## device.rb

class Device < ActiveRecord::Base
  validates_presence_of(:name, :message => "is required")
  validates_presence_of(:systemtype, :message => "is required")
  belongs_to :picture
  has_many :devicemodels,:dependent => :delete_all
  has_many :carmodels,:through => :devicemodels
  belongs_to :systemtype
  belongs_to :devicetype

  before_destroy :delete_associated_picture

  def self.get_random_product
    devices = Device.find(:all,:conditions => ['picture_id!=?',0])
    devices[rand(devices.size)]
  end

  def self.find_by_carbrand_id(id)
    devices = Device.find(:all)
    devices_array = []
    for device in devices
      for carmodel in device.carmodels
          print "======================"
          print "========test========" if carmodel.carbrand.id == id
      end
    end
    devices_array
  end


  private
   def delete_associated_picture
     picture.destroy if picture
   end
end

## devicemodel.rb

class Devicemodel < ActiveRecord::Base
  validates_presence_of(:carmodel, :message => "a carmodel is required")
  validates_presence_of(:device, :message => "a device is required")
  belongs_to :carmodel
  belongs_to :device
end

## carmodel.rb

 class Carmodel < ActiveRecord::Base

  validates_presence_of(:name, :message => "is required")
  validates_presence_of(:fromyear, :message => "is required")
  validates_presence_of(:toyear, :message => "is required")
  validates_presence_of(:carbrand, :message => "carbrand is required")

  belongs_to :picture
  belongs_to :carbrand
  has_many :devicemodels
  has_many :devices , :through => :devicemodels
  has_many :servicemodels
  has_many :services , :through => :servicemodels

  before_destroy :check_constraints
  after_destroy :delete_associated_picture


  def validate
    if fromyear
      if toyear
        errors.add("","From year should be earlier then To year") if fromyear>toyear
      else
        errors.add("","is required")
      end
    else
      errors.add("","is required")
    end
  end

  def self.startyear
    1985
  end

  def self.endyear
    DateTime::now().strftime("%Y").to_i
  end

private
  # check to see if there are childrecords ,
  # if so don't allow destroy
  def check_constraints
    devicemodels.count == 0
  end
  def delete_associated_picture
    Picture.destroy(picture_id)  if Picture.exists?(picture_id)
  end

end

## stacktrace

SystemStackError in Admin/devicesController#edit

stack level too deep
RAILS_ROOT: /Volumes/BACKUPS/Development/ruby/apps/motorecu

Application Trace | Framework Trace | Full Trace
vendor/plugins/will_paginate/lib/will_paginate/finder.rb:93:in `method_missing_without_paginate'
vendor/plugins/will_paginate/lib/will_paginate/finder.rb:93:in `method_missing'
app/controllers/admin/devices_controller.rb:67:in `edit'
/Library/Ruby/Gems/1.8/gems/actionpack-2.1.1/lib/action_controller/base.rb:1166:in `send'
/Library/Ruby/Gems/1.8/gems/actionpack-2.1.1/lib/action_controller/base.rb:1166:in `perform_action_without_filters'
/Library/Ruby/Gems/1.8/gems/actionpack-2.1.1/lib/action_controller/filters.rb:579:in `call_filters'
/Library/Ruby/Gems/1.8/gems/actionpack-2.1.1/lib/action_controller/filters.rb:572:in `perform_action_without_benchmark'
/Library/Ruby/Gems/1.8/gems/actionpack-2.1.1/lib/action_controller/benchmarking.rb:68:in `perform_action_without_rescue'
/Library/Ruby/Gems/1.8/gems/actionpack-2.1.1/lib/action_controller/benchmarking.rb:68:in `perform_action_without_rescue'
/Library/Ruby/Gems/1.8/gems/actionpack-2.1.1/lib/action_controller/rescue.rb:201:in `perform_action_without_caching'
/Library/Ruby/Gems/1.8/gems/actionpack-2.1.1/lib/action_controller/caching/sql_cache.rb:13:in `perform_action'
/Library/Ruby/Gems/1.8/gems/activerecord-2.1.1/lib/active_record/connection_adapters/abstract/query_cache.rb:33:in `cache'
/Library/Ruby/Gems/1.8/gems/activerecord-2.1.1/lib/active_record/query_cache.rb:8:in `cache'
/Library/Ruby/Gems/1.8/gems/actionpack-2.1.1/lib/action_controller/caching/sql_cache.rb:12:in `perform_action'
/Library/Ruby/Gems/1.8/gems/actionpack-2.1.1/lib/action_controller/base.rb:529:in `send'
/Library/Ruby/Gems/1.8/gems/actionpack-2.1.1/lib/action_controller/base.rb:529:in `process_without_filters'
/Library/Ruby/Gems/1.8/gems/actionpack-2.1.1/lib/action_controller/filters.rb:568:in `process_without_session_management_support'
/Library/Ruby/Gems/1.8/gems/actionpack-2.1.1/lib/action_controller/session_management.rb:130:in `process'
/Library/Ruby/Gems/1.8/gems/actionpack-2.1.1/lib/action_controller/base.rb:389:in `process'
/Library/Ruby/Gems/1.8/gems/activesupport-2.1.1/lib/active_support/dependencies.rb:503:in `load'
/Library/Ruby/Gems/1.8/gems/activesupport-2.1.1/lib/active_support/dependencies.rb:503:in `load'
/Library/Ruby/Gems/1.8/gems/activesupport-2.1.1/lib/active_support/dependencies.rb:355:in `new_constants_in'
/Library/Ruby/Gems/1.8/gems/activesupport-2.1.1/lib/active_support/dependencies.rb:503:in `load'
/Library/Ruby/Gems/1.8/gems/rails-2.1.1/lib/commands/servers/mongrel.rb:64
/Library/Ruby/Gems/1.8/gems/activesupport-2.1.1/lib/active_support/dependencies.rb:510:in `require'
/Library/Ruby/Gems/1.8/gems/activesupport-2.1.1/lib/active_support/dependencies.rb:355:in `new_constants_in'
/Library/Ruby/Gems/1.8/gems/activesupport-2.1.1/lib/active_support/dependencies.rb:510:in `require'
/Library/Ruby/Gems/1.8/gems/rails-2.1.1/lib/commands/server.rb:39
Request

Parameters:

{"id"=>"256"}
Show session dump

Response

Headers:

{"cookie"=>[],
 "Cache-Control"=>"no-cache"}