Rails Migration Question

Can anyone help me in this:

Given the following database migration:

    class DefineDatabase < ActiveRecord::Migration

      def self.up         create_table "products" do |t|           t.column "name", :string           t.column "price_converted", :integer # NOTE: we shouldn't store monetary values as floats to avoid rounding errors         end

        create_table "categories" do |t|           t.column "name", :string         end

        create_table "categories_products" do |t|           t.column "product_id", :integer, :null=>false           t.column "category_id", :integer, :null=>false           t.column "display_order", :integer, :default=>0, :null=>false         end       end

      def self.down         drop_table "products"         drop_table "categories"         drop_table "categories_products"       end

    end

I need to implement model classes named Category and Product so that the following code example generates the expected output:

    cat1 = Category.new(:name=>'Books')     cat1.save     p1 = cat1.products.create(:name=>'My first book', :price=>10.99 )     puts p1.price_converted # should be the price in cents, that is x 100 and rounded up to next whole number     >> 1099     p2 = cat1.products.create(:name=>'My second book', :price=>20.95 )     puts p2.price_converted     >> 2095

    cat1.set_display_order(p1, 1) # this should set the 'display_order' column associated with the product p1 to 1

    prod_array = cat1.products.find(:all, :order=>'display_order, price')     puts prod_array[0].name     >> My second book     puts prod_array[1].name

instead of just looking for someone that is willing to implement your models and methods, why don't you just give it a try first and ask if you encounter any problems?

start by defining the relations between models (has_many, belongs_to, ...). add callbacks (after_save :convert_price) and methods (def convert_price). all along write some tests to see if your code is working correctly.

if you're stuck somewhere, come back and ask for help.