验证是否存在一个或另一个字段（XOR）

Question

如何验证一个字段或另一个字段的存在，但不是两个字段或至少一个字段？

Answer 1

如果条件语句添加到numericality验证，像这样你的代码将工作：

class Transaction < ActiveRecord::Base 
    validates_presence_of :date 
    validates_presence_of :name 

    validates_numericality_of :charge, allow_nil: true 
    validates_numericality_of :payment, allow_nil: true 


    validate :charge_xor_payment 

    private 

    def charge_xor_payment 
     unless charge.blank?^payment.blank? 
     errors.add(:base, "Specify a charge or a payment, not both") 
     end 
    end 

end 

Answer 2

钢轨3.

class Transaction < ActiveRecord::Base 
    validates_presence_of :date 
    validates_presence_of :name 

    validates_numericality_of :charge, :unless => proc{|obj| obj.charge.blank?} 
    validates_numericality_of :payment, :unless => proc{|obj| obj.payment.blank?} 


    validate :charge_xor_payment 

    private 

    def charge_xor_payment 
     if !(charge.blank?^payment.blank?) 
     errors[:base] << "Specify a charge or a payment, not both" 
     end 
    end 
end 

Answer 3

validate :father_or_mother 

#Father姓或母姓例强制

def father_or_mother 
     if father_last_name == "Last Name" or father_last_name.blank? 
      errors.add(:father_last_name, "cant blank") 
      errors.add(:mother_last_name, "cant blank") 
     end 
end 

试试上面的简单例子。

Answer 4

class Transaction < ActiveRecord::Base 
    validates_presence_of :date 
    validates_presence_of :name 

    validates_numericality_of :charge, allow_nil: true 
    validates_numericality_of :payment, allow_nil: true 


    validate :charge_xor_payment 

    private 

    def charge_xor_payment 
     if [charge, payment].compact.count != 1 
     errors.add(:base, "Specify a charge or a payment, not both") 
     end 
    end 

end 

，你甚至可以用3个或多个值做到这一点：

if [month_day, week_day, hour].compact.count != 1 

Answer 5

我认为这是Rails的更地道3+：

如：用于验证的user_name或email一个是目前：

validates :user_name, presence: true, unless: ->(user){user.email.present?} 
validates :email, presence: true, unless: ->(user){user.user_name.present?} 

Answer 6

我把我的答案在下面这个问题。在这个例子中:description和:keywords是字段，其中这一个不能为空：

validate :some_was_present 

    belongs_to :seo_customable, polymorphic: true 

    def some_was_present 
    desc = description.blank? 
    errors.add(desc ? :description : :keywords, t('errors.messages.blank')) if desc && keywords.blank? 
    end