Reputation: 53
I'm banging my head against a Problem with AR Associations for 2 days now. I know there is a easy solution to this but I can't figure out.
I have two models Products and Users, that should be linked together. A Product should belong to a user and a user should have many products. I didn't manage to set the user variable in my controller, so I went for a habtm association. Here are the models:
User.rb
class User < ActiveRecord::Base
# Include default devise modules. Others available are:
#...
has_and_belongs_to_many :products
Product.rb
class Product < ActiveRecord::Base
has_many :product_images, :dependent => :destroy
accepts_nested_attributes_for :product_images, :allow_destroy => :true
has_and_belongs_to_many :users
products_controller.rb
class ProductsController < ApplicationController
def index
@products = Product.search(params[:search]).order(sort_column + ' ' + sort_direction).paginate(:per_page => 10, :page => params[:page])
respond_to do |format|
format.html # index.html.erb
format.json { render json: @products }
end
end
def new
@user = current_user
@product = Product.new#@user.products.build(params[:product])
@product.product_images.build
respond_to do |format|
format.html # new.html.erb
format.json { render json: @product }
end
end
def create
@user = current_user
@product = @user.products.build(params[:product])#Product.new(params[:product])
@product.product_images.build
@user.products << @product
respond_to do |format|
if @product.save
format.html { redirect_to @product, notice: 'Product was successfully created.' }
format.json { render json: @product, status: :created, location: @product }
else
format.html { render action: "new" }
format.json { render json: @product.errors, status: :unprocessable_entity }
end
end
end
_form.html.erb
<%= form_for @product, :html => {:multipart => true, :class => 'form-horizontal'} do |f| %>
schema.rb
....
create_table "products_users", :id => false, :force => true do |t|
t.integer "product_id"
t.integer "user_id"
end
....
So, even I know, there should be a one-to-many association between user and product, this works out for me. In IRB, I can do this:
u = User.first
u.products
with the habtm association I can even do it viseversa:
p = Product.first
p.users
But I can't access the user attributes:
p.users.username:
NoMethodError: User Load (2.0ms) SELECT "users".* FROM "users" INNER JOIN "products_users" ON "users"."id" = "products_users"."user_id" WHERE "products_users"."product_id" = 12
Could anybody be so nice to help me out of this? What am I doing wrong?
Thanks a lot! Your help would save my weekend!
EDIT: Here's my controller action for the one-to-many relation:
class ProductsController < ApplicationController
helper_method :sort_column, :sort_direction
def index
@products = Product.search(params[:search]).order(sort_column + ' ' + sort_direction).paginate(:per_page => 10, :page => params[:page])
respond_to do |format|
format.html # index.html.erb
format.json { render json: @products }
end
end
def show @product = Product.find(params[:id]) @images = @product.product_images respond_to do |format| format.html # show.html.erb format.json { render json: @product } end end
def new
@user = current_user
@product = Product.new#@user.products.build(params[:product])
@product.product_images.build
#3.times { @product.product_images.build }
respond_to do |format|
format.html # new.html.erb
format.json { render json: @product }
end
end
def edit
@product = Product.find(params[:id])
@product.product_images.build
end
def create
@user = current_user
@product = @user.products.build(params[:product])#Product.new(params[:product])
@product.product_images.build
respond_to do |format|
if @product.save
format.html { redirect_to @product, notice: 'Product was successfully created.' }
format.json { render json: @product, status: :created, location: @product }
else
format.html { render action: "new" }
format.json { render json: @product.errors, status: :unprocessable_entity }
end
end
end
def update
@product = Product.find(params[:id])
respond_to do |format|
if @product.update_attributes(params[:product])
format.html { redirect_to @product, notice: 'Product was successfully updated.' }
format.json { head :no_content }
else
format.html { render action: "edit" }
format.json { render json: @product.errors, status: :unprocessable_entity }
end
end
end
def destroy
@product = Product.find(params[:id])
@product.destroy
respond_to do |format|
format.html { redirect_to products_url }
format.json { head :no_content }
end
end
private
def sort_column
Product.column_names.include?(params[:sort]) ? params[:sort] : "created_at"
# params[:sort] || "created_at"
end
def sort_direction
%w[asc desc].include?(params[:direction]) ? params[:direction] : "asc"
# params[:direction] || "asc"
end
end
EDIT2: Schema.rb
create_table "products", :force => true do |t|
t.string "title"
t.string "description"
t.string "testimonial"
t.decimal "credits", :precision => 3, :scale => 0
t.datetime "created_at", :null => false
t.datetime "updated_at", :null => false
t.decimal "age"
t.string "condition"
t.string "product_image"
t.string "image"
t.integer "user_id"
end
create_table "users", :force => true do |t|
t.string "email", :default => "", :null => false
t.string "encrypted_password", :default => "", :null => false
t.string "reset_password_token"
t.datetime "reset_password_sent_at"
t.datetime "remember_created_at"
t.integer "sign_in_count", :default => 0
t.datetime "current_sign_in_at"
t.datetime "last_sign_in_at"
t.string "current_sign_in_ip"
t.string "last_sign_in_ip"
t.datetime "created_at", :null => false
t.datetime "updated_at", :null => false
t.string "username"
t.integer "product_id"
end
Upvotes: 2
Views: 447
Reputation: 10405
Don't use a has_and_belongs_to_many
if you have a one-to-many relation. Creating and maintaining another table is adding too much complexity. My advice would be to figure out why you can't make the one-to-many relation working.
You should be able to make this work :
class User < ActiveRecord::Base
has_many :products #Plural
end
class Product < ActiveRecord::Base
belongs_to :user #Singular
end
If it doesn't work, copy/paste your controller code that you use for one-to-many relation!
Good luck
Upvotes: 1
Reputation: 46675
Because Product
has many users
, p.users
is an array-like object. You need p.users[0].username
.
But why can't you make it a standard one-to-many association?
Upvotes: 0