Ancestry:从作用域跳过元素

Question

使用宝石祖先。

如何从Category:：ActiveRecordRelation中跳过self元素或需要使用范围？

= simple_form_for @category do |f|
  = f.input :parent_id, collection: Category.roots 

类似于：

= f.input :parent_id, collection: Category.roots.except(@category)

Answer 1

= f.input :parent_id, collection: Category.roots.where("id <> ?", @category.id)

或通过范围

类别.rb

scope :except, lambda{ |category| where("id <> ?", category.id) }

然后

= f.input :parent_id, collection: Category.roots.except(@category)