Question

I have a price field for a product in a catalog. Sometimes the admin user is putting a comma when dealing with thousands (ex: $10,000) and sometimes he is just doing $6000. While I would like to simply tell him to do it one way or the other, I would also like to solve the issue programmatically.

The #show action responsible is here:

def show
       @category = Category.find_by_url_name(params[:category_id])
       @brand = Brand.find(params[:id])

       @search = Product.find(:all, :conditions => ['brand_id = ? and  category_id = ?', @brand.id, @category.id],
          :order=> params[:order] || 'price DESC')
       @products = @search.paginate(:page => params[:page], :per_page => 12 )

    @meta_title = "#{@brand.name}"
    respond_to do |format|
      format.html # show.html.erb
      format.xml  { render :xml => @brand }
    end
  end

I also have a sort_options helper in my application helper that is providing the ordering options to the site user:

def product_sort_options
    options_for_select([
      ['', nil],
      ['Newest to Oldest', 'descend_by_date'],
      ['Oldest to Newest', 'ascend_by_date'],
      ['Price: Highest to Lowest', 'descend_by_price'],
      ['Price: Lowest to Highest', 'ascend_by_price'],
      ['Name', 'ascend_by_name']
    ])
  end

any ideas?

Answer 1

To make it a full answer – price should not be a string. The fact that you have 300 products now is not a big deal.

Make a migration:

rails generate migration decimalise

Then edit it (db/migrate/*decimalise.rb), and write something like this:

class Decimalise < ActiveRecord::Migration                                                                                                                                                                                       
  def up
    connection = ActiveRecord::Base.connection()
    # kill the weird chars in the string field
    connection.execute("UPDATE products SET price = REPLACE(REPLACE(price, ',', ''), '$', '')")

    # convert the string column into a decimal one
    change_table :products do |t|
      # adjust for your use case - this gives you values up to 9999999.99
      # if you need more, increase the 10
      t.column :price, :decimal, :precision => 10, :scale => 2
    end
  end

  def down
    change_table :products do |t|
      t.column :price, :string, :limit => 10
    end
  end
end

then finally, run

rake db:migrate

(untested, you will probably need to tweak. also, back up your DB before any tinkering – I’ll not be responsible for any data loss you suffer)

EDIT One thing I forgot: how to print it out.

<%= number_to_currency @product.price %>

should give you something like $1,999.99 for a price of 1999.99.