Help please. Through the ActiveAdmin resource, the nested model is not saved in the nested model in the console, it issues Unpermitted parameter :. Accordingly, the data of the remaining models are successfully saved.

In my case, it gives an error:

Situation with the code:

app / admin …

ActiveAdmin.register Landing do
permit_params
performances_attributes: [: id,: title,: name,: subtitle,: img],
time_performances_attributes: [: id,: time,: block]
form name: 'Landing page name' do | f |
   inputs 'Forum program block' do
    f.inputs do
     f.has_many: performances, new_record: true, allow_destroy: true do | r |
      r.input: title
      r.input: name
      r.input: subtitle
      r.input: img
      r.has_many: time_performances, new_record: true, allow_destroy: true do | rr |
       rr.input: time
       rr.input: block
      end
     end
    end
   end

/db/migrate/…time_performance

class CreateTimePerformances & lt; ActiveRecord :: Migration [6.0]
 def change
  create_table: time_performances do | t |
   t.string: time
   t.string: block
   t.belongs_to: landing
   t.belongs_to: performance
   t.timestamps
  end
 end
end

/ models / performance …

class Performance & lt; ApplicationRecord
  mount_uploader: img, ImageUploader
  belongs_to: landing
  has_many: time_performances
  accepts_nested_attributes_for: time_performances
end

/ models / time_performance …

class TimePerformance & lt; ApplicationRecord
  belongs_to: landing
  belongs_to: performance
end

/ models / landing

class Landing & lt; ApplicationRecord
  has_many: performances
  has_many: time_performances
  accepts_nested_attributes_for
                 : performances,
                 : time_performances

In a normal situation (controller), as I understand, they are used to transfer parameters for writing:

private
def param
 model attributes
end

Answer 1

If anyone has such a situation, remove the binding to the main database (Landing)

class TimePerformance & lt; ApplicationRecord
  belongs_to: performance
end
class CreateTimePerformances & lt; ActiveRecord :: Migration [6.0]
 def change
  create_table: time_performances do | t |
   t.string: time
   t.string: block
   t.belongs_to: performance
   t.timestamps
  end
 end
end

Answer 2, authority 100%

In the DSL of nested inputs, you use allow_destroy: true , which means you allow the user to delete nested entries. Under the hood, in this case, the hidden input : _destroy is used, which is sent to the server along with the usual fields. And it also needs to be placed in permit_params .

In your specific example, you need to write:

permit_params performances_attributes: [: id,: title,: name,: subtitle,: img,: _destroy],
       time_performances_attributes: [: id,: time,: block,: _destroy]