Can't figure out why form won't save to database ruby on rails -

i trying save "product" aka pair of glasses database following data fields-- name, lens, frame, temple, accent, quantity, photo.

app/controllers/product_controller.rb

def create    @product = product.create(product_params)  end  # each pair of glasses has name, lens, frame, accent, quantity, , picture def product_params    params.require(:product).permit(:name, :lens_id, :frame_id, :temple_id, :accent_id, :quantity, :photo) end 

app/views/products/_form.html.erb

<div class="field">     ....     <%= f.label :quantity %>     <%= number_field_tag :quantity, nil, class: 'form-control', min: 1 </div>   

i can save record , saves database except quantity saves 'nil'. can go rails console, select record, , manually add quantity via console though... missing?

thanks in advance!

the error result of helper tag using :quantity. should using form builder helper number_field , not generic number_field_tag.

it should this:

<%= f.number_field :quantity, nil, class: 'form-control', min: 1 %> 

if isn't working you, perhaps due version of rails, can override type attribute on text_field , try:

<%= f.text_field :quantity, nil, class: 'form-control', type: :number, min: 1 %> 

---

if want know why, need understand how rails building post form data. using form builder form_for see of form fields follow convention object_class[attribute]. in example it'd make product[name], product[lens_id], etc...

by using number_field_tag created input name quantity need product[quantity] when call product.create(product_params) includes provided value.

your code producing params:

 {     product:      {      name: '...',      lens_id: 1    },    quantity: 1  } 

vs expected:

{   product:   {     name: '...',     lens_id: 1,     quantity: 1   } }