What's the difference between belongs_to and has_one?

Question

What is the difference between a belongs_to and a has_one?

Reading the Ruby on Rails guide hasn\'t helped me.

Answer 1

One additional thing that i want to add is, Suppose we have following models association

class Author < ApplicationRecord has_many :books end

if we only write the above association then we can get all books of a particular author by,

@books = @author.books

But for a particular book we can't get the corresponding author by,

@author = @book.author

to make the above code work work we need to add association to Book model also, like this

class Book < ApplicationRecord
  belongs_to :author
end

This will add method 'author' to Book model.
For mode details see guides