Active Record Associations - best way to find all items assosciated with a specific company

I have the following associations in my models:

item.rb belongs_to :manufacturer, :class_name => "Company" belongs_to :distributor, :class_name => "Company"

company.rb has_many :items

My question: what is the best way to find all of the items belonging to a specific company?

If I call Company.items I (understandably) get the error message: ActiveRecord::StatementInvalid: SQLite3::SQLException: no such column: items.company_id: SELECT "items".* FROM "items" WHERE ("items".company_id = ... )

Should I write a little helper method that does what I want, something along the lines of:

Item.where("items.manufacturer_id LIKE :record OR items.distributor_id LIKE :record",{:record =>})

or is there a better way to do this through associations?

Would be grateful for any advice.

If you have a company in @company (for example) then that companies items are @company.items. Similarly for an @item its company is

I think you might benefit from working through some tutorials. is good and free to use online.

I say that assuming that you have already worked through the Rails Guides.


On second thoughts perhaps *I* would benefit from reading your question more carefully.

You have a problem with your associations, for company you need to specify two associations for the two associations to item. I need to just check exactly what you need to do....


Trying again.

I have the following associations in my models:

item.rb belongs_to :manufacturer, :class_name => "Company"

I am not sure if it is necessary but you might need :foreign_key => "manufacturer_id" here. I put it in to remind me what the field is called anyway.

belongs_to :distributor, :class_name => "Company"

Same here

company.rb has_many :items

Here you need two associations has_many :manufacturer_items, :class_name => "Item" has_many :distributor_items, :class_name => "Item" where manufacturer_items is a name you can choose yourself.

Then for a particular company @company the items are @company.manufacturer_items and @company.distributor_items.


Many thanks for your quick help Colin. That's a nice solution to the problem and it's also good to find out what the best practice is. Jim

I am not sure I am confident that this is *best* practice, but it works for me. Others more experienced may well have alternative suggestions.


Although this does indeed work well, I would still be interested to hear any other suggestions ...