# HABTM relationships in views **URL:** \ **Category:** rubyonrails-talk\ **Created:** [June 17, 2009, 12:55pm UTC](https://discuss.rubyonrails.org/t/habtm-relationships-in-views/43540 "2009-06-17T12:55:56Z")\ **Posts on this page:** 5\ **Page:** 1
**Author:** ![11175](https://avatars.discourse-cdn.com/v4/letter/1/8edcca/32.png) [@11175](https://discuss.rubyonrails.org/u/11175)\ **Post date:** [June 17, 2009, 12:55pm UTC](https://discuss.rubyonrails.org/t/habtm-relationships-in-views/43540/1 "2009-06-17T12:55:56Z")
Hi everyone. I'm currently working on a bodybuilding supplement Website which have 3 models : \* Stack : has\_and\_belongs\_to\_many :products \* Product : has\_and\_belongs\_to\_many :stacks has\_and\_belongs\_to\_many :ingredients \* Ingredient : has\_and\_belongs\_to\_many :products Now what I am trying to do is list all the ingredients for a Stack (using standard params[:id]). It seems that I cannot pass multiple product\_ids (but one id work fine!) to get the ingredients listing. Here's a partial code from my controller : === START ===   def stack     begin       @stack = Stack.find(params[:id])       render :template =\> "public/stack\_#{@lang}"     rescue ActiveRecord::RecordNotFound       logger.error("Attempt to access invalid stack #{params[:id]}")       flash[:notice] = "Désolé, cette formule est introuvable."       redirect\_to :action =\> :index     end   end === END === Any help would be appreciate and I can provide more information if my request isn't clear enought. I am using RAILS\_GEM\_VERSION = '1.2.6' Thanks Hugues ---
**Author:** ![Colin\_Law1](https://avatars.discourse-cdn.com/v4/letter/c/91b2a8/32.png) [@Colin\_Law1](https://discuss.rubyonrails.org/u/Colin_Law1)\ **Post date:** [June 17, 2009, 1:06pm UTC](https://discuss.rubyonrails.org/t/habtm-relationships-in-views/43540/2 "2009-06-17T13:06:17Z")
@stack.products will give you an array of products then for each product, product.ingredients will give you an array of ingredients. Colin ---
**Author:** ![Colin\_Law1](https://avatars.discourse-cdn.com/v4/letter/c/91b2a8/32.png) [@Colin\_Law1](https://discuss.rubyonrails.org/u/Colin_Law1)\ **Post date:** [June 17, 2009, 4:41pm UTC](https://discuss.rubyonrails.org/t/habtm-relationships-in-views/43540/3 "2009-06-17T16:41:27Z")
product.ingredients is an array, you could reference product.ingredients[0].name or you could iterate the array using product.ingredients.each. Another useful construct is product.ingredients.map(&:name) which will give you an array of ingredient names. In all of this don't forget to watch out for a product with no ingredients (product.ingredients is nil in this case) which can give you run-time errors if you have not caught them. The same applies to stack.products. I wonder whether it would be useful for you to run through some basic Ruby tutorials to get a bit more grounding on the basics of Ruby. Good Luck Colin ---
**Author:** ![Bill\_Walton1](https://avatars.discourse-cdn.com/v4/letter/b/ba8739/32.png) [@Bill\_Walton1](https://discuss.rubyonrails.org/u/Bill_Walton1)\ **Post date:** [June 17, 2009, 5:06pm UTC](https://discuss.rubyonrails.org/t/habtm-relationships-in-views/43540/4 "2009-06-17T17:06:29Z")
> product.ingredients is an array, you could reference > In all of this don't forget to watch out for a product with no ingredients (product.ingredients is nil in this case) I'm sure you meant to say that product.ingredients is an empty array > I wonder whether it would be useful for you to run through some basic Ruby tutorials to get a bit more grounding on the basics of Ruby. Excellent advice, put very nicely. Best regards, Bill ---
**Author:** ![11175](https://avatars.discourse-cdn.com/v4/letter/1/8edcca/32.png) [@11175](https://discuss.rubyonrails.org/u/11175)\ **Post date:** [June 17, 2009, 5:24pm UTC](https://discuss.rubyonrails.org/t/habtm-relationships-in-views/43540/5 "2009-06-17T17:24:14Z")
Colin Law wrote: