Note belongs_to Company or Contact?

Rails
1

I’m wondering if anyone has suggestion on how to go about setting up a
Model that can belong to multiple tables (but only one of them).

For example, I have Companies and Contacts, both of whom can have Notes.
However, I’d really rather not duplicate everything so that I have
CompanyNotes and ContactNotes, so I’m wondering if there’s any way I can
do the following:

class Note < ActiveRecord::Base
belongs_to [ [ :company, { :through => :companies_notes } ], [
:contact, :{ through => :contacts_notes } ] ]
end

Or if there’s any suggestions as to a better way to go about doing this.

2

On Dec 22, 2007 7:32 PM, Philip S.
[email protected]
wrote:

belongs_to [ [ :company, { :through => :companies_notes } ], [
:contact, :{ through => :contacts_notes } ] ]
end

Or if there’s any suggestions as to a better way to go about doing this.

Check out polymorphic associations. Should do exactly what you’re
looking
for.

3

Note can belong to more than one model. For this u need polymorphic
association. Define notable model with polymorphic as true. Other
model that use has many declaration with :as notable in it

Sent from my iPhone

On Dec 22, 2007, at 4:32 PM, Philip S.
<[email protected]

4

Michael G. wrote:

On Dec 22, 2007 7:32 PM, Philip S.
[email protected]
wrote:

belongs_to [ [ :company, { :through => :companies_notes } ], [
:contact, :{ through => :contacts_notes } ] ]
end

Or if there’s any suggestions as to a better way to go about doing this.

Check out polymorphic associations. Should do exactly what you’re
looking
for.

Sweet, thanks!

5

On Dec 22, 2007, at 6:32 PM, Philip S. wrote:

I’m wondering if anyone has suggestion on how to go about setting up a
Model that can belong to multiple tables (but only one of them).

For example, I have Companies and Contacts, both of whom can have
Notes.
However, I’d really rather not duplicate everything

I have almost exactly that.

Here’s the migration:

class CreateNotes < ActiveRecord::Migration
def self.up
create_table :notes do |t|
t.column :notable_id, :integer #required
t.column :notable_type, :string #required
t.column :created_at, :datetime
t.column :processed_by, :string, :limit => 20
t.column :body, :text
t.column :title, :string, :limit => 50
t.column :department, :string, :limit => 30
end
end

The necessary columns are the id and type.

And the Note class

class Note < ActiveRecord::Base
belongs_to :notable, :polymorphic => true
end

And then for any class you want to have notes, just make it look like
this:

class Client < ActiveRecord::Base
has_many :notes, :as => :notable
end

And that’s it. Now you can simply write something like this:

 client = Client.find(1)  #for example
 note = Note.new
 note.title = "the title"
 note.body = "the body"
 note.department = 'some department'
 note.processed_by = current_user_name
 client.notes << note

And with that last line the note is magically associated with that
client, and is part of its notes array.
other than adding the has_many :notes, :as => :notable line, you
don’t have to do anything at all to the models you want notes for.

It’s been a while since I’ve even thought about this, but I don’t
think I’ve forgotten anything.
Hope this helps.

6

Philip S. wrote:

Is there no join table to tie the two together? Or is that all done
automagically somehow…

Cancel that! Found out how it works in the Agile Web Dev w/Rails book
:slight_smile: Thanks everyone!

7

Is there no join table to tie the two together? Or is that all done
automagically somehow…