Question

I am trying to search my postgresql db in rails. I followed the Railscasts #111 Advanced Search tutorial and it is working for the name and category of my items column in plain text. However, I want to set a min/max price on my search as well which is where I come into my problem. In my db my price is stored as a string in the format “AU $49.95”. Can I convert this into a float on the fly in my scoped search? If so how? If not, what should I do?

Here is the code:

search.rb

class Search < ActiveRecord::Base
  attr_accessible :keywords, :catagory, :minimum_price, :maximum_price

    def items
      @items ||= find_items
    end

    private

    def find_items
      scope = Item.scoped({})
      scope = scope.scoped :conditions => ["to_tsvector('english', items.name) @@ plainto_tsquery(?)", "%#{keywords}%"] unless keywords.blank?
      scope = scope.scoped :conditions => ["items.price >= ?", "AU \$#{minimum_price.to_s}"] unless minimum_price.blank?
      # scope = scope.scoped :conditions => ["items.price <= ?", "AU \$#{maximum_price.to_s}"] unless maximum_price.blank?
      scope = scope.scoped :conditions => ["to_tsvector('english', items.catagory) @@ ?", catagory] unless catagory.blank?
      scope
    end

end

searches_controller.rb

class SearchesController < ApplicationController
  def new
    @search = Search.new
  end

  def create
    @search = Search.new(params[:search])
    if @search.save
      redirect_to @search, :notice => "Successfully created search."
    else
      render :action => 'new'
    end
  end

  def show
    @search = Search.find(params[:id])
  end
end

Thanks for reading this far!

Answer 1

Use the data type numeric or money for exact numerical calculation without rounding errors – and sorting as a number (not as text).
Converting string literal to numeric should not be a performance problem at all.