Rails controller saving from different table

Question

I'm new to rails to bear with me.

This concerns two of my models: Product and Manufacturer.

When creating a new product the user can select which manufacturer the product belongs to from a drop down list. The problem is that I can't get this manufacturer to save. I know I have to add some code to the controller and I've tried various things but to no avail.

Here's the view:

<h1>New Product</h1>

<%= form_for(@product) do |f| %>
<div>
    <%= f.label :name, 'Name' %>
    <%= f.text_field :name %>
</div>

<div>
    <%= f.label :market_price, 'Market Price' %>
    <%= f.text_field :market_price %>
</div>
<div>
    <%= f.label :sell_price, 'Sell Price' %>
    <%= f.text_field :market_price %>
</div>
<div>
    <%= f.label :stock_level, 'Stock Level' %>
    <%= f.text_field :stock_level %>
</div>
<div>
    <%= f.label :manufacturer, 'Manufacturer' %>
    <%= f.collection_select(:manufacturer, Manufacturer.all, :id, :name, prompt: true) %>
</div>
<div>
    <%= f.label :location, 'Location' %>
    <%= f.collection_select(:location, Product.all, :id, :location, prompt: true) %>
    </div>
<br> </br>
<div>
        <%= f.submit "Create Product" %>
</div>

And here's part of the controller:

def create
  @product = Product.new(params[:product].permit(:name, :market_price, :sell_price, :stock_level, :location))
  @product.save
  flash[:notice] = 'Product Created'
  redirect_to @product
end
end

After hours of trying several nesting methods, I still can't get this to work. Surely it's very common to save fields from various models on one page???

In addition abbot567's answer which is very useful, I think you also need to permit the manufacturer id in the controller, which is a nested object. More info: stackoverflow.com/questions/18436741/… — jyrkim
– jyrkim, Commented May 9, 2015 at 10:05

abbott567 · Accepted Answer · 2015-05-09 09:59:14Z

1

You would usually nest your routes, so that products were within manufacturer:

resources :manufacturer do
    resources :products
end

Then your form would be a form for an array:

form_for([@manufacturer, @product]) do |f|
    f.hidden_field :manufacturer_id, value: @manufacturer.id

This allows you to pass in the ID of both the manufacturer and the product.

Now in your controller you can use something like the following, provided the associations are set up, such as product belongs_to :manufacturer and manufacturer has_many :products

@manufacturer = find(params[:manufacturer_id])
@product = @manufacturer.products.create()

answered May 9, 2015 at 9:59

abbott567

8626 silver badges19 bronze badges

Sign up to request clarification or add additional context in comments.

7 Comments

sevenseacat Over a year ago

while this is interesting, it's not at all relevant to the question at hand.

abbott567 Over a year ago

@sevenseacat it isn't? I apologise if this is the case. Perhaps I misunderstood the question?

Arkane55 Over a year ago

@abbott567 where do the last two lines of code go in the controller? Thanks!!

abbott567 Over a year ago

@Arkane55 they would go in the create action. In the question you posed, you had Product.new then Product.save, the two lines would replace this. This will look up the manufacturer, and then create and save a product linked to that manufacturer

abbott567 Over a year ago

also, as @jyrkim mentions in the comments above, you would possibly need to add :manufacturer_id to your permitted parameters

|

sevenseacat · Accepted Answer · 2015-05-09 10:15:52Z

0

In your form, you need to have a field for manufacturer_id, not manufacturer. You would change f.collection_select(:manufacturer to be f.collection_select(:manufacturer_id.

Then, in your controller, you need to add manufacturer_id to the list of parameters you are permitting in your permit method call. So it would be Product.new(params[:product].permit(:name, :market_price, :sell_price, :stock_level, :location, :manufacturer_id)).

answered May 9, 2015 at 10:15

sevenseacat

25.1k6 gold badges66 silver badges90 bronze badges

5 Comments

Arkane55 Over a year ago

I tried this method and it didn't work. Besides I don't see the difference between having manufacturer_id and name in the form, can you explain?

sevenseacat Over a year ago

What "didn't work"? You use manufacturer_id because that's the name of the field in your database, as it is an association with the Manufacturer model.

rohitpaulk Over a year ago

@Arkane55 - If this doesn't work, it's probably an issue with the way you've set up your models (has_one/has_many and belongs_to relationships)

Arkane55 Over a year ago

@sevenseacat So my Manufacturer model has 3 fields: id (auto generated), name and manufacturer_id (which I added after reading your post). How are name and manufacturer_id any different? They are similar fields. The error which I got was undefined method 'manufacturer_id'. @rohitpaulk the associations are set up fine: manufacturer has_many products and product belongs_to manufacturer

sevenseacat Over a year ago

Ah no, I presumed you have a manufacturer_id field on your Product model, given you said a product belongs to a manufacturer.

Collectives™ on Stack Overflow

Rails controller saving from different table

2 Answers 2

7 Comments

5 Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

7 Comments

5 Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related