我有嵌套属性的问题，我有下一个实体：
class Experience < ActiveRecord::Base
has_many :roles, inverse_of: :experience
end
class Role < ActiveRecord::Base
belongs_to :experience, inverse_of: :roles
end
我有下一组参数：
params = {"end_date"=>"02/01/2012",
"city"=>"Buenos Aires",
"state"=>"",
"country"=>"",
"title"=>nil,
"company"=>"Restorando",
"current"=>nil,
"description"=>nil,
"roles_attributes"=>
[{"id"=>558, "title"=>"System Owner", "start_date"=>"03/01/2000", "end_date"=>"02/01/2001", "description"=>"<p>I did a bunch of stuff</p>", "current"=>false},
{"id"=>561, "title"=>"Test", "description"=>nil, "current"=>nil},
{"id"=>557, "title"=>"Full Stack Developerr", "start_date"=>"01/01/2011", "end_date"=>"02/01/2012", "description"=>"<p>Full Stack Developer description</p>", "current"=>false}],
"resumes_experiences_attributes"=>[{"id"=>384, "resume_id"=>809}, {"id"=>385, "resume_id"=>3199}]}
我想更新一个 Rails 模型。所以我执行：
@experience = Experience.find(some_id)
@experience.update_attributes(params)
这给我返回一个错误
ActiveRecord::RecordNotUnique：PG::UniqueViolation：错误：重复的键值违反了唯一约束“roles_pkey”
如果我看到 Rails 试图更新什么，我会看到下一条sql语句：
UPDATE“角色”SET“start_date”= $1，“end_date”= $2，“current”= …