HABTM relationships in views

Rails
1

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

2

2009/6/17 Hugues B. [email protected]:

  • Ingredient :
    Â def stack
    === END ===
    @stack.products will give you an array of products then for each
    product, product.ingredients will give you an array of ingredients.

Colin

3

Colin L. wrote:

2009/6/17 Hugues B. [email protected]:

  • Ingredient :
    Â def stack
    === END ===
    @stack.products will give you an array of products then for each
    product, product.ingredients will give you an array of ingredients.

Colin

Thank you Colin, it seems to work since “#” character appear for each
ingredient of a product. Now I must figure out how I get the
ingredient’s name. Can you give me an exemple, since
product.ingredients.name doesn’t work?
Regards,
Hugues

4

2009/6/17 Hugues B. [email protected]:

Thank you Colin, it seems to work since “#” character appear for each
ingredient of a product. Now I must figure out how I get the
ingredient’s name. Can you give me an exemple, since
product.ingredients.name doesn’t work?

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

5

Colin L. wrote:

2009/6/17 Hugues B. [email protected]:

Thank you Colin, it seems to work since “#” character appear for each
ingredient of a product. Now I must figure out how I get the
ingredient’s name. Can you give me an exemple, since
product.ingredients.name doesn’t work?

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

Thank you Colin. I managed to get it right with your advice using

product.ingredients.each do |ingredient|

and then using

ingredient.name

I will do some Arrays and Hashes tutorials right away since I think I’m
gonna need to manipulate data that way sooner or later.

6

On Wed, 2009-06-17 at 17:41 +0100, Colin L. wrote:

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