Question

offer = Offer.first
  Offer Load (0.3ms)  SELECT  "offers".* FROM "offers" ORDER BY "offers"."id" ASC LIMIT ?  [["LIMIT", 1]]
 => #<Offer id: 1, name: "goa trip", description: "2 days", vendor_id: 1, created_at: "2016-10-12 08:57:14", updated_at: "2016-10-12 08:57:14"> 
2.2.3 :014 > offer.coupons.create(coupon_code: "1245343")
   (0.1ms)  begin transaction
   (0.1ms)  commit transaction
 => #<Coupon id: nil, coupon_code: "1245343", offer_id: 1, user_id: nil, created_at: nil, updated_at: nil> 
2.2.3 :015 > Coupon.all
  Coupon Load (0.1ms)  SELECT "coupons".* FROM "coupons"
 => #<ActiveRecord::Relation []>

以下是模型方面的关系

class Vendor < ApplicationRecord
    has_many :offers
end

class Offer < ApplicationRecord
    has_many :coupons
  belongs_to :vendor
end

class Coupon < ApplicationRecord
  belongs_to :offer
  belongs_to :user
end

这是架构

create_table "vendors", force: :cascade do |t|
    t.string   "name"
    t.string   "company_name"
    t.datetime "created_at",   null: false
    t.datetime "updated_at",   null: false
  end
create_table "offers", force: :cascade do |t|
    t.string   "name"
    t.string   "description"
    t.integer  "vendor_id"
    t.datetime "created_at",  null: false
    t.datetime "updated_at",  null: false
    t.index ["vendor_id"], name: "index_offers_on_vendor_id"
  end

create_table "coupons", force: :cascade do |t|
    t.string   "coupon_code"
    t.integer  "offer_id"
    t.integer  "user_id"
    t.datetime "created_at",  null: false
    t.datetime "updated_at",  null: false
    t.index ["offer_id"], name: "index_coupons_on_offer_id"
    t.index ["user_id"], name: "index_coupons_on_user_id"
  end

如果我以错误的方式使用这种关系，请告诉我。感谢

Answer 1

正在运行

offer.coupons.create!(coupon_code: "1245343")

将显示验证错误。

我的假设是，您必须指定user_id，因为您拥有并索引index_coupons_on_user_id。

在Rails 5中 - 引用模型时，会自动创建foreign_key的索引。

你有2个foreign_keys：

offer_id
user_id

因此，创建了两个指数。

值未插入，但提交正在进行

1 个答案: