ruby on rails 3 - access associated record in view (show page) -

i have following association setup:

class image < activerecord::base   belongs_to :imageable, polymorphic: true    attr_accessible :photo   has_attached_file :photo, :styles => { :small_blog => "250x250#", :large_blog => "680x224#", :thumb => "95x95#" } end  class post < activerecord::base   has_many :images, as: :imageable    accepts_nested_attributes_for :images   attr_accessible :comments, :title, :images_attributes end 

to access image post within index page, example, put code in block , loop through using each:

<% @posts.each |p| %>    <% p.images.each |i| %>     <%= image_tag(i.photo.url(:large_blog), :class => 'image') %>   <% end %> <% end %> 

so when comes accessing post in show view accessing 1 record thought access image so:

<%= image_tag(@post.image.photo.url(:large_blog), :class => 'image') %> 

but seems if can't error like: undefined method 'image'.

im not thinking basic here , hoping point me in right direction.

you have got has_many relation image in post model, can't access post.image you've got collection of images each post. in plain english:

you've got here:

a collection of post (@posts) iterate each method

<% @posts.each |p| %> 

now p means single post has collection of images

  <% p.images.each |i| %> 

and again, iterate on images , display every single image attached post

    <%= image_tag(i.photo.url(:large_blog), :class => 'image') %>   <% end %> <% end %> 

so can see every post may have several images , if have 1 image still array, can access @post.images.each or @post.images.first (or last) if want first one.

if want able @post.image should add post model:

class post < activerecord::base has_one :image, conditions: { primary: true} # if want specify main photo , of course if have  'primary' in image model (...) 

you can add additional conditions (as in code above) select newest photo, etc. can read more here