在Rails中查找自连接列的值

Question

I'm pretty rusty working on Rails, so I apologize if this is a noob question.

I have a table called "Customer", which has a column called "parent_customer_id", which is a self-referential column looking at the id column in the same table

how do i design the model and view files (not clear on how to write the lookup code in the view) so that, in the view, i can show data in this format:

Customer Name: @customer_name (Parent Customer Name: @parent_customer_name)

Answer 1

So in your Customer model, you'll have

belongs_to :parent_customer, class: Customer
has_many :child_customers, class: Customer, 
         foreign_key: "parent_customer_id"

And in your view, you'll have something like this:

Customer Name: <%= @customer.name %> (Parent customer name: 
      <%= @customer.parent_customer.try "name" %>)

Use "try" so that Rails doesn't throw an exception if there's no parent customer.