Question

我需要一个控制器来传递符合特定范围的父母的子记录。我希望这个范围在父记录上。

class Parent < ApplicationRecord
  has_many :children

  scope :not_blue, -> { where(blue:false) }
  scope :blue,     -> { where(blue:true) }

  # Subjective, may change in the future
  scope :funny,  -> { where('funny_scale>=?',5) }

  scope :genies,     -> { blue.funny }
end

class Child < ApplicationRecord
 belongs_to :parent, required: true
end

class ChildrenController < ApplicationController
  def index
    # Yeah, this breaks horribly (and should), but you get my gist
    @children_of_genies = Parent.genies.children
  end
end

我知道答案可能正在盯着我，但谷歌搜索的正确组合让我望而却步。

Answer 1

范围返回ActiveRecord_Relation，为children的每个成员获取collect：

@children_of_genies = Parent.genies.collect { |p| p.children }

Answer 2

如果您希望自己的解决方案仍然是ActiveRecord::Associations::CollectionProxy尝试Children.where(parent_id: Parent.genies.ids)，那么您可以将其转变为范围。

scope: children_of_genies, -> { where(parent_id: Parent.genies.ids)

如何在Rails 5

2 个答案: