Confused About Money-Rails Gem

Question

I'm working my way through basic calculator app ...

Trying to integrate money-gem in it but confused ...

This is the current schema (as you can see, it doesn't have any columns ending with _cents ... and very confused if the _cents part is needed ...

Current Schema

ActiveRecord::Schema.define(version: 20170301051956) do

  # These are extensions that must be enabled in order to support this database
  enable_extension "plpgsql"

  create_table "tippies", force: :cascade do |t|
    t.float    "tip",        null: false
    t.decimal  "cost",       null: false
    t.datetime "created_at", null: false
    t.datetime "updated_at", null: false
  end

end

In the model, I added monetize :tip & monetize: cost ...

Do I need to modify the tip and cost columns in the schema, ie, remake it to be integer, and add the post _cents part?

Current Model

class Tippy < ApplicationRecord

    validates :tip, presence: true
    validates :cost, presence: true

    monetize :tip
    monetize :cost


    TIP_CHOICES = { "10%" => ".10", "20%" => ".20", "30%" => ".30", "40%" => ".40", "50%" => ".50", 
                    "60%" => ".60", "70%" => ".70", "80%" => ".80", "90%" => ".90" }


    def calculation_of_total_cost 
        cost + (tip * cost)
    end

end

When I try to go to my homepage (it's set to the new page), I get this error:

ArgumentError in TippiesController#new

Unable to infer the name of the monetizable attribute for 'tip'. Expected amount column postfix is '_cents'. Use :as option to explicitly specify the name or change the amount column postfix in the initializer.

It refers specifically to the monetize :tip in the model ...

Show.html.erb

<br/><br/>
<h1 class="text-center">Your Total Cost</h1>
<br/><br />


<table class="table table-striped">
    <tr>
        <td>
            Cost of Your Meal:
        </td>
        <td>
            <%= humanized_money_with_symbol @tippy.cost) %>
        </td>
    </tr>
    <tr>
        <td>
            Tip You Picked:
        </td>
        <td>
             <%= number_to_percentage(@tippy.tip * 100, format: "%n%", precision: 0) %>
        </td>
    </tr>
    <tr>
        <td>
            The Total Cost:
        </td>
        <td>
            <%= number_to_currency(@tippy.calculation_of_total_cost) %>
        </td>
    </tr>
</table>

new.html.erb

<br /><br />
<h1 class="text-center">Calculate Your Tip!</h1>

<%= render 'form', tippy: @tippy %>

_form.html.erb

<%= form_for(tippy, :html => {'class' => "form-horizontal"}) do |f| %>
  <% if tippy.errors.any? %>
    <div id="error_explanation">
      <h2><%= pluralize(tippy.errors.count, "error") %> prohibited this tippy from being saved:</h2>

      <ul>
      <% tippy.errors.full_messages.each do |message| %>
        <li><%= message %></li>
      <% end %>
      </ul>
    </div>
  <% end %>


  <div class="field form-group">
    <%= f.label :cost_of_your_meal, class: "control-label" %>
    <%= f.text_field :cost, class: "form-control" %>
  </div>

  <div class="field form-group">
    <%= f.label :pick_your_tip, class: "control-label" %>
    <%= f.select(:tip, Tippy::TIP_CHOICES, class: "form-control")  %>
  </div>


  <div class="actions">
    <%= f.submit class: "btn btn-primary btn-lg btn-block" %>
  </div>
<% end %>

How do I make this work? Please let me know if more information is needed. Thank you

Answer 1

I was confused about this too at first. The gem wants you to use the first column it provides which is the name of the column with _cents added to it. So your model should have this in it

monetize :tip_cents
monetize :cost_cents

That column, and a column with _currency is created by the gem.