Rails中validates及各种用法

Rails中validates及各种用法

       首先是不为空validates :name,presence:{message:'blank is not allowed'}

       唯一性：validates :name,uniqueness:{message:'already exist!',case_sensitive: false}#case_sensitive区分大小写

       长度：validates :name,length:{in: 6..20,message:'must in 6-20 byte'} 

        格式：validates :name,format:{with: /[a-z]/,message:'must contain at least one lower case character'} 

        范围：validates :country,inclusion:{in:['China','USA','Jpan','Mexico'],message:'must one of China USA Jpan Mexico '} 

        数字：validates :graduate,numericality:{allow_nil: true,greater_than: 1920,less_than_or_equal_to:Time.now.year}

validates :description,presence:true,if: :require_description_presence?

 def require_description_presence?

      self.can_send_mail

 end

 这个validates :description,presence: true只有在require_description_presence?方法返回true的时候才会起作用

validate :description_length_words

 def description_length_words

    unless self.description.blank? then

       num_words = self.description.split.length

       if num_words < 5 then

         self.errors.add(:description,'must be at least 5 words long')

       elsif num_words > 50 

          self.errors.add(:description,'must be at most 50 words long')

        end 

    end 

end