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 -~----------~----~----~----~------~----~------~--~---
