Question

我正在尝试在我的应用程序中建立关系，以便：

a broadcast has 0..1 post and 0..1 jobs

我已经研究过belongs_to和has_one，我试图实现这些，我在我的应用程序中这样做的其他例子正在工作，所以我无法弄清楚为什么这不是。< / p>

这是我的posts和jobs表格

class CreateJobs < ActiveRecord::Migration
  def change
    create_table :jobs do |t|
      t.text :title, null: :no #Must have a title
      t.string :content, default: 'No content specified'
      t.references :broadcast, null: :no, index: true  # Must have been broadcast
      t.timestamps
    end
  end
end

class CreatePosts < ActiveRecord::Migration
  def change
    create_table :posts do |t|
      t.text :title, null: :no #Must have a title
      t.string :content, default: 'No content specified'
      t.references :broadcast, null: :no, index: true  # Must have been broadcast
      t.timestamps  # Created at will double up as post date
    end
  end
end

这是关系的broadcast.rb，job.rb，post.rb定义

class Post < ActiveRecord::Base

  #A post makes no sense without a title and content, they must exits.
  validates_presence_of :title, :content

  belongs_to :broadcast
end

class Job < ActiveRecord::Base

  #A job makes no sense without a title and content, they must exits.
  validates_presence_of :title, :content

  belongs_to :broadcast
end

class Broadcast < ActiveRecord::Base

  # The only restriction is that broadcasts must have some data to
  # be valid and an associated broadcaster (user_id)
  validates_presence_of :content, :title

  # 0..1 relationship between job/post and broadcast
  has_one :post
  has_one :job
end

这是schema.rb

之后的db:migrate

create_table "broadcasts", force: true do |t|
    t.text     "title"
    t.text     "content"
    t.boolean  "jobs",       default: false
    t.boolean  "general",    default: false
    t.integer  "user_id"
    t.datetime "created_at"
    t.datetime "updated_at"
  end

add_index "jobs", ["broadcast_id"], name: "index_jobs_on_broadcast_id"

  create_table "posts", force: true do |t|
    t.text     "title"
    t.string   "content",      default: "No content specified"
    t.integer  "broadcast_id"
    t.datetime "created_at"
    t.datetime "updated_at"
  end

  add_index "posts", ["broadcast_id"], name: "index_posts_on_broadcast_id"

  create_table "user_details", force: true do |t|
    t.string  "login",            limit: 40
    t.string  "salt",             limit: 40
    t.string  "crypted_password", limit: 40
    t.integer "user_id"
  end

这是seeds.rb文件

broadcast = Broadcast.create!(title: 'seed title 1 Broadcast', content: 'seeded Broadcast', jobs: true, general: true,
                              user: user)

 Post.create!(title: 'seed title 1', content: "#{broadcast.content}", broadcast: broadcast)

 broadcast2 = Broadcast.create!(title: 'seed title 2 Broadcast', content: 'Another seeded broadcast', general: true,
                              user: user)

 broadcast3 = Broadcast.create!(title: 'seed title 3 Broadcast', content: 'Another seeded broadcast', jobs: true,
                                                           user: user)

 Post.create!(title: 'seed title 2', content: "#{broadcast2.content}", broadcast: broadcast2)

 Job.create!(title: 'seed title 1 job', content: "#{broadcast.content}", broadcast: broadcast2)
 Job.create!(title: 'seed title 2 job', content: "#{broadcast2.content}", broadcast: broadcast3)

这是从rake db:seed

引发的错误消息

我已经在SQL资源管理器中检查了数据库并且表格确实存在，我不确定为什么会出现此错误。

rake aborted!
ActiveRecord::UnknownAttributeError: unknown attribute: broadcast

在这一行：

 Post.create!(title: 'seed title 1', content: "#{broadcast.content}", broadcast: broadcast)

如果您需要更多代码，请问我。毫无疑问，我错过了一些明显的东西，但做这样的事情在我的其他项目中起作用。

谢谢，克里斯。

尝试填充外键字段时rake db：种子抛出属性未找到错误

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