gistfile1.r

DataMapper.auto_migrate!
(1..5).each do |n|
  PlantType.create(:nome => "nome_#{n}")
  ComponentType.create(:nome => "nome_#{n}")
  Supplier.create(:nome => "nome_#{n}")
  Component.create(:nome => "nome_#{n}", :supplier => Supplier.first, :component_type => ComponentType.first)
end

params = {:supplier=> Supplier.get(1), :component_type => ComponentType.get(1), :nome => "ciao", :plant_types => PlantType.all(:id => "3,4".split(","))}
  component =  Component.first
  component.update(params)


params = {:supplier=> Supplier.get(1), :component_type => ComponentType.get(1), :nome => "ciao", :plant_types => PlantType.all(:id => "3,1".split(","))}
  component =  Component.first
  component.update(params)