验证嵌入文档的存在？

Question

我想确认在保存活动时至少输入了一个选项。选项是嵌入式mongoid文档。我怎么能这样做？

class Event

  include Mongoid::Document

  field :name, type: String
  field :description, type: String
  field :date, type: Date

  embeds_many :invitees, cascade_callbacks: true
  embeds_many :participants, cascade_callbacks: true
  embeds_many :comments, cascade_callbacks: true
  embeds_many :options, cascade_callbacks: true

  has_one :owner, :class_name => "User"

  validates :name, :date, :presence => true

  accepts_nested_attributes_for :options, autosave: true, allow_destroy: true
  accepts_nested_attributes_for :participants, autosave: true, allow_destroy: true
  accepts_nested_attributes_for :comments, autosave: true, allow_destroy: true
  accepts_nested_attributes_for :invitees, autosave: true, allow_destroy: true
  accepts_nested_attributes_for :owner, autosave: true, allow_destroy: true

end

Answer 1

您可以使用自定义验证程序执行此操作。

validate :has_at_least_one_option

def has_at_least_one_option
    if options.empty?
        errors[:base] << "Please choose at least one option"
    end
end

出现错误将导致对save的调用返回false并且无法保存模型。