Question

对于父级父级的嵌套属性，Rails中的作用域唯一性验证存在问题。

背景

我有一个带有3个型号的rails 4应用程序：

#app/models/account.rb
class Account < ActiveRecord::Base
  has_many :contacts, dependent: :destroy
end

#app/models/contact.rb
class Contact < ActiveRecord::Base
  belongs_to :account
  has_many :email_addresses, dependent: :destroy, validate: :true, inverse_of: :contact
  accepts_nested_attributes_for :email_addresses,allow_destroy: true
  validates :email_addresses, presence: true
end

#app/models/email_address.rb
class EmailAddress  < ActiveRecord::Base
  belongs_to :contact, inverse_of: :email_addresses

  validates :label, presence: true
  validates :contact, presence: true
  validates :email, uniqueness: true, presence: true
  validates_email_format_of :email
end

问题

我想制作一个范围，以确保模型EmailAddress 的属性：电子邮件在帐户级别是唯一的（帐户是联系人的父级，本身就是EmailAddress的父级。

根据http://guides.rubyonrails.org/active_record_validations.html的建议，我尝试了：

 class EmailAddress  < ActiveRecord::Base
  belongs_to :contact, inverse_of: :email_addresses

  validates :label, presence: true
  validates :contact, presence: true
  validates :email, presence: true, uniqueness: { scope: :account, 
                    message: "This contact email is already taken" }
  validates_email_format_of :email
 end

这会引发错误＆＃34;列email_addresses.account不存在＆＃34; 我该怎么办？

谢谢你的帮助！

Answer 1

下面描述了在性能方面更好的选择。经过测试，效果很好。

<强>为什么吗

当许多电子邮件受到威胁时，映射电子邮件会占用大量资源，因此最好直接使用数据库执行范围。

如何？

在EmailAddress模型中兑现account_id并执行before验证方法。

1）创建迁移：

change_table :email_addresses do |t|
  t.references :account, index: true
end
add_index :email_addresses, [:account_id, :email], unique: true

2）迁移

3）更新EmailAddress模型

#app/models/email_address.rb

class EmailAddress < ActiveRecord::Base
  belongs_to :contact, inverse_of: :email_addresses
  belongs_to :account

  validates :label, presence: true
  validates :contact, presence: true
  validates_email_format_of :email
  validates_uniqueness_of :email, allow_blank: false, scope: :account

  before_validation do
    self.account = contact.account if contact
  end

end

Answer 2

我将提供一种可能的解决方案。未经测试，但应该可以使用自定义验证和额外关联。

在Account模型中：

has_many :email_addresses, through: :contacts

在EmailAddress模型中：

validate :uniqueness_of_mail

private
def uniqueness_of_mail
    account = contact.account
    if email in account.email_addresses.map(&:email)
        errors.add(email, 'Contact already has this email address')
        false
    else
        true
    end
end

Rails - 验证嵌套属性唯一性与父级的范围父级

2 个答案: