保存或更新核心数据后未更新 Table - Swift

Question

我在我的项目中 CRUD 有以下 class：

class ProjectCoreDataStore: DegreesProtocol, DegreesStoreUtilityProtocol {

    // MARK: - Managed object contexts
    var mainManagedObjectContext: NSManagedObjectContext
    var privateManagedObjectContext: NSManagedObjectContext

    // MARK: - Object lifecycle

    init()
    {

        //let fileName: String = "PortalMDBApp.sqlite"
        let fileName: String = "MDB.sqlite"

        let fileManager:FileManager = FileManager.default
        let directory = fileManager.urls(for: .documentDirectory, in: .userDomainMask).first!

        let documentUrl = directory.appendingPathComponent(fileName)
        let bundleUrl = Bundle.main.resourceURL?.appendingPathComponent(fileName)

        // here check if file already exists on simulator
        if fileManager.fileExists(atPath: (documentUrl.path)) {
            //Document file exists!
            //return documentUrl.path
        }else if fileManager.fileExists(atPath: (bundleUrl?.path)!) {
            //Document file does not exist, copy from bundle!
            try! fileManager.copyItem(at:bundleUrl!, to:documentUrl)
        }

        // MARK: - After pass sqlite to device then run bellow code

        // This resource is the same name as your xcdatamodeld contained in your project.
        guard let modelURL = Bundle.main.url(forResource: "MDB", withExtension: "momd") else {
            fatalError("Error loading model from bundle")
        }

        // The managed object model for the application. It is a fatal error for the application not to be able to find and load its model.
        guard let mom = NSManagedObjectModel(contentsOf: modelURL) else {
            fatalError("Error initializing mom from: \(modelURL)")
        }

        let psc = NSPersistentStoreCoordinator(managedObjectModel: mom)
        mainManagedObjectContext = NSManagedObjectContext(concurrencyType: .mainQueueConcurrencyType)
        mainManagedObjectContext.persistentStoreCoordinator = psc

        let urls = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask)
        let docURL = urls[urls.endIndex-1]
        /* The directory the application uses to store the Core Data store file.
         This code uses a file named "DataModel.sqlite" in the application's documents directory.
         */
        let storeURL = docURL.appendingPathComponent("MDB.sqlite")
        do {
            try psc.addPersistentStore(ofType: NSSQLiteStoreType, configurationName: nil, at: storeURL, options: nil)
        } catch {
            fatalError("Error migrating store: \(error)")
        }

        privateManagedObjectContext = NSManagedObjectContext(concurrencyType: .privateQueueConcurrencyType)
        privateManagedObjectContext.parent = mainManagedObjectContext
    }

    deinit
    {
        do {
            try self.mainManagedObjectContext.save()
        } catch {
            fatalError("Error deinitializing main managed object context")
        }
    }

    // MARK: - CRUD operations - Generic enum result type

    func updateLanguageDB(idLang: String,
                          completionHandler: @escaping (() throws -> String) -> Void) {

        privateManagedObjectContext.perform {
            //MARK: Clear selectedLang
            do {
                let clears = NSFetchRequest<NSFetchRequestResult>(entityName: "ShortMajorTBL")
                let query = NSPredicate(format: "(%K = %@)",
                                        "identifier","L100")
                clears.predicate = query
                let results = try self.privateManagedObjectContext.fetch(clears)
                let resultData = results as! [ShortMajorTBL]
                for object in resultData {
                    object.isSelected = "false"
                }
                do {
                    try self.privateManagedObjectContext.save()
                }catch{
                }
                completionHandler{return "SeuccesClear"}
            } catch {
                completionHandler { throw DegreesStoreError.CannotFetch("Cannot fetch orders") }
            }

            //MARK: Update selectedLang
            do {
                let updateRequest = NSFetchRequest<NSFetchRequestResult>(entityName: "ShortMajorTBL")
                let query = NSPredicate(format: "(%K = %@) AND (%K = %@) AND (%K = %@)",
                                        "isSelected","false",
                                        "langId",idLang.uppercased(),
                                        "identifier","L100")
                updateRequest.predicate = query
                let results = try self.privateManagedObjectContext.fetch(updateRequest)
                let resultData = results as! [ShortMajorTBL]
                for object in resultData {
                    object.isSelected = "true"
                }
                do {
                    try self.privateManagedObjectContext.save()
                }catch{
                }
                completionHandler{return "SeuccesUpdate"}
            } catch {
                completionHandler { throw DegreesStoreError.CannotFetch("Cannot fetch orders") }
            }
        }
    }


    func fetchListSelectedLangShortTermDB(completionHandler: @escaping (() throws -> [ShortMajorTBL]) -> Void){
        privateManagedObjectContext.perform {
            do{
                let fetchRequest = NSFetchRequest<NSFetchRequestResult>(entityName: "ShortMajorTBL")
                let query = NSPredicate(format: "(%K = %@) AND (%K = %@)",
                                        "isSelected","true",
                                        "identifier","L100")
                fetchRequest.predicate = query
                let results = try self.privateManagedObjectContext.fetch(fetchRequest) as! [ShortMajorTBL]
                for ss in results{
                    print("1 >>> \(ss.idLang)")
                }
            }catch{
            }

        do{
            let fetchRequest = NSFetchRequest<NSFetchRequestResult>(entityName: "ShortMajorTBL")
            let query = NSPredicate(format: "(%K = %@) AND (%K = %@)",
                                    "isSelected","true",
                                    "identifier","L100")
            fetchRequest.predicate = query
            let results = try self.privateManagedObjectContext.fetch(fetchRequest) as! [ShortMajorTBL]
            for ss in results{
                print("1 >>> \(ss.idLang)")
                print("1 >>> \(ss.id)")
            }
        }catch{
        }
        }
    }
}

问题： 我正在使用这个 func updateLanguageDB 来更新记录，当我在 func updateLanguageDB 中用波纹管 query 测试时告诉我更新成功：

do{
    let fetchRequest = NSFetchRequest<NSFetchRequestResult>(entityName: "ShortMajorTBL")
    let query = NSPredicate(format: "(%K = %@) AND (%K = %@)",
                            "isSelected","true",
                            "identifier","L100")
    fetchRequest.predicate = query
    let results = try self.privateManagedObjectContext.fetch(fetchRequest) as! [ShortMajorTBL]
    for ss in results{
        print("1 >>> \(ss.id)")
    }
}catch{
}

但是当我在其他页面使用上面的 query 时没有得到任何结果？？！！

这是我的 fun:

func fetchListSelectedLangShortTermDB(completionHandler: @escaping (() throws -> [ShortMajorTBL]) -> Void){
    privateManagedObjectContext.perform {
        do{

            let fetchRequest = NSFetchRequest<NSFetchRequestResult>(entityName: "ShortMajorTBL")
            let query = NSPredicate(format: "(%K = %@) AND (%K = %@)",
                                    "isSelected","true",
                                    "identifier","L100")
            fetchRequest.predicate = query
            let results = try self.privateManagedObjectContext.fetch(fetchRequest) as! [ShortMajorTBL]
            print("1 ++++ \(results.count)")
            for ss in results{
                print("1 >>> \(ss.idLang)")
                print("1 >>> \(ss.id)")
            }
        }catch{
        }
    }
}

这是我的 xcdatamodeld 和 debug sqlite :

并且：

注意当我从设备中获取 sqlite 时，我没有看到任何更新记录。

Answer 1

我删除了 privateManagedObjectContext 并仅使用了 mainManagedObjectContext，现在干得不错。并从主要状态中删除 Z_PK。

保存或更新核心数据后未更新 Table - Swift

Not update Table after saving or updating Core data - Swift

ios

swift

core-data

nspredicate

nsfetchrequest