gistfile1.rb

class Grid < ActiveRecord::Base
  has_many   :rows
  has_many   :columns
  has_many   :cells, :through => :rows
  
  accepts_nested_attributes_for :rows,
    :allow_destroy => true,
    :reject_if => lambda {|a| a[:description].blank? }
  accepts_nested_attributes_for :columns,
    :allow_destroy => true,
    :reject_if => lambda {|a| a[:description].blank? }
end


class Column < ActiveRecord::Base
  belongs_to :grid
  has_many :cells, :dependent => :destroy
  has_many :rows, :through => :grid
end


class Row < ActiveRecord::Base
  belongs_to :grid
  has_many   :cells, :dependent => :destroy
  has_many   :columns, :through => :grid
  
  accepts_nested_attributes_for :cells
end


class Cell < ActiveRecord::Base
  belongs_to :row
  belongs_to :column
  has_one    :grid, :through => :row
end