提取时的核心数据错误

Question

我是Core Data的新手，我一直在试图获取我创建的实体，但我不断收到抛出的错误消息。

的错误是如下：当我的视图控制器上viewDidAppear被称为被抛出

CoreData: error: -addPersistentStoreWithType:SQLite configuration:(null) URL:file:///var/mobile/Containers/Data/Application/4A0BBC17-674F-4A5D-80F7-72174D71B95F/Documents/Todogorithm.sqlite options:(null) ... returned error Error Domain=NSCocoaErrorDomain Code=134100 "The managed object model version used to open the persistent store is incompatible with the one that was used to create the persistent store." UserInfo={metadata={ 
    NSPersistenceFrameworkVersion = 641; 
    NSStoreModelVersionHashes =  { 
     Task = <3db44fe3 d21215ef eee9476a ae204647 b49829de 00b4784c 7715b5ff a252dcab>; 
    }; 
    NSStoreModelVersionHashesVersion = 3; 
    NSStoreModelVersionIdentifiers =  (
     "" 
    ); 
    NSStoreType = SQLite; 
    NSStoreUUID = "DFB8723E-7D5B-44A0-AFB9-E9E0F7E39E85"; 
    "_NSAutoVacuumLevel" = 2; 
}, reason=The model used to open the store is incompatible with the one used to create the store} with userInfo dictionary { 
    metadata =  { 
     NSPersistenceFrameworkVersion = 641; 
     NSStoreModelVersionHashes =   { 
      Task = <3db44fe3 d21215ef eee9476a ae204647 b49829de 00b4784c 7715b5ff a252dcab>; 
     }; 
     NSStoreModelVersionHashesVersion = 3; 
     NSStoreModelVersionIdentifiers =   (
      "" 
     ); 
     NSStoreType = SQLite; 
     NSStoreUUID = "DFB8723E-7D5B-44A0-AFB9-E9E0F7E39E85"; 
     "_NSAutoVacuumLevel" = 2; 
    }; 
    reason = "The model used to open the store is incompatible with the one used to create the store"; 
} 

错误。这里是我的viewDidAppear： [super viewDidAppear：animated];

AppDelegate *appDelegate = [[AppDelegate alloc] init]; 

NSManagedObjectContext *context = [appDelegate managedObjectContext]; 

NSFetchRequest *request = [[NSFetchRequest alloc] initWithEntityName:@"Task"]; 
_results = [context executeFetchRequest:request error:nil]; 

的代码中有调用我的appDelegate的managedObjectContext，并且该方法中的persistentStoreCoordinator方法被调用（这是错误实际上是抛出）。从AppDelegate.m这两种方法是如下：

- (NSPersistentStoreCoordinator *)persistentStoreCoordinator { 
    // The persistent store coordinator for the application. This implementation creates and returns a coordinator, having added the store for the application to it. 
    if (_persistentStoreCoordinator != nil) { 
     return _persistentStoreCoordinator; 
    } 

    // Create the coordinator and store 

    _persistentStoreCoordinator = [[NSPersistentStoreCoordinator alloc] initWithManagedObjectModel:[self managedObjectModel]]; 
    NSURL *storeURL = [[self applicationDocumentsDirectory] URLByAppendingPathComponent:@"Todogorithm.sqlite"]; 
    NSError *error = nil; 
    NSString *failureReason = @"There was an error creating or loading the application's saved data."; 
    if (![_persistentStoreCoordinator addPersistentStoreWithType:NSSQLiteStoreType configuration:nil URL:storeURL options:nil error:&error]) { 
     // Report any error we got. 
     NSMutableDictionary *dict = [NSMutableDictionary dictionary]; 
     dict[NSLocalizedDescriptionKey] = @"Failed to initialize the application's saved data"; 
     dict[NSLocalizedFailureReasonErrorKey] = failureReason; 
     dict[NSUnderlyingErrorKey] = error; 
     error = [NSError errorWithDomain:@"YOUR_ERROR_DOMAIN" code:9999 userInfo:dict]; 
     // Replace this with code to handle the error appropriately. 
     // abort() causes the application to generate a crash log and terminate. You should not use this function in a shipping application, although it may be useful during development. 
     NSLog(@"Unresolved error %@, %@", error, [error userInfo]); 
     abort(); 
    } 

    return _persistentStoreCoordinator; 
} 


- (NSManagedObjectContext *)managedObjectContext { 
    // Returns the managed object context for the application (which is already bound to the persistent store coordinator for the application.) 
    if (_managedObjectContext != nil) { 
     return _managedObjectContext; 
    } 

    NSPersistentStoreCoordinator *coordinator = [self persistentStoreCoordinator]; 
    if (!coordinator) { 
     return nil; 
    } 
    _managedObjectContext = [[NSManagedObjectContext alloc] initWithConcurrencyType:NSMainQueueConcurrencyType]; 
    [_managedObjectContext setPersistentStoreCoordinator:coordinator]; 

任何想法，为什么persistentStoreCoordinator错误被称为？

Answer 1

您可能已在Xcode中更改了您的托管对象模型，但您仍然在装有旧数据模型配置的设备/模拟器上安装了应用程序。

这就是为什么你得到这个错误。 如果您的应用程序是全新的，而且您不必担心与已安装应用程序的兼容性，则可以从设备/模拟器中删除旧应用程序并安装新应用程序。

如果您需要保持旧版数据模型配置与新版数据模型配置的兼容性，则应该使用版本控制模型并在新版数据模型版本中进行所有更改。

Answer 2

从模拟器/设备中删除应用程序，执行清理并重新构建您的项目。

每当您对Core Data定义执行更改时，删除安装在物理设备或模拟器上的应用程序，再次清理项目并重新构建。