Why is this render :partial line iterating my collection twice? - ruby-on-rails

Question

Given these relationships:
class Account < ActiveRecord::Base
has_many :employments
has_many :people, :through => :employments
accepts_nested_attributes_for :employments
end
class Employment < ActiveRecord::Base
belongs_to :account
belongs_To :person
end
I'm trying to list the employment records for an account:
<% form_for #account do |f| -%>
<% f.fields_for :employments do |e| -%>
<%= render :partial => 'employment', :collection => #account.employments, :locals => { :f => e } %>
<% end -%>
<% end -%>
I've verified that the employment table in #account contains two records, but I get four copies of the partial because it iterates employments twice:
Employment Load (1.0ms) SELECT * FROM [employments] WHERE ([employments].account_id = 1)
Person Load (1.3ms) SELECT * FROM [people] WHERE ([people].[id] = 2)
Rendered accounts/_employment (17.9ms)
Person Load (1.5ms) SELECT * FROM [people] WHERE ([people].[id] = 1)
Rendered accounts/_employment (5.1ms)
Rendered accounts/_employment (2.2ms)
Rendered accounts/_employment (2.1ms)
Can anybody explain why that would happen?
Here's some additional information:
The _employment.html.erb partial:
<div class="employment">
<span class="name"><%= link_to h(employment.person.name), person_path(employment.person) %></span>
<span class="role"><%=h employment.role %></span>
<span class="commands"><%= remove_child_link "Remove", f %></span>
</div>
remove_child_link is the only place I need to generate a form field at. It creates the _delete field for the record and wires up a remove link that changes the value to '1'. The 'role' property may also be editable, though. The important thing is I don't want all of the fields to be editable.
The accounts_controller actions for this view:
def edit
#account = Account.find(params[:id])
end
def update
#account = Account.find(params[:id])
respond_to do |format|
if #account.update_attributes(params[:account])
flash[:notice] = "#{#account.business_name} was successfully updated."
format.html { redirect_to #account }
else
format.html { render :action => "edit" }
end
end
end
Ben got me going in the right direction. Some runtime inspection reveals that the record is stored in the object variable (which I already knew, but in a different context). So I can rewrite the fields_for clause as:
<% form_for #account do |f| -%>
<% f.fields_for :employments do |e| -%>
<div class="employment">
<span class="name"><%= link_to h(e.object.person.name), person_path(e.object.person) %></span>
<span class="role"><%=h e.object.role %></span>
<span class="commands"><%= remove_child_link "Remove", e %></span>
</div>
<% end -%>
<% end -%>

Answer 1

Its rendering that partial for each field in the employments model - when really you want to do it once for each employment record. That is, remove the iteration over the fields_for:
<% form_for #account do |f| -%>
<%= render :partial => 'employment', :collection => #account.employments %>
<% end -%>

Answer 2

You are correct to use fields_for, but it will render what's inside of it for each employment, so remove the :collection parameter from render :partial. Instead, use nested forms by putting this in your Account model:
accepts_nested_attributes_for :employments
read more about nested forms here: http://ryandaigle.com/articles/2009/2/1/what-s-new-in-edge-rails-nested-attributes