nil is not a symbol for form_for

Question

I'm writing a simple form for editing customer's attributes (with Rails 3.1 and Ruby 1.9.3). The controller code:

def edit
    cust_id = params[:cust_id]
    output_id = params[:output_id]
    @cust = CustOutput.find(:all, :conditions => {:cust_id => cust_id, :output_id => output_id })
    logger.info(@cust[0].cust_id)
end

In the view:

<h2> Editing customer <%=@cust[0].cust_id %> with output id <%=@cust[0].output_id %></h2>
<div>
<%= form_for @cust[0] do |cust| %>
    <%= render "shared/error_messages", :target => @cust[0] %>
    <div id='id' class='outerDiv'>
        <%= cust.text_field :cust_id, :size => 20 %>
    </div>
    <div id='email1' class='outerDiv'>
        <label for='email1'>Email Part1</label>
        <%= cust.text_field :email_part1, :size => 20 %>
    </div>
    <div id='email2' class='outerDiv'>
        <label for='email2'>Email Part 2</label>
        <%= cust.text_field :email_part2, :size => 20 %>
    </div>
    <div id='dt' class='outerDiv'>
        <label for='dt'>Delivery Type</label>
        <%= cust.text_field :delivery_type, :size => 20 %>
    </div>
    <%= cust.submit "Save" %>
    <span class="cancel"><%= link_to "Cancel", :action=>"load", :cust_name=>"#{@cust[0].cust_id}" %>
<% end %>
</div>

The error message I got from opening edit page (http://localhost:3000/edit?cust_id=2&output_id=6):

nil is not a symbol
Extracted source (around line #3):

1: <h2> Editing customer <%=@cust[0].cust_id %> with output id <%=@cust[0].output_id %></h2>
2: <div>
3: <%= form_for @cust[0] do |cust| %>
4:     <%= render "shared/error_messages", :target => @cust[0] %>
5:     <div id='id' class='outerDiv'>
6:        <%= cust.text_field :cust_id, :size => 20 %>

The first thing is to check whether @cust[0] passed in is a nil object. In rails console I checked (with the provided cust_id and output_id)

@cust = CustOutput.find(:all, :conditions => {:cust_id => 2, :output_id => 6 })
CustOutput Load (0.7ms)  SELECT "cust_outputs".* FROM "cust_outputs" WHERE "cust_outputs"."cust_id" = 22 AND "cust_outputs"."output_id" = 6
=> [#<custOutput cust_id: 2, output_id: 6, email_part1: "abc@company.com", email_part2: nil, delivery_type: "ftp">]

Also from the logger I put in controller, there's actually a valid and correct cust_id output in the log. So, why do I still get nil is not a symbol error message? I've checked on CustOutput model as well and all attr_accessible fields are present.

Answer 1

It's a old question, but I recently have the same problem when doing maintenance in a old project. This project uses a different column for ID, but the primary key was not specified in the model.

After added these line all works:

self.primary_key = 'uuid'

Project use Rails 3.1 and MySQL 5.

Answer 2

如果您只想为集合中的第一个客户呈现表单，那么使用@cust.first怎么@cust.first ？

Answer 3

Try to use: ( :first instead of :all )

@cust = CustOutput.find(:first, :conditions => {:cust_id => cust_id, :output_id => output_id })

And in your form_for remove all the [0] references