One to many relationship: Couldn't find Ofertum with 'id'=3 - ruby-on-rails

Question

I have problem to link to show file
http://localhost:3000/sigs/3
I got this error
ActiveRecord::RecordNotFound in SigsController#show
Couldn't find Ofertum with 'id'=3
Please help me. Here is my codes
I have two models: One for offers and one for signs
Each offer have signs and each sign have one offer
In sig model
belongs_to :ofertum
in ofertum model
has_many :sigs
in routes
resources :oferta
resources :sigs
in sigs controller
class SigsController < ApplicationController
def new
#ofertum = Ofertum.find(params[:id])
#sig = #ofertum.sigs.build
end
def create
#ofertum = Ofertum.find(params[:id])
#sig = #ofertum.sigs.build(sig_params)
if #sig.save
redirect_to sigs_path(:id => #ofertum.id)
end
end
def destroy
#ofertum = Ofertum.find(params[:id])
#sigs=#ofertum.sigs
if #sigs.destroy
redirect_to root_path
end
end
def show
#ofertum = Ofertum.find(params[:id])
#sigs=#ofertum.sigs
end
def edit
end
def update
end
def index
end
def destroy
end
private
def sig_params
sig_params = params.require(:sig).permit([:name,:comment,:description,:price,:image])
end
end
In oferta index.html.erb
<% #oferta.each do |o| %>
<ul class="cat">
<li class="pull-left"><h2><%= link_to o.offer,o %></h2><br><h4><%= o.description %></h4>
<div class="main">
<% if o.sigs.exists? %>
<div id="myBtnContainer">
<% for item in o.sigs %>
<button class="btn active" onclick="filterSelection('<%= item.name %>')"><%= item.name%><%= link_to item.description,item %><br></button>
<% end %>
</div>
<div class="row">
<% for item in o.sigs %>
<div class="column <%= item.name %>">
<div class="content">
<%= image_tag item.image.url(), style: "width:100%"%>
<h4><br><%= item.name %></h4>
<p><%= item.comment %></p>
</div>
</div>
<% end %><br><br>
</div>
<% end %>
</div>
<% end %>
In the database
class AddNameToSig < ActiveRecord::Migration[5.2]
def change
add_column :sigs, :name, :string
add_column :sigs, :comment, :string
add_column :sigs, :description, :text
add_column :sigs, :price, :string
end
end
in sigs show.html.erb
<%= #sig.name %>
<div class="container">
<%= link_to #sig, class: "btn tf-btn btn-default", method: :delete, data: { confirm: "Are you sure you want to delete this sign?" } do %>Delete <% end %>
</div>

Answer 1

The param in the path /sigs/3 is about a sig, not an ofertum. So you might do this way
def show
sig = Sig.find(params[:id])
#sigs = sig.ofertum.sigs
end
or
def show
ofertum = Sig.find(params[:id]).ofertum
#sigs = ofertum.sigs
end
and yes, if you need even the ofertum in the view
def show
#ofertum = Sig.find(params[:id]).ofertum
#sigs = #ofertum.sigs
end