Parse.com将网络与本地数据存储同步 - 固定＆amp;解决问题

Question

我有一个Parse后端设置，我有三个类：

1. 用户
2. 地点 - 附餐厅信息
3. SavedPlace - 使用User和SavedPlace指针建模User和Place关系的对象。

我要做的是无法同步我的网络和本地数据存储区，但仅限于有变化的地方，即仅针对网络和本地不同的SavedPlace对象（使用updateAt）。但是，我遇到了固定和取消固定的问题，我到处都看，包括下面的帖子，但我似乎无法解决它。 Parse Local Datastore + Network Sync

请参阅此函数的代码，其中我只想获取更新的SavedPlace对象，取消固定本地数据存储区中的旧对象，然后重新固定到数据存储区。

问题似乎是当我重新固定从网络检索到的更新的SavedPlace对象时 - 它似乎删除了本地数据存储中的Place对象。如下图所示，SavedPlace和Place对象都固定并重新固定SavedPlace对象，删除除了我重新编写的SavedPlace对象之外的所有Place对象。

SQLite of Local Datastore

任何方式围绕这个？我正确使用pinAllInBackground吗？

感谢你的帮助。

func fetchUpdatedSavedPlacesRemotelyAndPinLocally() {

    if let user = PFUser.currentUser(),
        let lastUpdateLocalDatastore = self.userDefaults.objectForKey("lastUpdateLocalDatastore") {

        // Fetch the places from Parse where lastUpdateDate in Parse is newer than the lastUpdateLocalDatastore
        print("Current lastupdateLocalDatastore: \(lastUpdateLocalDatastore)")
        let savedPlaceQueryParse = PFQuery(className: "SavedPlace")
        savedPlaceQueryParse.whereKey("user", equalTo: user)
        savedPlaceQueryParse.includeKey("place")
        savedPlaceQueryParse.includeKey("objectId")
        savedPlaceQueryParse.whereKey("updatedAt", greaterThanOrEqualTo: lastUpdateLocalDatastore)
        savedPlaceQueryParse.findObjectsInBackgroundWithBlock {
            (updatedSavedPlacesNetwork: [PFObject]?, error: NSError?) -> Void in
            if let updatedSavedPlacesNetwork = updatedSavedPlacesNetwork {
                if updatedSavedPlacesNetwork != [] {
                    print("Success - retrieved \(updatedSavedPlacesNetwork.count) updated places from Parse")

                    // Create an array of objectIds of the updated saved places to match against in the Local datastore
                    var updatedSavedPlaceObjectId = [String]()
                    for updatedSavedPlaceNetwork in updatedSavedPlacesNetwork {
                        updatedSavedPlaceObjectId.append(updatedSavedPlaceNetwork.objectId!)
                    }

                    // Fetch these updated saved places from the Local Datastore
                    let savedPlaceQuery = PFQuery(className: "SavedPlace")
                    savedPlaceQuery.fromLocalDatastore()
                    savedPlaceQuery.whereKey("user", equalTo: user)
                    savedPlaceQuery.includeKey("place")
                    savedPlaceQuery.includeKey("objectId")
                    savedPlaceQuery.whereKey("objectId", containedIn: updatedSavedPlaceObjectId)
                    savedPlaceQuery.findObjectsInBackgroundWithBlock {
                        (updatedSavedPlacesLocal: [PFObject]?, error: NSError?) -> Void in
                        if error == nil {
                            if let updatedSavedPlacesLocal = updatedSavedPlacesLocal {

                                // Unpin the updated saved places from the Local Datastore
                                PFObject.unpinAllInBackground(updatedSavedPlacesLocal) { (success: Bool, error: NSError?) -> Void in
                                    if (success) {
                                        print("Success - \(updatedSavedPlacesLocal.count) updated saved places unpinned from Local Datastore")

                                        // Pin the updated saved places from Parse to the Local Datastore and update the lastUpdateLocalDatastore
                                        PFObject.pinAllInBackground(updatedSavedPlacesNetwork) { (success: Bool, error: NSError?) -> Void in
                                            if (success) {
                                                print("Success - \(updatedSavedPlacesNetwork.count) updated saved places pinned to Local Datastore")
                                                self.userDefaults.setObject(NSDate(), forKey: "lastUpdateLocalDatastore")
                                                print("New lastUpdateLocalDatastore: \(self.userDefaults.objectForKey("lastUpdateLocalDatastore"))")
                                            }
                                            else {
                                                print("Fail - updated saved places not pinned and returned with error: \(error!.description)")
                                            }
                                        }
                                    }
                                    else {
                                        print("Fail - updated saved places not unpinned and returned with error: \(error!.description)")
                                    }
                                }
                            }
                        }
                        else {
                            print("Fail - updated saved places not fetched in Local Database and returned with error: \(error!.description)")
                        }
                    }
                }
                else {
                    print("No updates")
                }
            }
            else {
                print("Fail - load from Parse failed with error: \(error!.description)")
            }
        }
    }
}