Ruby on Rails - adding a self reference in ruby on rails- ruby on rails tutorial - rails guides - rails tutorial - ruby rails
A self reference can be useful to build a hierarchical tree. This can be achieved with add_reference in a migration.
class AddParentPages < ActiveRecord::Migration[5.0]
def change
add_reference :pages, :pages
end
end
Clicking "Copy Code" button will copy the code into the clipboard - memory. Please paste(Ctrl+V) it in your destination. The code will get pasted. Happy coding from Wikitechy - ruby on rails tutorial - rails guides - ruby rails - rubyonrails - learn ruby on rails - team
The foreign key column will be pages_id. If we want to decide about the foreign key column name, we have to create the column first and add the reference after.
class AddParentPages < ActiveRecord::Migration[5.0]
def change
add_column :pages, :parent_id, :integer, null: true, index: true
add_foreign_key :pages, :pages, column: :parent_id
end
end