[RUBY] Get the column name from the Model instance

I thought it would be nice if there was a key name list for display when creating the list screen.


1. Model creation

Create some model


class User < ApplicationRecord
  include Table #If you include it here, you can use it as an instance method

  attribute :name
  attribute :email
  attribute :login_id
  attribute :password


2. Create a method to get the column name from the Model instance


module Table
  extend ActiveSupport::Concern

  #Get column name (symbol) as an array
  def table_keys
    self.class.column_names.map(&:to_sym).reject { |column| %i[id created_at updated_at].include?(column) }

    #Click here if you want to get it as a character string
    # self.class.column_names.reject { |column| %w[id created_at updated_at].include?(column) }

  #Get column name
  def col_name(column_name)
  1. Get  ĽUser from @ useretc. withself.class`
  2. Get the column name list with column_names.map (&: to_sym) and convert it to a symbol
  3. reject { |column| %w[id created_at updated_at].include?(column) }Exclude unnecessary column names in

3. Display on the list screen


- if @users.present?
        - first_user = @users.first
        - first_user.table_keys.each do |key|
          = tag.td first_user.col_name(key)
      - @users.each do |user| 
          - user.table_keys.each do |key|
            = tag.td {|tag| tag.span user.send(key)}
- else
p No data

I was able to display it like this. (I use bootstrap) ![image.png](https://qiita-image-store.s3.ap-northeast-1.amazonaws.com/0/554638/22731714-2129-b0bd-89a1-b4aa9048e747.png)


This kind of screen is often used for devise and active_admin, but it seems that it can also be used when passing the validation key to the front side.

If you have any advice, please do not hesitate to contact us.

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