Ruby on rails rails验证在更新中接受\u嵌套的\u属性，\u和habtm关联重置关联

在rails 2.3.8中，如果我在验证过程中循环甚至检查habtm关联，那么在接受嵌套属性关联的情况下，我在验证时会遇到问题，课程会被加载，任何更新都会丢失。例如，我有以下模式：

ActiveRecord::Schema.define(:version => 20100829151836) do

 create_table "attendees", :force => true do |t|
  t.integer  "lesson_set_id"
  t.string   "name"
  t.datetime "created_at"
  t.datetime "updated_at"
 end

 create_table "lesson_sets", :force => true do |t|
  t.datetime "created_at"
  t.datetime "updated_at"
 end 

 create_table "lesson_sets_lessons", :id => false, :force => true do |t|
  t.integer "lesson_id"
  t.integer "lesson_set_id"
 end

 create_table "lessons", :force => true do |t|
  t.integer  "activity_id"
  t.integer  "limit"
  t.datetime "created_at"
  t.datetime "updated_at"
 end
end

以及以下型号：

class Attendee < ActiveRecord::Base
 belongs_to :lesson_sets
end
class Lesson < ActiveRecord::Base
 has_and_belongs_to_many :lesson_sets
end
class LessonSet < ActiveRecord::Base
 has_and_belongs_to_many :lessons
 has_many :attendees
 accepts_nested_attributes_for :lessons
 validate do |lesson_set|
  lesson_set.lessons.each do |l| 
   if l.limit < attendees.count
    self.errors.add_to_base("Sorry only #{l.limit} people allowed on lesson")
   end
  end
 end
end

课堂参与者

如果我称之为：

>> ls = LessonSet.first
=> #<LessonSet id: 1, created_at: "2010-08-29 07:50:23", updated_
at: "2010-08-29 07:50:23">
>> Lesson.last
=> #<Lesson id: 1, activity_id: 29, created_at: "2010-08-29 07:57:13", updated_a
t: "2010-08-29 17:04:34", limit: 5>
params = {"lessons_attributes"=>{"0"=>{"activity_id"=>"3", "id"=>"1", "_destroy"=>""}}, "id"=>"1"}
=> {"id"=>"1", "lessons_attributes"=>{"0"=>{"activity_id"=>"3", "id"=>"1", "_des
troy"=>""}}}
>> ls.update_attributes(params)
=> true
>> Lesson.last
=> #<Lesson id: 1, activity_id: 29, created_at: "2010-08-29 07:57:13", updated_a
t: "2010-08-29 17:04:34", limit: 5>
>> params = {"lessons_attributes"=>{"0"=>{"activity_id"=>"29", "id"=>"1", "_de>
=> {"id"=>"1", "lessons_attributes"=>{"0"=>{"activity_id"=>"29", "id"=>"1", "_de
stroy"=>""}}}
>> ls.update_attributes(params)
=> true
<y_id"=>"3", "id"=>"1", "_destroy"=>""}}, "id"=>"1"}
=> {"id"=>"1", "lessons_attributes"=>{"0"=>{"activity_id"=>"3", "id"=>"1", "_des
troy"=>""}}}
>> Lesson.last
=> #<Lesson id: 1, activity_id: 29, created_at: "2010-08-29 07:57:13", updated_a
t: "2010-08-29 17:04:34", limit: 5>
>> ls.update_attributes(params)
=> true
>> Lesson.last
=> #<Lesson id: 1, activity_id: 3, created_at: "2010-08-29 07:57:13", updated_at
: "2010-08-29 17:13:36", limit: 5>

>ls=LessonSet.first
=> #
>>最后一课
=> #
参数={“课程属性”=>{“0”=>{“活动id”=>“3”，“id”=>“1”，“销毁”=>“}}”，id“=>“1”}
=>{“id”=>“1”，“课程属性”=>{“0”=>{“活动id”=>“3”，“id”=>“1”，“课程属性”
特洛伊“=>”}}
>>ls.更新_属性（参数）
=>正确
>>最后一课
=> #
>>参数={“课程属性”=>{“0”=>{“活动id”=>“29”，“id”=>“1”，“de>
=>{“id”=>“1”，“课程属性”=>{“0”=>{“活动id”=>“29”，“id”=>“1”，“\u de”
stroy“=>”}}
>>ls.更新_属性（参数）
=>正确
使用上述型号

课程有并且属于许多课程集

与会者属于课程集

尝试验证参与者不应超过限制意味着在保存新关联之前，在验证期间重置了课程和课程集之间的关联

将验证逻辑从课程集移动到与会者可以使验证工作正常

因此，如果您有类似的问题，请尝试将验证逻辑从连接模型移动到它连接的其中一个模型