活动记录销毁ArgumentError (参数数目错误(给定1，预期为0))：

Question

我正试图摧毁这样的购买对象

def destroy
        @purchase=current_user.purchases.where(flooding_property_id: params[:id])
        @purchase.destroy(flooding_property_id: params[:id])
    end

我知道这个错误是因为我有某种联系，但我似乎搞不清楚。我的模型如下

class FloodingProperty < ActiveRecord::Base
    has_many :purchases 
    has_many :users, through: :purchases
end

采购模型

class Purchase < ActiveRecord::Base

    belongs_to :user
    belongs_to :flooding_property
end

用户模型

class User < ActiveRecord::Base

  has_many :purchases
  has_many :carts
  has_many :flooding_properties, through: :purchases
end

数据库模式：

create_table "flooding_properties", force: :cascade do |t|
    t.string    "address"
    t.string    "zipcode"
    t.geography "latlon",       limit: {:srid=>4326, :type=>"point", :geographic=>true}
    t.datetime  "last_updated"
    t.datetime  "created_at",                                                            null: false
    t.datetime  "updated_at",                                                            null: false
  end

  add_index "flooding_properties", ["latlon"], name: "index_flooding_properties_on_latlon", using: :gist
  add_index "flooding_properties", ["zipcode"], name: "index_flooding_properties_on_zipcode", using: :btree

  create_table "purchases", force: :cascade do |t|
    t.boolean  "billed",               default: false
    t.integer  "user_id"
    t.integer  "flooding_property_id"
    t.datetime "created_at",                           null: false
    t.datetime "updated_at",                           null: false
  end

  add_index "purchases", ["billed"], name: "index_purchases_on_billed", where: "(billed = false)", using: :btree
  add_index "purchases", ["flooding_property_id"], name: "index_purchases_on_flooding_property_id", using: :btree
  add_index "purchases", ["user_id"], name: "index_purchases_on_user_id", using: :btree

  create_table "users", force: :cascade do |t|
    t.datetime "created_at",                          null: false
    t.datetime "updated_at",                          null: false
    t.string   "first_name"
    t.string   "last_name"
    t.string   "email",                  default: "", null: false
    t.string   "encrypted_password",     default: "", null: false
  end

Answer 1

你在一个实例上调用# single。这不是你的协会的问题。

def destroy
  current_user
    .purchases
    .find_by(flooding_property_id: params[:id])
    .destroy
end

我使用的是.find_by而不是.where，因为.where返回多个匹配。.find_by总是返回它找到的第一个。

如果确实想销毁所有匹配项，可以使用.where和.destroy_all：

def destroy
  current_user
    .purchases
    .where(flooding_property_id: params[:id])
    .destroy_all
end