我希望能够为每个用户分配多个角色并使用 User.first.roles 之类的东西将它们取回,但我迷路了,你将如何使用 rails 控制台来做到这一点?我在模型中做错了什么?
u = User.first
User Load (0.1ms) SELECT "users".* FROM "users" LIMIT 1
=> #<User id: 18 [...]>
1.9.3-p194 :004 > u.roles
NameError: uninitialized constant User::Assignment
from [path]/ruby-1.9.3-p194/gems/activerecord-3.2.3/lib/active_record/inheritance.rb:119:in `compute_type'
from [path]/ruby-1.9.3-p194/gems/activerecord-3.2.3/lib/active_record/reflection.rb:172:in `klass'
from [path]/ruby-1.9.3-p194/gems/activerecord-3.2.3/lib/active_record/reflection.rb:385:in `block in source_reflection'
from [path]/ruby-1.9.3-p194/gems/activerecord-3.2.3/lib/active_record/reflection.rb:385:in `collect'
from [path]/ruby-1.9.3-p194/gems/activerecord-3.2.3/lib/active_record/reflection.rb:385:in `source_reflection'
from [path]/ruby-1.9.3-p194/gems/activerecord-3.2.3/lib/active_record/reflection.rb:508:in `check_validity!'
from [path]/ruby-1.9.3-p194/gems/activerecord-3.2.3/lib/active_record/associations/association.rb:26:in `initialize'
from [path]/ruby-1.9.3-p194/gems/activerecord-3.2.3/lib/active_record/associations/collection_association.rb:24:in `initialize'
from [path]/ruby-1.9.3-p194/gems/activerecord-3.2.3/lib/active_record/associations/has_many_through_association.rb:10:in `initialize'
from [path]/ruby-1.9.3-p194/gems/activerecord-3.2.3/lib/active_record/associations.rb:157:in `new'
from [path]/ruby-1.9.3-p194/gems/activerecord-3.2.3/lib/active_record/associations.rb:157:in `association'
from [path]/ruby-1.9.3-p194/gems/activerecord-3.2.3/lib/active_record/associations/builder/association.rb:44:in `block in define_readers'
from (irb):4
from [path]/ruby-1.9.3-p194/gems/railties-3.2.3/lib/rails/commands/console.rb:47:in `start'
from [path]/ruby-1.9.3-p194/gems/railties-3.2.3/lib/rails/commands/console.rb:8:in `start'
from [path]/ruby-1.9.3-p194/gems/railties-3.2.3/lib/rails/commands.rb:41:in `<top (required)>'
from script/rails:6:in `require'
from script/rails:6:in `<main>'
模型/用户.rb
class User < ActiveRecord::Base
attr_accessible :name, :email, :password, :password_confirmation, :role_id
has_many :assignments
has_many :roles, through: :assignments
#more code...
end
模型/角色.rb
class Role < ActiveRecord::Base
attr_accessible :name
has_many :assignments
has_many :users, through: :assignments
end
模型/assignments.rb
class Assignments < ActiveRecord::Base
attr_accessible :role_id, :user_id
belongs_to :user
belongs_to :role
end
schema.rb:http ://cl.ly/323n1t0Q1t390y1M2S0E