balance promotion settings

app/models/balance_promotion.rb

@@ -2,7 +2,15 @@ class BalancePromotion < ActiveRecord::Base
     has_paper_trail
     self.table_name = "balance_promotions"
     validates :begin_time,:end_time,:name, presence: true
-
+    validate :product_validation
+    def product_validation
+      if self.send_prod1 > 0
+        prd1 = Product.where("id = ?", self.send_prod1).first
+        if prd1.blank?
+          self.errors.add(:send_prod1,"赠品1不存在，请重新填写。")
+        end
+      end
+    end
     def send_prodcut1
       prd1 = Product.where("id = ?", self.send_prod1).first
       if !prd1.blank?