Hmm, maybe I'm complicating things. Maybe a delegate to the Product class (to get the product_id) would solve this... hmm, I will try that and let you guys know. Well, amazing how the fact of writing to the mailing list helps to find the solution by yourself :)
Thanks! Marcelo. On Tue, Apr 7, 2009 at 12:28 PM, Marcelo de Moraes Serpa < celose...@gmail.com> wrote: > Hello Jaryl, thanks for the reply, > > habtm is equivalent to has_many :through. just that the join table is not > an entity by itself, this I know :) > > So, I will try to explain through an example: > > Let's say we have a products table: > > | id | name | price | > | 1 | a | 2.50 | > | 2 | b | 1.50 | > > A suppliers table > > | id | name | > | 1 | s_a | > | 2 | s_b | > > So the idea is: A product may be supplied by many different suppliers. So, > indeed, it is a has_and_belongs_to_many relationship. The thing is, the > relationship by itself defines the type of the supplier (if it's either a > vendor or a manufacturer), since we have: > > products_suppliers table: > | id | supplier_id | product_id | supplier_type | > | 1 | 1 | 1 | "vendor" | > | 2 | 1 | 2 | "manufacturer"| > > So, in tis case, supplier s_a is a "vendor" of product a and a > "manufacturer" of product b. > > Product < ActiveRecord::Base > has_many :products_suppliers > has_many :suppliers, :through => :products_suppliers > end > > Supplier < ActiveRecord::Base > has_many :products_suppliers > has_many :products, :through => :products_suppliers > end > > ProductsSupplier < ActiveRecord::Base > belongs_to :product > belongs_to :supplier > end > > > 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? > > Thanks, > > Marcelo. > > > > > On Mon, Apr 6, 2009 at 9:47 PM, Jaryl Sim <quantum.crus...@gmail.com>wrote: > >> >> I couldn't really get your question, but I think that what you are >> trying to do here is to create a many to many relationship. >> >> Rails actually provides the has_and_belongs_to_many association for >> this very purpose, which should help you with what you are asking (I >> think). >> >> >> http://guides.rubyonrails.org/association_basics.html#choosing-between-has-many-through-and-has-and-belongs-to-many >> >> On Apr 7, 6:01 am, Marcelo de Moraes Serpa <celose...@gmail.com> >> wrote: >> > Actually the question would be better put this way: >> > >> > Having a has_one association via a link table (in this case >> > products_supplier). >> > >> > Thanks. >> > >> > On Mon, Apr 6, 2009 at 3:41 PM, Marcelo de Moraes Serpa < >> celose...@gmail.com >> > >> > > wrote: >> > > Let's say we have the following models: >> > >> > > Product < ActiveRecord::Base >> > > has_many :products_suppliers >> > > has_many :suppliers, :through => :products_supplier >> > >> > > Supplier < ActiveRecord::Base >> > > has_many :products_suppliers >> > > has_many :products, :through => :products_supplier >> > >> > > ProductsSupplier < ActiveRecord::Base >> > > belongs_to :supplier >> > > belongs_to :product >> > > end >> > >> > > Let' say we have this data in the products_suppliers table: >> > >> > > | supplier_id | product_id | >> > > | 1 | 2 | >> > > | 1 | 1 | >> > > | 2 | 2 | >> > > | 2 | 1 | >> > >> > > So when I do this: >> > >> > > @suppliers = Product.find(1).suppliers, it will return an array with >> the >> > > suppliers with id 1 and 2. >> > >> > > Let's say I do this: >> > >> > > @supplier = @suppliers[0] #Which is the supplier with id = 1, the one >> > > fetched from the (supplier_id = 1, product_id = 2) record in the >> > > products_suppliers table. Ok, now I got a single instance of a >> supplier. >> > > **What I want is to get the product_id it was associated with in the >> > > products_suppliers table.** (product_id = 2), might be missing >> something >> > > simple, but I can't seem to find a way to do that. >> > >> > > Any help appreciated! >> > >> > > Thanks, >> > >> > > Marcelo. >> >> >> > --~--~---------~--~----~------------~-------~--~----~ 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 -~----------~----~----~----~------~----~------~--~---
