如何保护领域中的重复记录插入

Question

我曾经在领域数据库中插入远程通知数据.但是,问题是,我发送的每个通知content-available = 1都意味着每次通知都来自didReceiveRemoteNotifications工作,并且当用户点击或不通知时保存静默通知.所以,如果我的应用程序在后台,将有两个记录插入.

第一个条件是当应用程序处于后台时发出通知,didReceiveRemoteNotification因为content-available = 1并且插入一条记录而被调用.

因此,第二个条件是如果用户在通知中心内点击通知,该方法didReceiveRemoteNotification再次工作并插入相同的记录.因此,重复问题.

func application(application: UIApplication, didReceiveRemoteNotification userInfo: [NSObject : AnyObject], fetchCompletionHandler handler: (UIBackgroundFetchResult) -> Void) {
    if let aps = userInfo["aps"] as? NSDictionary{
        if let alert = aps["alert"] as? NSDictionary{
            if let mbody = alert["body"] as? String{
                print("Message Body : \(body)")
                body = mbody
            }
            if let mtitle = alert["title"] as? String{
                print("Message Title : \(title)")
                title = mtitle
            }
        }
    }

    let newNotification = NotificationList()
    newNotification.title = title
    newNotification.body = body
    oneSignalHelper.insertOneSignalNotification(newNotification)
    NSNotificationCenter.defaultCenter().postNotificationName("refreshNotification", object: nil)

    handler(UIBackgroundFetchResult.NewData)

}

这是我的领域代码

func insertOneSignalNotification(list: NotificationList){
    // Insert the new list object
    try! realm.write {
        realm.add(list)
    }

    // Iterate through all list objects, and delete the earliest ones
    // until the number of objects is back to 50
    let sortedLists = realm.objects(NotificationList).sorted("createdAt")
    while sortedLists.count > totalMessage {
        let first = sortedLists.first
        try! realm.write {
            realm.delete(first!)
        }    
    }
}

这是我的领域对象

import RealmSwift

class NotificationList: Object {
    dynamic var title = ""
    dynamic var body = ""
    dynamic var createdAt = NSDate()
    let notifications = List<Notification>()


// Specify properties to ignore (Realm won't persist these)

//  override static func ignoredProperties() -> [String] {
//    return []
//  }

}

那么,在我插入新记录之前,有没有办法在领域保护重复记录插入.我是realm swift的新手.有什么帮助吗？

Answer 1

你NotificationList需要一把钥匙.

将主键设置为您的对象,如下所示:

class NotificationList: Object {
   dynamic var title = ""
   dynamic var body = ""
   dynamic var createdAt = NSDate()
   dynamic var id = 0
   let notifications = List<Notification>()

   override static func primaryKey() -> String? {
      return "id"
   }
}

然后使用add(_:update:)以下命令添加对象

realm.add(newNotification, update: true)

如果id存在,它将更新数据.