circular relationship - habtm

So I have 2 models: Picture and Comment.

Pictures have many Comments, but I'd like for users to be able to post
Pictures in Comments, so Comments will have one Picture (possibly).
This creates a kind of circular relationship it looks like, and the
only way I could think of to implement this is with
has_and_belongs_to_many. Am I right, or is there a better way to do
this?

Hi --

So I have 2 models: Picture and Comment.

Pictures have many Comments, but I'd like for users to be able to post
Pictures in Comments, so Comments will have one Picture (possibly).
This creates a kind of circular relationship it looks like, and the
only way I could think of to implement this is with
has_and_belongs_to_many. Am I right, or is there a better way to do
this?

You could just do some judicious association naming -- something like:

class Picture < AR::Base
   has_many :comments
   belongs_to :comment, :foreign_key => "illustration_id"
end

class Comment < AR::Base
   belongs_to :picture
   has_one :illustration, :class_name => "Picture"
end

That way, comment.picture = some_picture would always mean that this
comment belongs to that picture, while comment.illustration =
some_picture would mean that a given picture belonged to this comment.

Or... you could decide that the comment also belongs to the picture it
contains, with a distinct foreign key and so forth, though that might
feel a bit inside out.

David