Ruby-on-rails-seed.rb:'&引用；命名错误：未定义的方法'each'；至于；

我是RoR的新手，如果我不能清楚地表达自己，我很抱歉。对于因张贴代码而非图片而造成的不便，我深表歉意（qwq没有足够的声誉） 我的数据库的模式如下所示

ActiveRecord::Schema.define(version: 20200323173103) do

  create_table "posts", force: :cascade do |t|
    t.string   "title"
    t.text     "content"
    t.datetime "created_at", null: false
    t.datetime "updated_at", null: false
    t.integer  "uid"
    t.integer  "student_id"
  end

  add_index "posts", ["student_id"], name: "index_posts_on_student_id"


  create_table "users", force: :cascade do |t|
    t.string   "name"
    t.integer  "year"
    t.datetime "created_at", null: false
    t.datetime "updated_at", null: false
    t.integer  "uid"
    t.integer  "student_id"
  end
  add_index "users", ["student_id"], name: "index_users_on_student_id"


  create_table "students", force: :cascade do |t|
    t.string   "name"
    t.string   "password_digest"
    t.datetime "created_at",      null: false
    t.datetime "updated_at",      null: false
  end

end

和我的seed.rb文件：

Student.destroy_all
Post.destroy_all
User.destroy_all

Post.create!([
  { title: "hello world", content: "first web app." },
  { title: "Severus Snape", content: "Always." },
  { title: "Albus Dumbledore", content: "'I am not worried, Harry,' said Dumbledore, his voice a little stronger despite the freezing water.' I am with you.'" },
  { title: "Albus Dumbledore", content: "“But you know, happiness can be found even in the darkest of times, if one only remembers to turn on the light." },
  { title: "Hermione Granger", content: "'I hope you are pleased with yourselves. We could all have been killed — or worse, expelled. Now if you don't mind, I'm going to bed.'" },
  { title: "Albus Dumbledore", content: "It does not do well to dwell on dreams and forget to live." },
  { title: "Ron Weasley", content: "You're a little scary sometimes, you know that? Brilliant ... but scary." },
  { title: "Rubeus Hagrid", content: "Yer a wizard Harry." },
  { title: "Dobby", content: "Dobby is free." },
  { title: "Gilderoy Lockhart", content: "Fame is a fickle friend, Harry. Celebrity is as celebrity does. Remember that." },
  { title: "Harry Potter", content: "I solemnly swear I am up to no good." }
])

users = User.create!([
    { uid:1, name: "zyj",year: 2000 },
    { uid:2, name: "jz zhou",year: 1995 },
    { uid:3, name: "mitty",year: 2002 },
    { uid:4, name: "stela",year: 1985 },
    { uid:5, name: "someone",year: 1993 },
    { uid:6, name: "you know who",year: 1863}

])

students = Student.create! ([
  { name: "Joe", password: "abc123" },
  { name: "Jim", password: "123abc" },
  { name: "zyj", password: "0303267337" },
  { name: "Joseph", password: "123456" }
])

Post.all.each do |p|
  p.uid = users.sample.uid
  p.save!
end

User.all.each do |u|
  @sid = students.sample.id
  u.student_id = @sid
  Post.find_by(uid: u.uid).each do |po|
        po.student_id = @sid
        po.save!
  end
  u.save!
end

当我运行“rake db:seed”时，它会抛出下面的错误消息：

jhzhengtekiMacBook-Air:my_博客severina$rake-db:seed
雷克流产了！
NoMethodError：未定义的方法“each”#
/Users/severina/Desktop/my_blog/db/seeds.rb:52:in'block in'
/Users/severina/Desktop/my_blog/db/seeds.rb:49:in`'
任务：TOP=>db:seed
（通过使用--trace运行任务查看完整跟踪）

那么49号线和52号线发生了什么？ 谢谢你的帮助

返回一个对象（或

nil

），您试图对其使用

每个

进行迭代，该对象应可用于枚举

您可以将块更改为

po=Post.find_by（uid:u.uid）
po.student_id=@sid
阿宝，救命！

如果您想处理单个对象，但是如果您想通过该uid更改所有帖子，则应使用

where

Post.where（uid:u.uid）。每个do|po|
po.student_id=@sid
阿宝，救命！
结束

返回一个对象（或

nil

），您试图对该对象使用

每个

进行迭代，该对象应可用于枚举

您可以将块更改为

po=Post.find_by（uid:u.uid）
po.student_id=@sid
阿宝，救命！

如果您想处理单个对象，但是如果您想通过该uid更改所有帖子，则应使用

where

Post.where（uid:u.uid）。每个do|po|
po.student_id=@sid
阿宝，救命！
结束

您发布的是代码而不是图像，这很好，所以这一切都很完美！你发布代码而不是图片，这很好，所以这一切都很完美！

jhzhengtekiMacBook-Air:my_blog severina$ rake db:seed
rake aborted!
NoMethodError: undefined method `each' for #<Post:0x00007fe59cdd8bd0>
/Users/severina/Desktop/my_blog/db/seeds.rb:52:in `block in <top (required)>'
/Users/severina/Desktop/my_blog/db/seeds.rb:49:in `<top (required)>'
Tasks: TOP => db:seed
(See full trace by running task with --trace)