Rails：如何设置活动记录关联？

Question

I am relatively new to rails and doing the simplest thing: Associate users and posts. I read this , but what more than this do I need to do to make it work (or is this the only thing)?:

class User < ActiveRecord::Base
  has_many :posts, :dependent => :destroy
end

class Post < ActiveRecord::Base
  belongs_to :user
end

Update: I can't make it work. When I make a post with a signed in user, I get false when I do @user.posts.any? in the console. My code:

post.rb

class Post < ActiveRecord::Base
  attr_accessible :title, :user_id
  belongs_to :user
  before_create :default_values

user.rb (I use devise)

class User < ActiveRecord::Base
  devise :database_authenticatable, :registerable,
         :recoverable, :rememberable, :trackable, :validatable

  attr_accessible :email, :password, :password_confirmation, :remember_me
  has_many :posts, dependent: :destroy
end

20130320162700_create_posts.rb

class CreatePosts < ActiveRecord::Migration
  def change
    create_table :posts do |t|
      t.string :title
      t.integer :user_id

      t.timestamps
    end
  end
end

Answer 1

You should make sure to include User's id in the migration that creates the posts table. In your migration file (in the db/migrate folder you will find a file named like 20130325105934_create_posts.rb)

Inside the file you will find the migration code. Along the other declared attributes add

class CreatePosts < ActiveRecord::Migration
  def change
    create_table :posts do |t|
     ...... 
     t.integer :user_id
     ......
  end

end

It should be enough to make things roll :-)

Inside your code then you can create a new user as

@user = User.new(:login => "my_user", .....)

and then add posts with one of these two ways (there are others two).

post = Post.new(:title => "something", :text => "more of something", :user_id = @user.id)

or

   post = Post.new(:title => "something", :text => "more of something")
   @user.posts << post