清除CoreData及其中的所有内容

Question

我对CoreData和使用它的这个应用程序很新.我正在开发一种功能,可以在我在应用程序中注销时清除整个核心数据.

我有2个sqllite文件(出于某种原因,他们认为这很方便)

如何清除所有数据的两个文件并将其重置为无数据状态？

在指南上,我已经尝试了很多方法.

如何以一对多关系清除/重置所有CoreData

如何从Core Data中删除所有对象

他们似乎都失败了.现在我想知道我做错了什么？也许有人可以解释我如何以正确的方式重置我的2个CoreData文件.

编辑:

//should clear the whole coredata database. mainly used for logout mechanism
-(void)resetCoreData
{
    for (NSPersistentStore *store in self.persistentStoreCoordinator.persistentStores)
    {
//    NSPersistentStore *store = self.persistentStoreCoordinator.persistentStores[0];
        NSError *error;
        NSURL *storeURL = store.URL;
        DLog(@"storeURL: %@", storeURL);
        NSPersistentStoreCoordinator *storeCoordinator = self.persistentStoreCoordinator;
        [storeCoordinator removePersistentStore:store error:&error];
        [[NSFileManager defaultManager] removeItemAtPath:storeURL.path error:&error];

        DLog(@"There are erreurs: %@", error);
//    [self addDefaultData];
    }

    _persistentStoreCoordinator = nil;
    _managedObjectContext = nil;
    _managedObjectModel = nil;
}

这似乎并没有为我清除CoreData.

EDIT2:

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

- (NSManagedObjectModel *)managedObjectModel
{
    if (__managedObjectModel != nil) {
        return __managedObjectModel;
    }

    NSURL *modelURL = [[NSBundle mainBundle] URLForResource:@"MyName" withExtension:@"momd"];
    __managedObjectModel = [[NSManagedObjectModel alloc] initWithContentsOfURL:modelURL];

    return __managedObjectModel;
}

- (NSPersistentStoreCoordinator *)persistentStoreCoordinator {

    if (__persistentStoreCoordinator != nil) {
        return __persistentStoreCoordinator;
    }

    NSString *storePath = [[self applicationDocumentsDirectory]

                           stringByAppendingPathComponent:@"MyName.sqlite"];

    NSFileManager *fileManager = [NSFileManager defaultManager];

    // If the expected store doesn't exist, copy the default store.
    if (![fileManager fileExistsAtPath:storePath]) {
        NSString *defaultStorePath = [[NSBundle mainBundle] pathForResource:@"MyName" ofType:@"momd"];
        if (defaultStorePath) {

            [fileManager copyItemAtPath:defaultStorePath toPath:storePath error:NULL];

        }

    }



    __persistentStoreCoordinator = [[NSPersistentStoreCoordinator alloc] initWithManagedObjectModel: [self managedObjectModel]];

    //Check to see what version of the current model we're in. If it's >= 2.0,
    //then and ONLY then check if migration has been performed...
    NSSet *versionIdentifiers = [[self managedObjectModel] versionIdentifiers];
    DLog(@"Which Current Version is our .xcdatamodeld file set to? %@", versionIdentifiers);

    if ([versionIdentifiers containsObject:@"2.0"])
    {
        BOOL hasMigrated = YES;
        if (hasMigrated==YES) {
            storePath = nil;
            storePath = [[self applicationDocumentsDirectory]
                         stringByAppendingPathComponent:@"MyName2.sqlite"];

        }
    }

    NSURL *storeUrl = [NSURL fileURLWithPath:storePath];
    NSError *error;
    NSDictionary *pscOptions = [NSDictionary dictionaryWithObjectsAndKeys:[NSNumber numberWithBool:YES], NSMigratePersistentStoresAutomaticallyOption,
                                [NSNumber numberWithBool:NO], NSInferMappingModelAutomaticallyOption,
                                nil];

    if (![__persistentStoreCoordinator addPersistentStoreWithType:NSSQLiteStoreType
                                                    configuration:nil
                                                              URL:storeUrl
                                                          options:pscOptions
                                                            error:&error]) {
        DLog(@"Unresolved error %@, %@", error, [error userInfo]);
        abort();
    }

    return __persistentStoreCoordinator;
}

---

编辑3:我仍在寻找一种方法来重置我的CoreData,好像我删除了整个应用程序并重新启动它.这样做的通常方法对我的情况不起作用.并且有2个sqllite文件.在应用程序的某个时刻发生了迁移的提示,但我不太确定何时以及如何进行迁移.错误日志显示没有用.

我不是在寻找最有效的方式.就这样.

帮助我,赏金是你的.

编辑4:最终结果:似乎我的遗留代码实例化了第二个ManagedObjectContext.我检索它的那一刻,并用它做了冲洗功能.两个sqlite文件都根据需要消失了.

感谢所有努力解决我的问题.

Answer 1

尝试以下方法来刷新数据库,它对我来说非常适合.

-(void) flushDatabase{
    [__managedObjectContext lock];
    NSArray *stores = [__persistentStoreCoordinator persistentStores];
    for(NSPersistentStore *store in stores) {
       [__persistentStoreCoordinator removePersistentStore:store error:nil];
       [[NSFileManager defaultManager] removeItemAtPath:store.URL.path error:nil];
    }
    [__managedObjectContext unlock];
    __managedObjectModel    = nil;
    __managedObjectContext  = nil;
    __persistentStoreCoordinator = nil;
}