Rails server saying rollback transcation when clicking add to cart - ruby-on-rails

Question

Just started learning ruby on rails, and i created a simple shopping cart application but when i click "add to cart", i get a rollback transaction from my server. I believe the error has something to do with my orderitem controller but not sure how to fix this issue here my code.
rails server
Started POST "/order_items" for 127.0.0.1 at 2017-10-25 10:47:44 -0400
Processing by OrderItemsController#create as JS
Parameters: {"utf8"=>"✓", "order_item"=>{"product_id"=>"13", "quantity"=>"1"}, "commit"=>"Add to cart"}
(0.0ms) begin transaction
Product Load (0.5ms) SELECT "products".* FROM "products" WHERE "products"."id" = ? LIMIT ? [["id", 13], ["LIMIT", 1]]
(0.0ms) rollback transaction
Rendering order_items/create.js.erb
Rendered order_items/create.js.erb (0.5ms)
Completed 200 OK in 1028ms (Views: 605.5ms | ActiveRecord: 0.5ms)
order_items_controller.rb
class OrderItemsController < ApplicationController
def create
#order = current_order
#order_item = #order.order_items.new(order_item_params)
#order.save
session[:order_id] = #order.id
end
def update
#order = current_order
#order_item = #order.order_items.new(order_item_params)
#order_item.update_attributes(order_item_params)
#order_items = #order.order_items
end
def destroy
#order = current_order
#order_item = #order.order_items.find(params[:id])
#order_item.destroy
#order_items = #order.order_items
end
private
def order_item_params
params.require(:order_item).permit(:product_id, :quantity)
end
end
create.js.erb
<% if #order.errors.any? || #order_item.errors.any? %>
alert("Invalid")
<% else %>
$(".cart").html("<%= escape_javascript(render 'layouts/cart') %>")
<% end %>
schema.rb
ActiveRecord::Schema.define(version: 20171019015705) do
create_table "order_items", force: :cascade do |t|
t.integer "product_id"
t.integer "order_id"
t.integer "quantity"
t.float "total_price"
t.float "unit_price"
t.datetime "created_at", null: false
t.datetime "updated_at", null: false
end
create_table "orders", force: :cascade do |t|
t.float "subtotal"
t.float "total"
t.float "shipping"
t.datetime "created_at", null: false
t.datetime "updated_at", null: false
t.integer "user_id"
end
create_table "products", force: :cascade do |t|
t.string "name"
t.datetime "created_at", null: false
t.datetime "updated_at", null: false
t.float "price"
t.text "description"
t.string "picture"
end
create_table "users", force: :cascade 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, null: false
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.string "username"
t.datetime "created_at", null: false
t.datetime "updated_at", null: false
t.index ["email"], name: "index_users_on_email", unique: true
t.index ["reset_password_token"], name: "index_users_on_reset_password_token", unique: true
end
end
orderItem.rb
class OrderItem < ApplicationRecord
belongs_to :order
belongs_to :product
before_save :set_unit_price
before_save :set_total_price
def unit_price
if persisted?
self[:unit_price]
else
product.price
end
end
def total_price
unit_price * quantity
end
private
def set_unit_price
self[:unit_price] = unit_price
end
def set_total_price
self[:total_price] = quantity * set_unit_price
end
end
order.rb
class Order < ApplicationRecord
has_many :order_items
belongs_to :user
before_save :set_subtotal
def subtotal
order_items.collect {|order_item| order_item.valid? ? (order_item.unit_price*order_item.quantity) : 0}.sum
end
private
def set_subtotal
self[:subtotal] = subtotal
end
end
user.rb
class User < ApplicationRecord
# Include default devise modules. Others available are:
# :confirmable, :lockable, :timeoutable and :omniauthable
devise :database_authenticatable, :registerable,
:recoverable, :rememberable, :trackable, :validatable
has_many :orders
def to_param
username
end
end
carts_controller.rb
class CartsController < ApplicationController
before_action :authenticate_user!
def show
#order_items = current_order.order_items
end
end
Rails Server now
Started GET "/products" for 127.0.0.1 at 2017-10-25 11:21:11 -0400
Processing by ProductsController#index as HTML
Rendering products/index.html.erb within layouts/application
Product Load (0.0ms) SELECT "products".* FROM "products"
Rendered products/index.html.erb within layouts/application (16.0ms)
User Load (0.5ms) SELECT "users".* FROM "users" WHERE "users"."id" = ? ORDER BY "users"."id" ASC LIMIT ? [["id", 1], ["LIMIT", 1]]
Rendered layouts/_cart.html.erb (1.0ms)
Rendered layouts/_nav.html.erb (34.3ms)
Completed 200 OK in 604ms (Views: 571.1ms | ActiveRecord: 0.5ms)

Answer 1

#order_item = #order.order_items.new(order_item_params)
is creating an item only in memory. there is nothing wrong with that.but i think you need to change the new to create as so
#order_item = #order.order_items.create(order_item_params)