nested_form and STI about nested_form HOT 3 CLOSED

What's the exception? You may need allow the mass-assignment of attachments.

And do you really need STI? For what you have, you may need a Polymorphic association instead of the STI (depending on how related the discussions and the posts really are).

Anyway, paste your exception, that'll make it easier to see what's going wrong.

from nested_form.

I'm not sure what I'm supposed to do.
I thought that because of the inheritance I should only modify _form if discussion. when i changed it the attachments weren't added.
then I added to discussion.rb
has_many :attachments, :dependent => :destroy accepts_nested_attributes_for :attachments, :reject_if => lambda { |a| a[:url].blank? }, :allow_destroy => true

but when showing a post I got :
The single-table inheritance mechanism failed to locate the subclass: 'Discussion'. This error is raised because the column 'type' is reserved for storing the class in case of inheritance. Please rename this column if you didn't intend it to be used for storing the inheritance class or overwrite Post.inheritance_column to use another column for that information.

Edit : I finally noticed the warning "WARNING: Can't mass-assign protected attributes: attachments_attributes"

Discussion and post should have the same data but different behavior.

from nested_form.

What's your database schema for the posts table? To use STI you'll need a type:string attribute. Then, if you're creating a Discussion, the type of that discussion should be discussion.

With that, you should be able to add the accepts_nested_attributes_for to the Post model.

About this Discussion and post should have the same data but different behavior.

I'm not sure, but I guess that if you have a _form partial under the app/views/discussions, rails will load that one instead of the posts/_form one.

But, if the behaviour is really different, I don't think the STI is the right approach. I would use Polymorphic Associations. That way you'll be able to have this:

Post has_many :attachments, :as => :holder
Discussion has_many :attachments, :as => :holder
Attachment belongs_to :holder, :polymorphic => true

And you'll be able to scale it easier without having non-related classes in the same table.

Hope this helps you... but if it doesn't, paste your Post database schema...

from nested_form.