iOS应用程序错误地为一个测试用例创建多个sqlite文件，从而导致重复的文件下载

我已经在ios应用程序中实现了核心数据。现在，当下载文件并将其保存到数据库时，如果我在两者之间退出该过程，然后再次启动，则每次都会创建新的sqlite文件。这导致应用程序从数据库中获取前几个文件，而将后几个文件存储在一个单独的数据库中，以后不会访问该数据库。这最终会导致每次下载以后的文件并为其创建一个新的数据库。我很困惑如何解决这个问题。以下是我在AppDelegate类hoever中的核心数据代码，我还需要在后台继续运行该操作，因此无需修复：

#pragma mark - Core Data stack

@synthesize managedObjectContext = _managedObjectContext;
@synthesize managedObjectModel = _managedObjectModel;
@synthesize persistentStoreCoordinator = _persistentStoreCoordinator;

- (NSURL *)applicationDocumentsDirectory {
// The directory the application uses to store the Core Data store file. This code uses a directory named "acme.in.EcoGrid" in the application's documents directory.
return [[[NSFileManager defaultManager] URLsForDirectory:NSDocumentDirectory inDomains:NSUserDomainMask] lastObject];
}

- (NSManagedObjectModel *)managedObjectModel {
// 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.
if (_managedObjectModel != nil) {
    return _managedObjectModel;
}
NSURL *modelURL = [[NSBundle mainBundle] URLForResource:@"EcoGrid" withExtension:@"momd"];
_managedObjectModel = [[NSManagedObjectModel alloc] initWithContentsOfURL:modelURL];
return _managedObjectModel;
}

- (NSPersistentStoreCoordinator *)persistentStoreCoordinator {
// The persistent store coordinator for the application. This implementation creates and return 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:@"EcoGrid.sqlite"];
NSError *error = nil;
NSString *failureReason = @"There was an error creating or loading the application's saved data.";

NSDictionary *options = [NSDictionary dictionaryWithObjectsAndKeys:
                         [NSNumber numberWithBool:YES], NSMigratePersistentStoresAutomaticallyOption,
                         [NSNumber numberWithBool:YES], NSInferMappingModelAutomaticallyOption, nil];
if (![_persistentStoreCoordinator addPersistentStoreWithType:NSSQLiteStoreType configuration:nil URL:storeURL options:options 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] init];
[_managedObjectContext setPersistentStoreCoordinator:coordinator];
return _managedObjectContext;
}

#pragma mark - Core Data Saving support

- (void)saveContext {
NSManagedObjectContext *managedObjectContext = self.managedObjectContext;
if (managedObjectContext != nil) {
    NSError *error = nil;
    if ([managedObjectContext hasChanges] && ![managedObjectContext save:&error]) {
        // Replace this implementation 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();
    }
}
}

-(void)deleteAndRecreateStore{
NSPersistentStore * store = [[self.persistentStoreCoordinator persistentStores] lastObject];
NSError * error;
[self.persistentStoreCoordinator removePersistentStore:store error:&error];
[[NSFileManager defaultManager] removeItemAtURL:[store URL] error:&error];
_managedObjectContext = nil;
_persistentStoreCoordinator = nil;
[self managedObjectContext];
}

---

非常感谢您的帮助

在persistentStore Coordinator方法中放置一个if条件可以解决问题，如下所示：-

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

// Create the coordinator and store

NSFileManager *filemgr = [NSFileManager defaultManager];

if ([filemgr fileExistsAtPath: [[[self applicationDocumentsDirectory] URLByAppendingPathComponent:@"EcoGrid.sqlite"] absoluteString] ] == NO) {
    _persistentStoreCoordinator = [[NSPersistentStoreCoordinator alloc] initWithManagedObjectModel:[self managedObjectModel]];
    NSURL *storeURL = [[self applicationDocumentsDirectory] URLByAppendingPathComponent:@"EcoGrid.sqlite"];
    NSError *error = nil;
    NSString *failureReason = @"There was an error creating or loading the application's saved data.";

    NSDictionary *options = [NSDictionary dictionaryWithObjectsAndKeys:
                             [NSNumber numberWithBool:YES], NSMigratePersistentStoresAutomaticallyOption,
                             [NSNumber numberWithBool:YES], NSInferMappingModelAutomaticallyOption, nil];
    if (![_persistentStoreCoordinator addPersistentStoreWithType:NSSQLiteStoreType configuration:nil URL:storeURL options:options 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();
    }

}
else{

}



return _persistentStoreCoordinator;
}

---

这个单独的数据库文件的名称是什么？