accepts_nested_attributes_for not saving the child attribute to the database

Question

My accepts_nested_attributes_for only saves the parent and not the child (nested) attributes. This is many_to_many relationship between parent and child.

Problem: nothing happens and nothing is saved. But on the page, I get this message:

utf8: "\xE2\x9C\x93"
authenticity_token: 9Pjxt7e5RRgWVGafRyMoDqBSqmtj/R2zBSiVxGGxFOI=
parent: !map:ActiveSupport::HashWithIndifferentAccess 
name: "Test"
gender: Male
children_attributes: !map:ActiveSupport::HashWithIndifferentAccess 
"0": !map:ActiveSupport::HashWithIndifferentAccess 
  email: 1234@testing.com
commit: Submit

From the msg on my terminal log, I think it's because the children_attributes never got saved as it was assigned a "0"?. This is the terminal msg:

Started POST "/parents" for 127.0.0.1 at 2011-09-14 11:14:14 -0400
Processing by ParentsController#create as HTML
Parameters: {"utf8"=>"✓", "authenticity_token"=>"9Pjxt7e5RRgWVGafRyMoDqBSqmtj/R2zBSiVxGGxFOI=", "parent"=>{"name"=>"123", "gender"=>"Male", "children_attributes"=>{"0"=>{"email"=>"1234@testing.com"}}}, "commit"=>"Submit"}
SQL (0.1ms)  BEGIN
SQL (0.6ms)  SELECT 1 FROM `children` WHERE (LOWER(`children`.`email`) = LOWER('1234@testing.com')) LIMIT 1
SQL (0.2ms)  ROLLBACK

Controller-

def new
  @parent = Parent.new
  @parent.children.build
end

def create
  @parent = Parent.new(params[:parent])
  if @parent.save
    redirect_to root_path
  else
    render 'new'
  end
end

Parent model -

attr_accessible :children_attributes
has_many :children, :through => :parent_child_relationships

accepts_nested_attributes_for :children

Child model -

has_many :parents, :through => :parent_child_relationships
validates :email, :name, :presence => true  

Parent form view -

<%= form_for(@parent, new_parent_path) do |f| %>

<div>
  <%= f.label(:name) %></br>    
  <%= f.text_field(:name) %>
</div>  

<div>
  <%= f.label(:gender) %> <br/>
  <%= f.select(:gender, ['Male', 'Female']) %>
</div>

  <%= f.fields_for :children do |ff| %>

  <div>
    <%= ff.label(:email)%></br>
    <%= ff.text_field(:email)%>
  </div>

  <% end %>

  <%= submit_tag "Submit" %>
<% end %>

Any help would be greatly appreciated! Thank you!

Answer 1

Check if there are any unsuccessful validations for the children model

You can validate on create, using something like below

validates_uniqueness_of  :xxxx, :on => :create

Answer 2

Can you change your validations on child model to :

validates :name, :presence => true
validates :email, :presence => true, :email => true

And see if that fixes it for you?