class LineItem < ActiveRecord::Base
belongs_to :order
end
class Order < ActiveRecord::Base
has_many :line_items
end
my_line_item = LineItem.find(:zipcode => "12345")
Order.find_by_line_item(my_line_item) # doesn't work
Order.find_by_line_item_id (my_line_item) # does work
I was surprised by this, because it seems to force me to make reference
to the id field of the line item, rather than referring to the LineItem
as a class or type in the Order.findxxx statement.
Am I misunderstanding something or missing a trick?
class LineItem < ActiveRecord::Base
belongs_to :order
end
class Order < ActiveRecord::Base
has_many :line_items
end
my_line_item = LineItem.find(:zipcode => "12345")
Order.find_by_line_item(my_line_item) # doesn't work
Order.find_by_line_item_id (my_line_item) # does work
Probably not explaining this clearly enough (I blame the distillery
masters at Lagavulin), but:
find_by_line_item fails - my_line_item is an instance of the class (an
object) that does not have a 'line_item' attribute you indicated, it
*is* a LineItem
find_by_line_item_id works - rails infers the id attribute when you pass
an object (my_line_item), and in this case you've provided enough
information to tell rails which attribute to use...
I suppose you could mod the logic for find to include your syntax...
class LineItem < ActiveRecord::Base
belongs_to :order
end
class Order < ActiveRecord::Base
has_many :line_items
end
my_line_item = LineItem.find(:zipcode => "12345")
Order.find_by_line_item(my_line_item) # doesn't work
Order.find_by_line_item_id (my_line_item) # does work
Probably not explaining this clearly enough (I blame the distillery
masters at Lagavulin), but:
Wish I was there! Which of their Beer is available in the US?
find_by_line_item fails - my_line_item is an instance of the class (an
object) that does not have a 'line_item' attribute you indicated, it
*is* a LineItem
It kind of does, in that Order has_many :line_items, no? And so that's
an ActiveRecord method on Order called line_items?
By the way, my_order.find_by_line_item fails with "no such method", not
just by returning .
I wonder if my_order.find_by_line_items would work?
As I am sure you know the 'find_by*' methods are all dynamic. They are
based on the field/column name, not on the type of object the column
is supposed to reference (if any). AR will do the magic of finding the
ID value if you pass an object to the method but apparently it will
not be "magic enough" to let you remove the '_id' suffix from the
field/column name in your 'find_by*' method name. It would be nice if
the Rails guys made a little change so we could do what you wanted to
do here, though.
