Rails将值传递给关联的模型

Question

I'm trying to make a association that automatically get the name of the object. for exemple

**User has one Brand**

User Table:
id
Name

=================

**Belongs to User**

Brand Table:

id
user_id
user_name

So i would like to know how to pass the user name to the brand table, thank's

Answer 1

Just define a method:

class Brand < ActiveRecord::Base

  belongs_to :user

  def user_name
    user.name
  end

end

Answer 2

b = Brand.first
name = b.user.name

Answer 3

Its not really necessary to have that extra user name column in your database.

You can simply do brand.user.name to get the user's name.

so if your view has an instance of @brand you would simply do @brand.user.name

Otherwise do as meagar said.

Answer 4

You can use the delegate method for this. For example

model

class Brand < ActiveRecord::Base
  belongs_to :user
  delegate :name, to: :user, prefix: true
end

usage

brand = Brand.find(params[:id])
puts brand.user_name