Question

找不到轻松完成此操作的最佳方法我想针对以下问题提出数据库模型。

有一个Deal表，其中有一个关联的帐户表。每个帐户都可以有多个联系人。现在，一笔交易需要分配一个主要联系人，该主要联系人必须是相关帐户的多个联系人中的一个。如何确保主要联系人是其中一个帐户联系人。

Deal Table
  account_id
  primary_contact_id

Account Table
  name and other params

Contact Table
  account_id
  phone, email etc.

EG。我目前使用的课程

class Deal < ActiveRecord::Base
  belongs_to :account
  belongs_to :contact
end

class Account < ActiveRecord::Base
  has_many :contacts
  has_many :deals
end

class Contact < ActiveRecord::Base
  belongs_to :account
  has_many :deals
end

我可以在交易模型或控制器中添加验证，以确保添加的联系人是其帐户联系人之一。但如何照顾以下情况：

从帐户中删除联系人应确保将交易表的相应contact_id设置为nil
删除与交易相关联的帐户应确保该交易表的contact_id无效
更新帐户关联应确保交易的contact_id无效。

Answer 1

class Deal

  validate :contact_is_among_the_contacts_in_associated_account

  private

  def contact_is_among_the_contacts_in_associated_account
    errors.add(:contact_id, "Your error message") unless contact.in?(account.contacts)
  end

end

Answer 2

可能你可以使用模型回调，例如：

class Deal < ActiveRecord::Base
  belongs_to :account
  belongs_to :contact

  before_update :nullify_contact_association, :if => lambda{|i| i.account_id_changed?}

  private
  # Nullify contact_id of the deal if it's account association was changed
  def nullify_contact_association
    self.contact_id = nil
  end
end

class Account < ActiveRecord::Base
  has_many :contacts
  has_many :deals

  before_destroy :nullify_dependencies

  private

  #Deleting an account associated with a deal should
  #make sure that contact_id of that deal table is nullified
  def nullify_dependencies
    self.deals.update_all(:contact_id => nil) if deal.present?
  end
end

class Contact < ActiveRecord::Base
  belongs_to :account
  has_many :deals

  before_destroy :nullify_dependencies

  private

  #Deleting a contact from an account should make sure
  #that corresponding contact_id of the deal table is set to nil
  def nullify_dependencies
    self.deals.update_all(:contact_id => nil) if account.present?
  end
end

如何向rails模型添加验证，这取决于另一个模型

2 个答案: