polymorphism - rails polymorphic add using << -

polymorphism - rails polymorphic add using << -

my new rails 4.1 project has next polymorphic associations.

class order < activerecord::base has_many :line_items, as: :line_itemable end class lineitem < activerecord::base belongs_to :line_itemable, polymorphic: true end class shipment < activerecord::base has_many :line_items, as: :line_itemable end

i trying migrate old info have in seeds.rb file

neworder = order.create |order| ... end neworder.line_items << lineitem.create |li| ... end

the << has worked me in past. in old scheme didn't have shipments class had

class order < activerecord::base has_many :line_items end class lineitem < activerecord::base belongs_to :order end

and << worked. now, have been able create migration work using

neworder = order.create |order| ... end newlineitem = lineitem.create |li| ... end newlineitem.update_attribute(:line_itemable, neworder)

this not seem rails way things. doing wrong?

the problem in migration not utilize class app/models, 1 within migration. check via rails console what's in line_itemable_type column chosen lineitem. instead of order see yourmigrationname::order, explains everything.

in general approach right though - practice define code in migration if requires work. there 1 gotcha polymorphic association :) think there no 'best' way deal - 1 can set type manually (this have done), 1 can craft sql query manually (if need create lot of objects way go, shouldn't placed in migration imo). can illustration set type this:

newlineitem = lineitem.create |li| li.line_itemable_type = 'order' li.line_itemable_id = neworder.id # other stuff have end

polymorphism ruby-on-rails-4.1