mongoid字段不重复序列码生成方式

  field :code, type: String

  validates :code, uniqueness: { scope: :site,
    message: "核销码不能重复" }
  index code: 1

  before_create :gen_code

  private

  def gen_code
    self.code = (0..9).to_a.sample(10).join
    self.valid?
    if self.errors[:code].any?
      logger.debug "重复重新生成"
      gen_code
    end
  end