Ruby on rails active record associations

问题

I need 2 models for my store:

1. Shoe
2. ShoeSize

According to my concept - one shoe can have several sizes (one model of shoes can be 34,35,36,37 size).

What types of associations should I use? What database table fileds do I need to create to support these associations?

Here is an example of the models in use:

Shoe.find(1).shoe_sizes => 34,35,36

ShoeSize(2).shoes => #Shoe1, #Shoe2, #Shoe5

回答1:

You should use a has_and_belongs_to_many relationship.

class Shoe
  has_and_belongs_to_many :shoe_sizes
end

class ShoeSize
  has_and_belongs_to_many :shoes
end

This is because a Shoe can have many shoe sizes, and likewise one shoe size is available in for different shoes.

来源：https://stackoverflow.com/questions/8771551/ruby-on-rails-active-record-associations