Ruby on rails 创建rails上的rails控制台回滚

我有一个名为conversation的按钮，当用户单击它时，它会在数据库中创建一个作为记录的对话。问题是如果有3个用户userA、userB和userC

若userB点击对话按钮发送信息给userA，它将创建对话记录。但是，如果userC单击对话按钮发送消息userA，记录将不会保存，我将得到回滚

对话控制器：

class ConversationsController < ApplicationController
before_action :authenticate_user!

def index
  @conversations = Conversation.involving(current_user)
end

def create
  if Conversation.between(params[:sender_id], params[:recipient_id]).present?
  @conversation = Conversation.between(params[:sender_id], params[:recipient_id]).first
else
  @conversation = Conversation.create(conversation_params)
end

redirect_to conversation_messages_path(@conversation) 

end

private
  def conversation_params
    params.permit(:sender_id, :recipient_id)
  end
end

对话模式：

class Conversation < ApplicationRecord
  belongs_to :sender, foreign_key: :sender_id, class_name: "User"
  belongs_to :recipient, foreign_key: :recipient_id, class_name: "User"

 has_many :messages, dependent: :destroy
 validates_uniqueness_of :sender_id, :recipient_id

 scope :involving, -> (user) {
   where("conversations.sender_id = ? OR conversations.recipient_id = ?", user.id, user.id)
 }

scope :between, -> (user_A, user_B) {
  where("(conversations.sender_id = ? AND conversations.recipient_id = ?) OR (conversations.sender_id = ? AND conversations.recipient_id = ?)", user_A, user_B, user_B, user_A)
 }
end

---

您的唯一性应该是有范围的，否则您只需要设置两个独立的唯一性，并且（在您的示例中）发送方在整个数据库中只能有一个会话，接收方在整个数据库中只能有一个会话

正确的方法是

validates :sender_id, uniqueness: { scope: :recipient_id, message: "there is already a converation between these people" }

范围限定的

表示此收件人只能有一条与此发件人相关的记录

  validates_uniqueness_of :sender_id, :recipient_id

validates :sender_id, uniqueness: { scope: :recipient_id, message: "there is already a converation between these people" }