I don't think a delegate would work. Okay, just to recap on the database structure:
products | id | name | price | | 1 | a | 2.50 | | 2 | b | 1.50 | suppliers | id | name | | 1 | s_a | | 2 | s_b | products_suppliers | id | supplier_id | product_id | supplier_type | | 1 | 1 | 1 | "vendor" | | 2 | 1 | 2 | "manufacturer"| Firstly, I don't think that 'products_suppliers' is a good name since this form is only a requirement for HABTM to work. It should be more descriptive of the relationship, but your call. Okay, so I believe that you want to do something like this: p = Product.first p.vendors # => [#< Supplier id: 1, name: "s_a">, #<Supplier id: 2, name: "s_b">] p.manufacturer # => #< Supplier id: 1, name: "s_a"> You might want to try this: class Product < ActiveRecord::Base has_many :products_suppliers has_many suppliers, :through => products_suppliers named_scope :vendors, :conditions => ["supplier_type = ?", "vendor"] named_scope :manufacturer, :conditions => ["supplier_type = ?", "manufacturer"] end This does not restrict the manufacturer to a one-to-many relationship, so you will have to ensure that each product will have only one manufacturer (you can do this pretty easily with some validations). On Apr 8, 11:14 am, Matt Jones <al2o...@gmail.com> wrote: > On Apr 7, 1:28 pm, Marcelo de Moraes Serpa <celose...@gmail.com> > wrote: > > > > > > > So let's take this code > > > p = Product.find(1) > > > What I need is a specific products_suppliers related to specific combo of > > (supplier_id,product_id) keys, so I can get the supplier_type data related > > to this product+supplier. However, I the has_many relationship in Supplier > > reaturns all the products_suppliers that has supplier_id == the id of this > > supplier -- To get the specific products_supplier I would also need the id > > of the product that owns this supplier, but I can't get it. So, the first > > thing I though was something like has_one :through. That's why I said, a > > has_one relationship through a link table. The thing is, I need the > > product_id that owns this supplier from the supplier model. I might as well > > just leave AR and do some raw SQL, or maybe use sql :select statemente in > > the association to fetch the type from the link table into the association. > > > Does that make sense? > > Maybe this is too obvious, but given the example above, couldn't you > just use: > > p.products_suppliers.find_by_supplier_id(some_supplier_id) > > That will give you the supplier that you're looking for. > > BTW, I'd recommend a different name for the supplier_type column - > that pattern (same as the foreign key, with _type instead of _id) is > the Rails convention for single table inheritance, which is NOT what > you're looking for here. It shouldn't cause a problem, but the AR > association code is known to sometimes get really weird indigestion > from that situation... > > Hope this helps, > > --Matt Jones --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to rubyonrails-talk@googlegroups.com To unsubscribe from this group, send email to rubyonrails-talk+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en -~----------~----~----~----~------~----~------~--~---
