軌領域驗證如果

Question

我有一個領域模型Product：

name price product_type_id:integer size:string page_quantity:integer. 

如何可以使Product模式create動作此驗證工作？

- if product_type.id == "1" 
    validates :size, presence: true 
    validates :page_quantity, presence:false 
- else 
    validates :size, presence: false 
    validates :page_quantity, presence:true 
end 

Answer 1

validates :size, presence: true, if: Proc.new { |p| p.product_type_id == "1" } 
    validates :page_quantity, presence:false, if: Proc.new { |p| p.product_type_id == "1" } 
    validates :size, presence: false, unless: Proc.new { |p| p.product_type_id == "1" } 
    validates :page_quantity, presence:true, unless: Proc.new { |p| p.product_type_id == "1" } 
end