Hey everyone... I'm just getting my feet wet with relational databases using RoR models. The software I'm putting together relies on car parts. Originally I had the database set up as follows create_table :parts do |t| t.column :year, :string t.column :make, :string t.column :model, :string . . . end However, I now realize it's much better to do it using relationships instead. Unfortunately, I'm not too familiar with this method and have been reading up on it for a few hours. I just want to post what I think I'm supposed to be doing here and hopefully get a little feedback as to whether I'm approaching this correctly before I start programming it into my application... class Year < ActiveRecord::Base has_many :makes end class Make < ActiveRecord::Base belongs_to :year has_many :models, :through => something_else end class Model < ActiveRecord::Base belongs_to :make has_many :parts, :through => something end class Part < ActiveRecord::Base belongs_to :model end However, I guess what is confusing me is that if I try to set it up this way, if I enter a part for a 1999 Jeep Cherokee, how would I link the part (say with part_id = 1337) to 1999, Jeep, and Cherokee? Would I need to refine my setup here and link the part directly to the year, make, and model by adding belongs_to and has_many or would I simply add a column for make_id, model_id, year_id to my "create_table :parts" method? ie: create_table :parts do |t| t.column :year_id t.column :make_id t.model :model_id end The other thing confusing me is the ":through => something" stuff. In one example I see can see creating a friendship table that links two users, but I'm not sure how I would apply it in this case or if it is even smart to do it this way... Any help would be appreciated. Thanks!
on 2009-04-24 09:47
on 2009-04-24 10:50
Hey Bernhard, take a look first into this. There is a really good explanation, hope you come along with this. http://guides.rubyonrails.org/association_basics.html Rafael On 24 Apr., 07:47, Bradley H. <firstname.lastname@example.org>
on 2009-04-24 22:54
I think I'm making some progress here, but what I'm wondering about now is whether or not my full-text search using acts_as_ferret will still work. Right now, in the old database setup I have, the text search will find everything in the parts table. However, lets say I link part1 with model1 through a model_id (or part_id), will searching parts for "model1" yield a result?
on 2009-04-25 00:49
Okay... Here is what I have... Let me know if I should make any refinements... http://farm4.static.flickr.com/3316/3471892268_47a... class Year < ActiveRecord::Base has_many :makes has_many :models, :through => :make has_many :parts, :through => :model end class Make < ActiveRecord::Base belongs_to :year has_many :models has_many :parts, :through => :model end class Model < ActiveRecord::Base belongs_to :make belongs_to :year has_many :parts end class Part < ActiveRecord::Base belongs_to :model belongs_to :make belongs_to :year end
on 2009-04-25 09:48
Ideally I'd like a part to have a year_id, make_id, and model_id. I'd like a model to have a single make_id but have the option of belonging to several years (aka: Corvette could have years 1952 thru 2009). The make would belong to several years and have several makes (ie. Chevy from 1911-Present, and models like Corvette, Malibu, Camaro, etc...). I don't know why this is confusing me so much, but any help would be appreciated.