validates_uniqueness_of传递为零或空白（无allow_nil和allow_blank）

Question

的ActiveRecord 的唯一性验证器具有选项以跳过验证如果值是零或空白。即使我设置两个参数为true（默认行为），我可以验证之前点击创建零和空白的一个记录。我使用默认SQLITE3数据库的sqlite3-红宝石（1.2.5）。

编辑澄清：我得到预期的结果，如果我添加validates_presence_of示范。我认为validates_uniqueness_of的默认行为将使这是多余的。

<强>测试用例：

rails validation_test
cd validation_test/
script/generate Model Thing identification:string
rake db:migrate

应用程序/模型/ thing.rb的含量：

class Thing < ActiveRecord::Base
  validates_uniqueness_of :identification
end

Rails的控制台：

script/console 
Loading development environment (Rails 2.3.4)
>> Thing.create!
=> #<Thing id: 1, identification: nil, created_at: "2009-09-26 01:49:32", updated_at: "2009-09-26 01:49:32">
>> Thing.create! :identification => ""
=> #<Thing id: 2, identification: "", created_at: "2009-09-26 01:49:42", updated_at: "2009-09-26 01:49:42">
>> Thing.create! :identification => ""
ActiveRecord::RecordInvalid: Validation failed: Identification has already been taken
    from /usr/lib/ruby/gems/1.8/gems/activerecord-2.3.4/lib/active_record/validations.rb:1090:in `save_without_dirty!'
    from /usr/lib/ruby/gems/1.8/gems/activerecord-2.3.4/lib/active_record/dirty.rb:87:in `save_without_transactions!'
    from /usr/lib/ruby/gems/1.8/gems/activerecord-2.3.4/lib/active_record/transactions.rb:200:in `save!'
    from /usr/lib/ruby/gems/1.8/gems/activerecord-2.3.4/lib/active_record/connection_adapters/abstract/database_statements.rb:136:in `transaction'
    from /usr/lib/ruby/gems/1.8/gems/activerecord-2.3.4/lib/active_record/transactions.rb:182:in `transaction'
    from /usr/lib/ruby/gems/1.8/gems/activerecord-2.3.4/lib/active_record/transactions.rb:200:in `save!'
    from /usr/lib/ruby/gems/1.8/gems/activerecord-2.3.4/lib/active_record/transactions.rb:208:in `rollback_active_record_state!'
    from /usr/lib/ruby/gems/1.8/gems/activerecord-2.3.4/lib/active_record/transactions.rb:200:in `save!'
    from /usr/lib/ruby/gems/1.8/gems/activerecord-2.3.4/lib/active_record/validations.rb:1059:in `create!'
    from (irb):3
>> Thing.count
=> 2

为什么前两个创作通过？

由于

Answer 1

您是误会了默认的行为。从的文档：

:allow_nil - If set to true, skips this validation if the attribute is nil (default is false).
:allow_blank - If set to true, skips this validation if the attribute is blank (default is false).

设置这两个为真，我看到使用Rails 2.3.4以下行为。

class Thing < ActiveRecord::Base
  validates_uniqueness_of :identification, :allow_blank => true, :allow_nil => true
end

>> Thing.create! :identification => ""
=> #<Thing id: 6, identification: "", created_at: "2009-09-26 03:09:48", updated_at: "2009-09-26 03:09:48">
>> Thing.create! :identification => ""
=> #<Thing id: 7, identification: "", created_at: "2009-09-26 03:09:49", updated_at: "2009-09-26 03:09:49">
>> Thing.create! :identification => nil
=> #<Thing id: 8, identification: nil, created_at: "2009-09-26 03:09:52", updated_at: "2009-09-26 03:09:52">
>> Thing.create! :identification => nil
=> #<Thing id: 9, identification: nil, created_at: "2009-09-26 03:09:53", updated_at: "2009-09-26 03:09:53">

编辑：解决您的澄清 添加validates_presence_of将是你想要做什么是正确的。这不是多余的，因为它是检查一个完全不同的错误情况。它也有它自己的错误消息，这将是对用户很重要的。

class Thing < ActiveRecord::Base
  validates_uniqueness_of :identification, :allow_nil => true, :allow_blank => true
  validates_presence_of :identification
end