Rails的协会不工作，在控制台USER_ID不显示

Question

在控制台中我得到这个错误：

peegin.user 
NameError: undefined local variable or method `peegin' for main:Object 
Did you mean? @peegin 

还当我尝试访问Peegin控制台不显示user_id：

Peegin 
=> Peegin(id: integer, title: string, meaning: string, example: string, created_at: datetime, updated_at: datetime, permalink: string) 
2.3.0 :039 > 

用户类

class User < ActiveRecord::Base 
# Include default devise modules. Others available are: 
# :confirmable, :lockable, :timeoutable and :omniauthable 
devise :database_authenticatable, :registerable, 
    :recoverable, :rememberable, :trackable, :validatable 

has_many :peegins 
end 

Peegin类

class Peegin < ActiveRecord::Base 
belongs_to :user 
before_create :generate_permalink 
def to_param 
    permalink 
end 



private 

def generate_permalink 
    pattern=self.title.parameterize 
    duplicates = Peegin.where(permalink: pattern) 

    if duplicates.present? 
     self.permalink = "#{pattern}-#{duplicates.count+1}" 
    else 
     self.permalink = self.title.parameterize 
    end 

end 

end 

架构

ActiveRecord::Schema.define(version: 20160804115242) do 
create_table "peegins", force: :cascade do |t| 
t.string "title" 
t.string "meaning" 
t.string "example" 
t.datetime "created_at", null: false 
t.datetime "updated_at", null: false 
t.string "permalink" 
t.integer "user_id" 
end 

add_index "peegins", ["user_id"], name: "index_peegins_on_user_id", unique: true 

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.datetime "created_at",       null: false 
t.datetime "updated_at",       null: false 
t.string "name" 
end 

add_index "users", ["email"], name: "index_users_on_email", unique: true 
add_index "users", ["reset_password_token"], name:  "index_users_on_reset_password_token", unique: true 

end 

Answer 1

确保数据库是最新的。

$ bin/rake db:migrate 

然后..你必须创建一个Peegin对象，然后就可以访问用户：

peegin = Peegin.create(title: "something") 
peegin.user # => nil 
peegin.user = User.first # Or take any user you want. 
peegin.save # => user_id is updated in the database 

Answer 2

在Rails控制台，请试试这个：

@peegin = Peegin.find(1) //IF one doesn't work make sure if database has a record with this id and try with id that exists. 

然后使用

@peegin.user 

而不是

peegin.user