How to get information from child table

Question

I have a Users model with has_many :comments Each comment records the current_user to the commenter column.

How can I call @commenter.username in my view and show the commenter's username?

Currently in comments_controller using: @commenter = User.find("2") will pull the correct information. I would like to use something along the lines of: @commenter = User.find_by_id(:commenter)

Answer 1

From the comments, it sounds like you have this Comment model:

class Comment < ActiveRecord::Base
  belongs_to :user
end

The comment model represents comments on a user's page , where the user model is defined as:

class User < ActiveRecord::Base
  has_many :comments
end

There is also a commenter column on the comments table to store the user who posted the comment (on the other user's page).

First, I would recommend using commenter_id for this column rather than commenter , since this is the convention for storing ids of any kind.

Assuming that you have a commenter_id column on the comments table, you would then define a second relationship as follows:

class Comment < ActiveRecord::Base
  belongs_to :user
  belongs_to :commenter, class_name: "User", foreign_key: :commenter_id
end

The commenter relationship defines the user who wrote the comment, rather than the user whose page the comment is on .

For the other side of this relationship, update your User model:

class User < ActiveRecord::Base
  has_many :comments
  has_many :page_comments, class_name: "Comment", foreign_key: :commenter_id
end

Here, page_comments defines the comments this user has posted on other users' pages.

Then if you have a @comment , you can get the commenter's name with simply:

@comment.commenter.name

As long as you setup your column names and models correctly, dealing with getting information like this should be very simple.