Please see wiki for discussion.
The DM polymorphic gem mimics AR style polymorphism. It has been decided that DM will not follow this path, since it
really isn't very nice on the DB and there are other ways, that do not require DBA to cry to achieve the same result.
That being said this is still useful for those ppl wishing to convert rails apps over.
One Massive Caveat is that using this you will get n+1 calls to the db atm if you do Comments#commentable for example. It needs a proxy object if anyone cares to write one.
This is highly experimental software, use it at your own risk.
==== Example Usage.
class Comment
include DataMapper::Resource
is :polymorphic, :commentable
property :id, Integer, :serial => true
property :text, String
end
class Post
include DataMapper::Resource
property :id, Integer, :serial => true
property :name, String
has n, :comments, :polymorphically => :commentable
end
class Article
include DataMapper::Resource
property :id, Integer, :serial => true
property :name, String
has n, :comments, :polymorphically => :commentable
end
This will then provide the following methods
Comment#commentable
Comment#post
Comment#article
Post#comments
Article#comments
What is needed is a
Comment.commentables or something method so there is a nice proxy to avoid having all the loading issues.