ruby-on-rails - Rails - has_many 关系导致 NoMethodError

Question

我有以下迁移和模型：

class CreatePlatforms < ActiveRecord::Migration
  def change
    create_table :platforms do |t|

        t.integer :user_id
        t.string :name
        t.string :platform_id
        t.timestamps
    end
  end
end

class CreateUsers < ActiveRecord::Migration
  def change
    create_table :users do |t|

        t.string :email
        t.string :first_name
        t.string :last_name
        t.string :gender
        t.date :birthday
        t.timestamps
    end
  end
end

class Platform < ActiveRecord::Base
    belongs_to :user
end

class User < ActiveRecord::Base
    attr_accessible :email, :first_name, :last_name, :gender, :birthday
    has_many :platforms
end

有了这个定义，我可以创建用户和平台：

user = User.new
platform1 = Platform.new
platform2 = Platform.new

甚至我可以将用户与平台相关联：

platform1.user = user

但是，当我尝试将平台与用户关联或从用户那里获取平台时，它会崩溃：

user.platforms << user or user.platforms
NoMethodError: undefined method `platforms' for #<User:0x007f8cfd47a770>

Answer 1

事实证明，问题出在数据库字段platform_id上。这弄乱了轨道。只需将其删除即可。