ruby - Rails "undefined method for ActiveRecord_Associations_CollectionProxy" -

i have models:

class student < activerecord::base      has_many :tickets     has_many :movies, through: :tickets  end   class movie < activerecord::base      has_many :tickets, dependent: :destroy     has_many :students, through: :tickets     belongs_to :cinema  end   class ticket < activerecord::base      belongs_to :movie, counter_cache: true     belongs_to :student  end   class cinema < activerecord::base      has_many :movies, dependent: :destroy     has_many :students, through: :movies      has_many :schools, dependent: :destroy     has_many :companies, through: :yard_companies  end   class school < activerecord::base       belongs_to :company     belongs_to :student     belongs_to :cinema, counter_cache: true  end   class teacher < activerecord::base      belongs_to :movie, counter_cache: true     belongs_to :company  end   class contract < activerecord::base      belongs_to :company     belongs_to :student  end   class company < activerecord::base      has_many :teachers     has_many :movies, through: :teachers      has_many :contracts     has_many :students, through: :contracts  end 

if write in movies_controller.rb:

@students = @movie.cinema.companies.students.all

i have error:

undefined method 'students' #company::activerecord_associations_collectionproxy:0x00000007f13d88>

if instead write this:

@students = @movie.cinema.companies.find(6).students.all

it shows me correct students in select_collection.

how better understand process?

update:

i need collection_select of every students in companies of cinema of movie.

how write?

as described nermin you're trying request collection of children, collection of children.

you use collect gather students companies along lines of:

@movie.cinema.companies.collect(&:students).flatten.uniq 

but think better add scope student model along lines of:

scope :for_companies, ->(_companies) {joins(:companies).where(company: _companies)} 

called student.for_companies(@movie.cinema.companies)

disclaimer: untested, should starting point!