Question

Let’s assume I have two models.

class User < ActiveRecord::Base
  has_one :blog
end

class Blog < ActiveRecord::Base
  belongs_to :user

  validates_presence_of :user
  validates_uniqueness_of :user_id
end

Let’s assume I have one user with a blog. For some reason, let’s pretend I call create_blog for the same user (I know it should not be an option since the user already has a blog). If this blog doesn’t pass the validations, and it won’t, not only isn’t saved, but it deletes the previous blog the user has.

Why is this happening? Why the initial blog gets deleted? Is this behavior expected or is there something I missing?

Answer 1

By calling create_blog you’re telling Rails to discard the previous blog. There isn’t a way around this (that I am aware of) that doesn’t involve doing something like this:

blog = Blog.new(params[:blog])
if blog.valid?
  user.blog = blog
  user.save
end