Rails 关联不起作用,user_id 未显示在控制台中
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【中文标题】Rails 关联不起作用,user_id 未显示在控制台中【英文标题】:Rails Associations Not working, user_id not showing in console 【发布时间】:2016-08-04 12:46:12 【问题描述】:在控制台中我收到此错误:
peegin.user
NameError: undefined local variable or method `peegin' for main:Object
Did you mean? @peegin
另外,当我尝试在控制台中访问 Peegin 时,它不显示 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
【问题讨论】:
【参考方案1】:确保您的数据库是最新的。
$ bin/rake db:migrate
然后.. 你必须创建一个 Peegin 对象,然后你才能访问用户:
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
【讨论】:
试过了。仍然收到错误'NoMethodError:未定义的方法user' for #<Peegin:0x007fb61a530de0> from /Users/Amani/.rvm/gems/ruby-2.3.0/gems/activemodel-4.2.6/lib/active_model/attribute_methods.rb:433:in
method_missing''
是的,我得到了这个 bin/rake db:migrate 在进程 26378 /Users/Amani/.rvm/gems/ruby-2.3.0/gems/spring-1.7 中通过 Spring 预加载器运行.2/lib/spring/application.rb:175:警告:PATH 中不安全的世界可写目录 /usr/local,模式 040777【参考方案2】:
请在您的 Rails 控制台中尝试以下操作:
@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
代替
peegin.user
【讨论】:
谢谢它现在似乎可以工作了。我关闭了 Rails 服务器并重新启动它,一切都开始工作了。以上是关于Rails 关联不起作用,user_id 未显示在控制台中的主要内容,如果未能解决你的问题,请参考以下文章
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