ios - 保存到核心数据“ALL 或 ANY 运算符的左侧必须是 NSArray 或 NSSet

Question

当我尝试将关系保存到核心数据时，它会在标题中抛出上述错误。我基本上是在创建一个消息传递应用程序，并附加了数据模型。当尝试保存到其他关系时，这也是在做同样的事情。我可以一次保存我所有的数据模型，还是应该一次保存一个，然后在模型及其常规属性保存后返回并添加关系。 ** Data Model Visual

    static func save(sender: UserCD, message: String) -> Conversation? {

    let convo: Conversation? = nil

    guard let appDelegate = UIApplication.shared.delegate as? AppDelegate else {
        return convo
    }

    if #available(iOS 10.0, *) {

        let context = appDelegate.persistentContainer.viewContext

        let now = Date()

        let messageEntity = NSEntityDescription.entity(forEntityName: "Message", in: context)
        let newMessage = NSManagedObject(entity: messageEntity!, insertInto: context) as! Message

        let conversationEntity = NSEntityDescription.entity(forEntityName: "Conversation", in: context)
        let newConvo = NSManagedObject(entity: conversationEntity!, insertInto: context) as! Conversation

        newMessage.setValue(UUID().uuidString, forKey: "messageId")
        newMessage.setValue(message, forKey: "text")
        newMessage.setValue(now, forKey: "timestamp")
        newMessage.setValue(sender, forKey: "sender")

        newConvo.setValue(UUID().uuidString, forKey: "conversationId")
        newConvo.setValue(now, forKey: "startDate")
        newConvo.setValue(now, forKey: "lastMessageDate")
        newConvo.addMessage(message: newMessage)

        sender.addMessage(message: newMessage)
        sender.addConversation(conversation: newConvo)

        do {
            try newMessage.managedObjectContext?.save()
            try sender.managedObjectContext?.save()
            try newConvo.managedObjectContext?.save()

            return newConvo

        } catch {
            let saveError = error as NSError
            print("Failed to save conversastion: \(saveError.debugDescription)")
        }
    }
    return convo
}

它在“newConvo.addMessage(message: newMessage)”行失败

    @NSManaged public var messages: Message?

func addMessage(message: Message) {
    let messages = self.mutableSetValue(forKey: "messages")
    messages.add(message)
}

Answer 1

错误信息

The left hand side for an ALL or ANY operator must be either an NSArray or an NSSet

很清楚:

• 您声明了 messages作为一对一关系Message .

• 方法的发送者addMessage必须是对多关系Set<Message>