1 comment system for multiple models

Rails
1

Hi all,

I have a commenting system I use on different models (posts, reports,
events) meaning that I have some difficulties using depend => destroy
and counter cache.

I now use a sub_id in my comment indicating whether the comment
belongs to a post, event or report eg:
Events table
id | owner_id | category_id | text
0 1 post …
1 1 event …
2 2 report …
3 2 post …

Where the owner_id is the id own the post, event or report.

This approach makes it hard to use either counter cache or depend =>
destroy since it will only look at the owner_id. If a user deletes
post 1 it will also delete the comments of both event 1 and report 1.

Someone has a better approach to using 1 comment system for multiple
models or can I overwrite counter cache and depend destoy to make use
of scoping?

All help is greatly appreciated.

Stijn

2

What you want to use here are polymorphic associations.
They work mostly like what you have done, using two
columns, one for the id, the other for the type.
commentable_id
commentable_type
in your case.

Then you could define associations like
has_many :comments, :as => :commentable, :dependent => :destroy

and Rails would be able to handle al the sub tasks as
it does with common associations.

read the details here:

since it’s a bit too complex to explain it here