Forms for nested objects in Rails

I am having trouble creating a form to edit StudentReferrals. Each Student has some basic information like name/birthday/studentid. In addition to that information, students are referred to take a list of classes. I want to have a form that allows someone to fill out the student info, and then select up to 10 classes that the student is required to take. In addition to the classes, each "Student+Course" combo has a credits_required field that says how many credits of a class that student is required to take.

The list of classes that a student can take comes from the Course model

I have 3 models:

class StudentReferral < ActiveRecord::Base
  has_many :student_referral_courses, :dependent => :destroy
  has_many :courses, :through => :student_referral_courses

  # Fields: name, studentid, advisor_name, birthday
end

class StudentReferralCourse < ActiveRecord::Base
  belongs_to  :student_referral
  belongs_to  :course

  validates_presence_of :credits_required

  # Fields: (student_referral_id, course_id, credits_required)

  attr_accessor :course1, ..., :course9
  attr_accessor :credits1, ..., :credits9

  after_create  :add_courses

  def add_courses

    self.student_referral_courses.destroy_all

    unless self.course1.blank?
      self.student_referral_courses.create! :course_id => self.course1, :student_referral_id => self.id, :credits_required => self.credits1
    end
    unless self.course2.blank?
      self.student_referral_courses.create! :course_id => self.course2, :student_referral_id => self.id, :credits_required => self.credits2
    end
    ...
end

class Course < ActiveRecord::Base
  # Fields: department, name
end

And I have a form to created/edit the student referrals that is like the following:

<%= form_for(@student_referral) do |f| %>
  <% if @student_referral.errors.any? %>
    <div id="error_explanation">
      <h2><%= pluralize(@student_referral.errors.count, "error") %> prohibited this student referral from being saved:</h2>

      <ul>
      <% @student_referral.errors.full_messages.each do |msg| %>
        <li><%= msg %></li>
      <% end %>
      </ul>
    </div>
  <% end %>



<fieldset class="form">
<legend>Student Information</legend>
<table cellpadding="3" cellspacing="0" border="0" class="vert">
<tr><th class="subr"><%= f.label :studentid %></th><td><%= f.text_field :studentid %></td></tr>
<tr><th class="subr"><%= f.label :name %></th><td><%= f.text_field :name %></td></tr>
<tr><th class="subr"><%= f.label :birthday %></th><td><%= f.date_select :birthday, :start_year => 1990 %></td></tr>
<tr><th class="subr"><%= f.label :advisor %></th><td><%= f.text_field :advisor %></td></tr>
</table>
</fieldset>


<fieldset class="form">
<legend>Course Information</legend>
&开发者_如何转开发lt;span>You <b>MUST</b> select the credits required for each course.</span>
<ol>
<li><%= select(:student_referral, :course1, Course.all(:order => "dept,name ASC").collect {|p| [ "#{p.dept}: #{p.name}", p.id ] }, { :include_blank => '' })%>
    <%= select_tag 'student_referral[credits1]', options_for_select(['Select One',5.0,4.5,4.0,3.5,3.0,2.5,2.0,1.5,1.0,0.5]) %></li>
<li><%= select(:student_referral, :course2, Course.all(:order => "dept,name ASC").collect {|p| [ "#{p.dept}: #{p.name}", p.id ] }, { :include_blank => '' })%>
    <%= select_tag 'student_referral[credits2]', options_for_select(['Select One',5.0,4.5,4.0,3.5,3.0,2.5,2.0,1.5,1.0,0.5]) %></li>
    ...
</ol>
</fieldset>

<%= f.submit :class => "l-button black" %>

<% end %>

My problem is that I cannot seem to create or edit any of these records without doing a terrible hack using the validation. I have 10 attr_accessible fields for course1 to course9 and same for credits that I use on an after_create macro. However, this does not let me see any validation errors from the course (like if they do not put any credits)

I tried using accepts_nested_attributes_for :student_referral_courses but I can't seem to get it to do what I want. I really want to do this the Rails way and I feel like I am doing a terrible hack.

Try adding the has_many :through's to course i.e.

class Course < ActiveRecord::Base
has_many :student_referrals, :dependent => :destroy
has_many :student_referral_courses, :through => :student_referrals
end