
> Post
> has_many :Comment

that should be
has_many :comments
note that it is plural and lower case
>
>
> Comment
> belongs_to :Post

belongs_to :post

>
>
> the error displays when I try to save a comment related to certain post.
> I get the following error
> -----------------------------------------------------------------
> undefined method `comment' for nil:NilClass
> -----------------------------------------------------------------
> my comment controllers
>
> def new
> @comment = Comment.new
> render :layout => false
> end
>
> def create
> @post = Post.find_by_id(params[:id])
> @post_comment = @post.comment.create(params[:comment])

You have not told us which line the error points to but I guess it is
the one above. If so then it is saying that @post is nil, so your
find_by_id did not find anything. You don't need to use find_by_id,
you can just use
@post = Post.find( params[:id] )
Perhaps there is not a Post object with the correct id. If you look
in log/development.log you will see the params you are passing which
may give you a clue.

I suggest, however, that as a beginner you work right through a good
tutorial such as railstutorial.org (which is free to use online).
That will show you the basics of rails.

Also see the Rails Guides.

Colin