Question

I want to create a model to store comments related to articles. I have a strong feeling that in the future I will want comments on other objects in the app too. How do I design commenting in my app so that it will be forward compatible with adding new parent objects. I want to avoid a scenario where have multiple controllers/models for each object to comment relationship.

After watching Ryan Bates screen cast on Nested Resource I have a firm grasp on how tp nest a resource under a single parent. How do I achieve this under 2 or more parent resources?

Thanks!

Answer 1

For “forward compatible with adding new parent objects” part of the question:

You could use Polymorphic Associations. Here’s a nice example. Also see RailsCast #154.

An example of how it could look like for you:

The comments table columns’ could be like this:

id:integer
commentable_type:string
commentable_id:integer
comment_text:string

Some Sample records:

1,'Article',12,'My first comment' #comment on an Article model
2,'Question',12,'My first comment' #comment on a Question model
3,'Question',15,'My first comment' #comment on a Question model