如何在某些情况下仍然允许属性为零的同时验证数值和包含? [英] How to validate numericality and inclusion while still allowing attribute to be nil in some cases?

问题描述

在 Rails 应用程序中，我在模型上有几个整数属性.

In a Rails app I have several integer attributes on a model.

用户应该能够创建记录并将这些属性留空.

A user should be able to create a record and leave these attributes blank.

或者，如果用户为这些属性输入值，则应验证它们的数量和在一定范围内.

Or, if the user enters values for these attributes, they should be validated for numericality and within a certain range.

在模型中我有这样的东西

In the model I have something like this

validates_presence_of :name    
validates_numericality_of :a, :only_integer => true, :message => "can only be whole number."
validates_inclusion_of :a, :in => 1..999, :message => "can only be between 1 and 999."

如果我现在用最少的必需属性进行测试:

If I now test with the minimum required attributes to save:

factory :model do
  sequence(:name) { |n| "model#{n}" }
end

it "should save with minium attributes" do
  @model = FactoryGirl.build(:model)
  @model.save.should == false
end

我明白了

Validation failed: a can only be whole number., a can only be between 1 and 999.

如何仅在为 :a 指定值时验证数字和包含性，同时在某些情况下仍允许 :a 为零?

How can I validate numericality and inclusion only if a value is given for :a, while still allowing :a to be nil in some cases?

谢谢

推荐答案

您可以添加 :allow_nil =>对您的 validates_numericality_of 为真.

You can add an :allow_nil => true to your validates_numericality_of.

validates_numericality_of :a, :only_integer => true, :allow_nil => true, 
    :message => "can only be whole number."

如果您只想使用一种验证，也可以使用 greater_than_or_equal_to 和 less_than_or_equal_to 选项:

You can also use greater_than_or_equal_to and less_than_or_equal_to options if you just want to use one validation:

validates_numericality_of :a, :only_integer => true, :allow_nil => true, 
    :greater_than_or_equal_to => 1,
    :less_than_or_equal_to => 999,
    :message => "can only be whole number between 1 and 999."

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