当前，我正在基于id检查对象是否已存在于核心数据中，然后进行更新和插入。有什么更好的方法吗？添加了“ id”作为唯一约束，从而防止插入具有相同“ id”的对象。插入是否仅更新具有相同ID的现有对象？

   @nonobjc public class func saveUserMovies(movieJSON: [[String: Any]],user: UserProfile,isFavorites: Bool = false,isWatchlisted: Bool = false) {
        let context = MMPersistentStore.sharedInstance.privatemanagedobjectcontext
        for movie in movieJSON {
            let movieID = movie["id"] as! Int
            let fetchMovieWithIDRequest = fetchMovieRequest()
            let moviePredicate = NSPredicate(format: "id == %d",movieID)
            let sortDiscriptor = NSSortDescriptor(key: "id",ascending: false)
            fetchMovieWithIDRequest.sortDescriptors = [sortDiscriptor]
            fetchMovieWithIDRequest.predicate = moviePredicate
            
            var userMovie: UserMovie?
            context.performAndWait {
                do {
                    userMovie = try fetchMovieWithIDRequest.execute().first
                } catch {
                    print(MMErrorStrings.coreDataFetchError)
                }
                }
                if let fetchedmovie = userMovie {
                    fetchedmovie.genreIds = movie["genre_ids"] as? [Int64]
                    fetchedmovie.adult = movie["adult"] as? Bool ?? false
                    if isFavorites {
                      fetchedmovie.isFavorite = isFavorites
                    } else {
                        fetchedmovie.isWatchlisted = isWatchlisted
                    }
                    
                    fetchedmovie.video = movie["video"] as? Bool ?? false
                    fetchedmovie.backdropPath = movie["backdrop_path"] as? String
                    fetchedmovie.originalLanguage = movie["original_language"] as? String
                    fetchedmovie.originalTitle = movie["original_title"] as? String
                    fetchedmovie.overview = movie["overview"] as? String
                    fetchedmovie.posterPath = movie["poster_path"] as? String
                    fetchedmovie.releaseDate = movie["release_date"] as? String
                    fetchedmovie.releaseYear = String(fetchedmovie.releaseDate?.prefix(4) ?? "")
                    fetchedmovie.title = movie["title"] as? String
                    fetchedmovie.popularity = movie["popularity"] as? Double ?? 0.0
                    fetchedmovie.voteCount = movie["voteCount"] as? Int64 ?? 0
                    fetchedmovie.voteAverage = movie["voteAverage"] as? Double ?? 0.0
                    
                    MMPersistentStore.sharedInstance.save(context: context)
                } else {
                    let fetchedmovie = UserMovie(context: context)
                    fetchedmovie.id = movie["id"] as? Int64 ?? 0
                    fetchedmovie.user = user
                    fetchedmovie.genreIds = movie["genre_ids"] as? [Int64]
                    fetchedmovie.adult = movie["adult"] as? Bool ?? false
                    if isFavorites {
                      fetchedmovie.isFavorite = isFavorites
                    } else {
                        fetchedmovie.isWatchlisted = isWatchlisted
                    }
                    
                    fetchedmovie.video = movie["video"] as? Bool ?? false
                    fetchedmovie.backdropPath = movie["backdrop_path"] as? String
                    fetchedmovie.originalLanguage = movie["original_language"] as? String
                    fetchedmovie.originalTitle = movie["original_title"] as? String
                    fetchedmovie.overview = movie["overview"] as? String
                    fetchedmovie.posterPath = movie["poster_path"] as? String
                    fetchedmovie.releaseDate = movie["release_date"] as? String
                    fetchedmovie.releaseYear = String(fetchedmovie.releaseDate?.prefix(4) ?? "")
                    fetchedmovie.title = movie["title"] as? String
                    fetchedmovie.popularity = movie["popularity"] as? Double ?? 0.0
                    fetchedmovie.voteCount = movie["voteCount"] as? Int64 ?? 0
                    fetchedmovie.voteAverage = movie["voteAverage"] as? Double ?? 0.0
                    
                    MMPersistentStore.sharedInstance.save(context: context)
                }
            }
        }
    }