Rails Association Bug - ruby-on-rails

Question

I am getting NoMethodError in SitesController#index undefined method `name' for nil:NilClass in my Salesman index view and cannot find the culprit.
I have a simple rails app with the following tables: Customer, Salesman and Invoice.
In the index view for the customer table I have the following call:
<% #customers.each do |customer| %>
<%= customer.name %></td>
<%= customer.address %>
<%= customer.salesman.name %>
<% end %>
This is the call that results in the undefined method ´name´ listed above. I made sure the salesman table has a salesman_id foreign key in the customer table. Also, I made the respective association in the models:
class Customer < ActiveRecord::Base
belongs_to :salesman
has_many :invoices
end
class Salesman < ActiveRecord::Base
has_many :customers
end
I tested the customer.salesman.name call in the console and it works flawlessly. The show view for the customer has an exact call like this one and it also works. The only way I can make the customer index pass is by replacing customer.salesman.name to customer.salesman_id returning only the id.
Thank you for your time here.
***schema.rb***
ActiveRecord::Schema.define(version: 20150325172212) do
create_table "customers", force: :cascade do |t|
t.string "name"
t.string "address"
t.datetime "created_at", null: false
t.datetime "updated_at", null: false
t.integer "salesman_id"
end
create_table "invoices", force: :cascade do |t|
t.datetime "date"
t.string "fid"
t.integer "salesman_id"
t.datetime "created_at", null: false
t.datetime "updated_at", null: false
t.string "address"
end
create_table "salesmen", force: :cascade do |t|
t.datetime "name"
t.string "address""
t.datetime "created_at", null: false
t.datetime "updated_at", null: false
end
***controllers***
**customer**
Class CustomersController < ApplicationController
before_action :set_customer, only: [:show, :edit, :update, :destroy]
# GET /customers
# GET /customers.json
def index
#customers = Customer.all
end
# GET /customers/1
# GET /customers/1.json
def show
end
# GET /customers/new
def new
#customer = Customer.new
end
# GET /customers/1/edit
def edit
end
# POST /customers
# POST /customers.json
def create
#customer = Customer.new(customer_params)
respond_to do |format|
if #customer.save
format.html { redirect_to #customer, notice: 'Customer was successfully created.' }
format.json { render :show, status: :created, location: #customer }
else
format.html { render :new }
format.json { render json: #customer.errors, status: :unprocessable_entity }
end
end
end
# PATCH/PUT /customers/1
# PATCH/PUT /customers/1.json
def update
respond_to do |format|
if #customer.update(customer_params)
format.html { redirect_to #customer, notice: 'Customer was successfully updated.' }
format.json { render :show, status: :ok, location: #customer }
else
format.html { render :edit }
format.json { render json: #customer.errors, status: :unprocessable_entity }
end
end
end
# DELETE /customers/1
# DELETE /customers/1.json
def destroy
#customer.destroy
respond_to do |format|
format.html { redirect_to customers_url, notice: 'Customer was successfully destroyed.' }
format.json { head :no_content }
end
end
private
# Use callbacks to share common setup or constraints between actions.
def set_cliente
#cliente = Cliente.find(params[:id])
end
# Never trust parameters from the scary internet, only allow the white list through.
def customer_params
params.require(:customer).permit(:name, :address, :salesman_id)
end
end
***salesman***
class SalesmenController < ApplicationController
before_action :set_salesman, only: [:show, :edit, :update, :destroy]
# GET /salesmans
# GET /salesmans.json
def index
#salesmen = Salesman.all
end
# GET /salesmans/1
# GET /salesmans/1.json
def show
end
# GET /salesmans/new
def new
#salesman = Salesman.new
end
# GET /salesmans/1/edit
def edit
end
# POST /salesmans
# POST /salesmans.json
def create
#salesman = Salesman.new(salesman_params)
respond_to do |format|
if #salesman.save
format.html { redirect_to #salesman, notice: 'Salesman was successfully created.' }
format.json { render :show, status: :created, location: #salesman }
else
format.html { render :new }
format.json { render json: #salesman.errors, status: :unprocessable_entity }
end
end
end
# PATCH/PUT /salesmans/1
# PATCH/PUT /salesmans/1.json
def update
respond_to do |format|
if #salesman.update(salesman_params)
format.html { redirect_to #salesman, notice: 'Salesman was successfully updated.' }
format.json { render :show, status: :ok, location: #salesman }
else
format.html { render :edit }
format.json { render json: #salesman.errors, status: :unprocessable_entity }
end
end
end
# DELETE /salesmans/1
# DELETE /salesmans/1.json
def destroy
#salesman.destroy
respond_to do |format|
format.html { redirect_to salesmans_url, notice: 'Salesman was successfully destroyed.' }
format.json { head :no_content }
end
end
private
# Use callbacks to share common setup or constraints between actions.
def set_salesman
#salesman = Salesman.find(params[:id])
end
# Never trust parameters from the scary internet, only allow the white list through.
def salesman_params
params.require(:salesman).permit(:name, :address)
end
**invoice**
class InvoicesController < ApplicationController
before_action :set_invoice, only: [:show, :edit, :update, :destroy]
# GET /invoices
# GET /invoices.json
def index
#invoices = Invoice.all
end
# GET /invoices/1
# GET /invoices/1.json
def show
#invoice = Invoice.find(params[:id])
#ordenes = #invoice.ordenes
end
# GET /invoices/new
def new
#invoice = Invoice.new
end
# GET /invoices/1/edit
def edit
end
# POST /invoices
# POST /invoices.json
def create
#invoice = Invoice.new(invoice_params)
respond_to do |format|
if #invoice.save
format.html { redirect_to #invoice, notice: 'Invoice was successfully created.' }
format.json { render :show, status: :created, location: #invoice }
else
format.html { render :new }
format.json { render json: #invoice.errors, status: :unprocessable_entity }
end
end
end
# PATCH/PUT /invoices/1
# PATCH/PUT /invoices/1.json
def update
respond_to do |format|
if #invoice.update(invoice_params)
format.html { redirect_to #invoice, notice: 'Invoice was successfully updated.' }
format.json { render :show, status: :ok, location: #invoice }
else
format.html { render :edit }
format.json { render json: #invoice.errors, status: :unprocessable_entity }
end
end
end
# DELETE /invoices/1
# DELETE /invoices/1.json
def destroy
#invoice.destroy
respond_to do |format|
format.html { redirect_to invoices_url, notice: 'Invoice was successfully destroyed.' }
format.json { head :no_content }
end
end
private
# Use callbacks to share common setup or constraints between actions.
def set_invoice
#invoice = Invoice.find(params[:id])
end
# Never trust parameters from the scary internet, only allow the white list through.
def invoice_params
params.require(:invoice).permit(:date, :fid, :name, :address, :salesman_id)
end
end
-davefogo

Answer 1

Add the following to your views instead of what you currently have<%= customer.salesman.name if customer.salesman %>
This will ensure that you're not calling name when customer doesn't have a salesman.

Answer 2

Try this:
<% #customers.each do |customer| %>
<%= customer.name %>
<%= customer.address %>
<%= customer.salesman.try(:name) %>
<% end %>

Answer 3

Do this:
<% #customers.each do |customer| %>
<% Rails.logger.debug "\n\n#{#customers} has a nil customer in it\n\n" if customer.nil? %>
<% Rails.logger.debug "\n\nCustomer #{customer.id} has no salesman for [#{customer.salesman_id}]\n\n" if customer.salesman.nil? %>
<%= customer.name %>
<%= customer.address %>
<%= customer.salesman.name %>
<% end %>
...and then check your logs after hitting the index.