We will first understand our use case:

We will start with generating a scaffold. The general format is to write the command followed by the name of model, fields, and datatype of each field shown as follows:

:~/curry-nation$ rails g scaffold recipe title:string  cooking_time:string difficulty_level:string food_type_id:integer food_preference_id:integer cuisine_id:integer ingredients:text procedure:text

This will create files that include model, controller, basic views, and skeleton tests.

We can now see what we have already created. In order to see what we have created so far, let's fire up our server and see what we just created by navigating to localhost:3000.

Now, as we can see, the category values that we added previously are blank textboxes in our form. We would need to create dropdowns for each one of them so that they are selected and sent to the db.

    <div class="form-group">
      <%= f.label :food_preference %><br>
      <%= f.select(:food_preference_id, options_from_collection_for_select(FoodPreference.all, :id, :name), {:prompt => 'Please Choose'}, :class => "form-control")  %>
    </div>
  
<div class="form-group">
      <%= f.label :food_type %><br>
      <%= f.select(:food_type_id, options_from_collection_for_select(FoodType.all, :id, :name), {:prompt => 'Please Choose'}, :class => "form-control")  %>
    </div>

    <div class="form-group">
      <%= f.label :cuisine %><br>
      <%= f.select(:cuisine_id, options_from_collection_for_select(Cuisine.all, :id, :name), {:prompt => 'Please Choose'}, :class => "form-control")  %>
    </div>

As you can see in the preceding code, we are able to populate the values in the select box from our database tables and pass the IDs to the recipe table of the database.

We will define an array in the recipe model and access it in the view. There is also another dropdown required for "level of difficulty" to be defined inside the recipe model. We can create a simple array with the names of difficulty levels as follows:

app/models/recipe.rb
DIFFICULTY=%w(Easy Medium Hard)

We can now call the level of difficulties directly inside our views and access the array values by calling it on the model name using Recipe::DIFFICULTY, shown as follows:

app/views/recipes/_form.html.erb
   <div class="form-group">
      <%= f.label :difficulty_level %><br>
      <%=f.select :difficulty_level, Recipe::DIFFICULTY,{} , :class => "form-control"%>
    </div>