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!
