1.不为空:validates :name,:presence=>{:message=>'blank is not allowed'}html
2.惟一性：validates :name,:uniqueness:{:message=>'already exist!',:case_sensitive=>false}#case_sensitive区分大小写less
3.长度：validates :name,length:{in: 6..20,:message=>'must in 6-20 byte'}ui
最小长度:minimum=>5，最大长度:maximum=>100spa
4.格式：validates :name,:format:{with: /[a-z]/,message=>'must contain at least one lower case character'}orm
5.范围：validates :country,:inclusion:{in:['China','USA','Jpan','Mexico'],:message=>'must one of China USA Jpan Mexico '}htm
6.数字：validates :graduate,:numericality:{:allow_nil=>true,greater_than: 1920,less_than_or_equal_to:Time.now.year}blog
7.validates :description,presence:true,if: :require_description_presence?ip
def require_description_presence?get
self.can_send_mailit
end
这个validates :description,presence: true只有在require_description_presence?方法返回true的时候才会起做用
8.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