Question

我有

class CreateRoles < ActiveRecord::Migration 
  def change
    create_table :roles do |t|
      t.string :name

      t.timestamps
    end
  end
end

和

class Role < ActiveRecord::Base
  attr_accessible :name
  has_many :members, :posts
end

class Post < ActiveRecord::Base
  attr_accessible :content, :title, :role_id
  belongs_to :role
end

class Member < ActiveRecord::Base
  devise :database_authenticatable, :registerable,
         :recoverable, :rememberable, :trackable, :validatable, :lockable

  attr_accessible :role_id, :first_name, :last_name, :email, :password, :password_confirmation, :remember_me
end

在Rails控制台或seeds.rb中，我输入

Role.create(name: 'guest')

并获得错误

TypeError: can't convert Symbol into Integer
    from /usr/local/rvm/gems/ruby-1.9.3-p194/gems/activerecord-3.2.8/lib/active_record/associations/builder/collection_association.rb:35:in `[]'
    from /usr/local/rvm/gems/ruby-1.9.3-p194/gems/activerecord-3.2.8/lib/active_record/associations/builder/collection_association.rb:35:in `wrap_block_extension'
    from /usr/local/rvm/gems/ruby-1.9.3-p194/gems/activerecord-3.2.8/lib/active_record/associations/builder/collection_association.rb:22:in `build'
    from /usr/local/rvm/gems/ruby-1.9.3-p194/gems/activerecord-3.2.8/lib/active_record/autosave_association.rb:139:in `build'
    from /usr/local/rvm/gems/ruby-1.9.3-p194/gems/activerecord-3.2.8/lib/active_record/associations/builder/has_many.rb:10:in `build'
    from /usr/local/rvm/gems/ruby-1.9.3-p194/gems/activerecord-3.2.8/lib/active_record/associations/builder/collection_association.rb:13:in `build'
    from /usr/local/rvm/gems/ruby-1.9.3-p194/gems/activerecord-3.2.8/lib/active_record/associations.rb:1195:in `has_many'
    from /Users/ataylo9/Dropbox/Developer/hamsterdam/app/models/role.rb:3:in `<class:Role>'
    from /Users/ataylo9/Dropbox/Developer/hamsterdam/app/models/role.rb:1:in `<top (required)>'
    from /usr/local/rvm/gems/ruby-1.9.3-p194/gems/activesupport-3.2.8/lib/active_support/dependencies.rb:469:in `load'
    from /usr/local/rvm/gems/ruby-1.9.3-p194/gems/activesupport-3.2.8/lib/active_support/dependencies.rb:469:in `block in load_file'
    from /usr/local/rvm/gems/ruby-1.9.3-p194/gems/activesupport-3.2.8/lib/active_support/dependencies.rb:639:in `new_constants_in'
    from /usr/local/rvm/gems/ruby-1.9.3-p194/gems/activesupport-3.2.8/lib/active_support/dependencies.rb:468:in `load_file'
    from /usr/local/rvm/gems/ruby-1.9.3-p194/gems/activesupport-3.2.8/lib/active_support/dependencies.rb:353:in `require_or_load'
    from /usr/local/rvm/gems/ruby-1.9.3-p194/gems/activesupport-3.2.8/lib/active_support/dependencies.rb:502:in `load_missing_constant'
    from /usr/local/rvm/gems/ruby-1.9.3-p194/gems/activesupport-3.2.8/lib/active_support/dependencies.rb:192:in `block in const_missing'
    from /usr/local/rvm/gems/ruby-1.9.3-p194/gems/activesupport-3.2.8/lib/active_support/dependencies.rb:190:in `each'
    from /usr/local/rvm/gems/ruby-1.9.3-p194/gems/activesupport-3.2.8/lib/active_support/dependencies.rb:190:in `const_missing'
    from (irb):1
    from /usr/local/rvm/gems/ruby-1.9.3-p194/gems/railties-3.2.8/lib/rails/commands/console.rb:47:in `start'
    from /usr/local/rvm/gems/ruby-1.9.3-p194/gems/railties-3.2.8/lib/rails/commands/console.rb:8:in `start'
    from /usr/local/rvm/gems/ruby-1.9.3-p194/gems/railties-3.2.8/lib/rails/commands.rb:41:in `<top (required)>'
    from script/rails:6:in `require'

我知道我得到了错误，因为Rails想要建立会员和帖子的关系，但不应该只是将这些为零。我甚至尝试在seeds.rb中明确地将数组设置为nil，但是得到了相同的错误。

我没理解什么？谢谢！

更新：添加了帖子和会员模型以供参考

Answer 1

我使用相同的模型创建了相同的项目。而我发现这种描述关系就发生了错误。

class Role < ActiveRecord::Base
  attr_accessible :name
  has_many :members, :posts
end

我试过了：

class Role < ActiveRecord::Base
  attr_accessible :name
  has_many :members
  has_many :posts
end

class Post < ActiveRecord::Base
  attr_accessible :name, :role_id
  belongs_to :role
end

class Member < ActiveRecord::Base
  attr_accessible :name, :role_id
  belongs_to :role
end

一切正常。我不知道为什么但看起来像has_many：posts，：成员出现问题。但是你可以用不同的方式来解决这个问题。

Answer 2

jizak的回答是帮助我朝着正确的方向发展，从找到我自己问题的解决方案的角度来看。起初，我试图将多个“项目”添加到单个has_many中，如上例所示：

has_many：members，：posts

我的Rails控制台游戏我同样的错误 - “TypeError：无法将符号转换为整数。”所以我把它分成两行：

has_many：成员
has_many：帖子

现在它运作正常。

我想我试图变得有点过于聪明，认为关联（has_many）类似于attr_accessor / writer / reader - 其中可以向单个attr_x添加多个东西（或者在这种情况下，has_many）。 Rails的情况并非如此（据我所知） - 每个协会都需要自己的个人声明。

Answer 3

看起来您分配了不存在的关系（has_many：members，：posts）。你有这样的模特吗？模特有这样的关系吗？你可以发布会员和邮政模特的代码吗？

ActiveRecord :: Base＃create - TypeError：无法将Symbol转换为Integer

3 个答案: