在我edit的{{1}}行动中，我有这行代码：
employees_controller如果没有，则应添加空白#Employee#edit
69: if @employee.user.person.addresses.length == 0
70: @employee.user.person.addresses << Address.new
71: end
，以便它显示在我的编辑erb文件中。这样，如果没有与该员工关联的地址，则他们在编辑此记录时被迫添加一个。
这样的多态关联：Address和Person <- User <- Employee与Person有多对多的关系。该声明如下：
Address代码在#class Person
has_many :address_person_links, :dependent => :destroy
has_many :addresses,
:through => :address_person_links,
:uniq => true,
:validate => false, # I thought this would fix it but doesn't
:dependent => :destroy
的第70行失败：
employees_controller.rb请注意其调用/usr/lib/ruby/gems/1.8/gems/activerecord-2.3.5/lib/active_record/validations.rb:1090:in `save_without_dirty!'
/usr/lib/ruby/gems/1.8/gems/activerecord-2.3.5/lib/active_record/dirty.rb:87:in `save_without_transactions!'
/usr/lib/ruby/gems/1.8/gems/activerecord-2.3.5/lib/active_record/transactions.rb:200:in `save!'
/usr/lib/ruby/gems/1.8/gems/activerecord-2.3.5/lib/active_record/connection_adapters/abstract/database_statements.rb:136:in `transaction'
/usr/lib/ruby/gems/1.8/gems/activerecord-2.3.5/lib/active_record/transactions.rb:182:in `transaction'
/usr/lib/ruby/gems/1.8/gems/activerecord-2.3.5/lib/active_record/transactions.rb:200:in `save!'
/usr/lib/ruby/gems/1.8/gems/activerecord-2.3.5/lib/active_record/transactions.rb:208:in `rollback_active_record_state!'
/usr/lib/ruby/gems/1.8/gems/activerecord-2.3.5/lib/active_record/transactions.rb:200:in `save!'
/usr/lib/ruby/gems/1.8/gems/activerecord-2.3.5/lib/active_record/associations/has_many_through_association.rb:63:in `insert_record'
/usr/lib/ruby/gems/1.8/gems/activerecord-2.3.5/lib/active_record/associations/association_collection.rb:119:in `<<'
/usr/lib/ruby/gems/1.8/gems/activerecord-2.3.5/lib/active_record/associations/association_collection.rb:433:in `add_record_to_target_with_callbacks'
/usr/lib/ruby/gems/1.8/gems/activerecord-2.3.5/lib/active_record/associations/association_collection.rb:118:in `<<'
/usr/lib/ruby/gems/1.8/gems/activerecord-2.3.5/lib/active_record/associations/association_collection.rb:116:in `each'
/usr/lib/ruby/gems/1.8/gems/activerecord-2.3.5/lib/active_record/associations/association_collection.rb:116:in `<<'
/usr/lib/ruby/gems/1.8/gems/activerecord-2.3.5/lib/active_record/associations/association_collection.rb:141:in `transaction'
/usr/lib/ruby/gems/1.8/gems/activerecord-2.3.5/lib/active_record/connection_adapters/abstract/database_statements.rb:136:in `transaction'
/usr/lib/ruby/gems/1.8/gems/activerecord-2.3.5/lib/active_record/transactions.rb:182:in `transaction'
/usr/lib/ruby/gems/1.8/gems/activerecord-2.3.5/lib/active_record/associations/association_collection.rb:140:in `transaction'
/usr/lib/ruby/gems/1.8/gems/activerecord-2.3.5/lib/active_record/associations/association_collection.rb:115:in `<<'
/home/aaron/NetBeansProjects/onlinescheduler/app/controllers/employees_controller.rb:70:in `edit'
的方式？为什么要这样做？
答案 0 :(得分：1)
这种情况正在发生，因为无论何时将AR对象添加到关联数组，它都会保存对象并尝试将其id添加到关联表中（如果它是many_to_many）
您可以尝试以下
#Employee#edit
69: if @employee.user.person.addresses.length == 0
70: @employee.user.person.addresses = [Address.new]
71: end
此外，如果您使用accepts_nested_attributes_for执行此操作，则惯例是使用build方法
#Employee#edit
69: if @employee.user.person.addresses.length == 0
70: @employee.user.person.addresses.build
71: end
有关详细信息，请参阅http://ryandaigle.com/articles/2009/2/1/what-s-new-in-edge-rails-nested-attributes
答案 1 :(得分：1)
首先，为了语义清晰，我建议你检查如下：
if @employee.user.person.addresses.empty?
接下来，如果您检查日志，您将看到地址（以及相应的address_person_link）被“＆lt;＆lt;”添加到数据库中方法，这反过来调用验证，这就是你的保存失败的原因（因为新创建的地址不验证）。
您可以修改地址验证，以避免在新创建的记录中运行它们（例如当您刚将其添加到使用“＆lt;＆lt;”的人时。就像这样：
validates_presence_of :name, :unless => Proc.new{|a|a.new_record?}
你必须添加：除非阻止你在地址验证上的每一个。