Question

I have products as an embedded document inside the category class as shown below:

require 'mongo_mapper'

class Category

include MongoMapper::Document

key :Name, String
key :NumberOfProducts, Integer
many :products

end

and here is the Product class:

require 'mongo_mapper'

class Product

include MongoMapper::EmbeddedDocument

  key :Name, String

end

I am using the following code to display the Products but it says no method “Name” found.

require 'rubygems'
require 'mongo'
require 'mongo_mapper'
require 'category'
require 'product'

include Mongo

MongoMapper.database = 'Northwind'

categories = Category.all()

categories.each{|category| puts category.Name

  unless category.Products.nil?

     category.Products.each{|product| puts product.Name}

  end


}

here is the error:

 undefined method `Name' for {"Name"=>"Amiga"}:BSON::OrderedHash (NoMethodError)

Answer 1

Well, first thing to try is that you have:

many :products

…but then you try to access it with category.Products.each

Definitely keep your naming consistent, and I’d recommend using ruby conventions (underscored, not camel cased, and certainly not capitalized camel case for non-classes).

So, maybe:

class Category
  include MongoMapper::Document
  key :name, String
  many :products
end

class Product
  include MongoMapper::EmbeddedDocument
  key :name, String
end


categories = Category.all
categories.each do |category|
  puts category.name
  category.products.each do |product|
    puts "  " + product.name
  end
end